MSU LIBRARIES -—._. RETURNING MATERIALS: Place in book dr65_to remove this checkout from your record. FINES will be charged if book is returned after the date stamped below. fl INTRAI‘DLECUIAREFFECI‘SOFMEMCGJRDINATION (N'IHEPl-WSTRYOFIGEYIUNES Rosarazy Bartoszek A DISSERIATICN Ehtnflxxed.to Michigan State University in partial fulfilhmt of the requirarents f6]: the degree of MR OF PHILOSOPHY Department of Chenistry 1981 ABSTRACT IN'I‘RANDIECULAR EFFECTS OF MAL C(XJRDINATION ON THE PWSTW OF KEI'ONE‘S By Rosemary Bartoszek The photoprocesses of pyridyl ketones coordinated to rhenium(I) and mtheniurMII) natal canplexes were investigated. The triplet photoreduction reaction of the pyridyl ketone was used to monitor the reaction from the upper excited state. Irradiation into the ketone chratophore did not always lead to photoreduction from the ligand excited state. In addition to decay from the ground state, additional decay pathways to lower lying natal-natal (LF) and natal to ligand charge transfer (MLCI') excited states are also present. When pyridyl ketone photoreduction was observed , it was possible to detennixa the rate of this internal conversion. Type II fragnantation was not observed for the bmn'otricarbonyl- rheniuMI) pyridyl ketone canplexes. There is a decreased ability for light absorption by the pyridyl ketone carbonyl chrarophore . This is evidenced by intense natal derived transitions overlapping the pyridyl ketone n,1r* transition in the absorption Spectra. Canplex deccnposition occurs before a naasurable amount of product formation. Type II fragnantation was observed for the pyridyl ketone pentaamnixarutheniunllll canplexes. A decreased ability to absorb c an" _.‘_4 --..n—~ . a '“ql‘. .- ...h v “.Q- a". .— hfinvn. light directly into the carbonyl chrarophore lowers the Type II fragnantation efficiency. The 4’11 for the pyridyl ketone hydro— chloride salts are comparable to the (DII for the rutheniurMII) oanplexes when corrections for light absorption are made. This suggests that with coordination of the lone electron pair of the pyridyl nitrogen, the sana effects Operate on the l,4-biradical. Ligand photosubstitution occurs only with the nata pyridyl ketone pentaanminerutl‘aniuMII) canplexes from the LF excited state. Side reactions, anong them complex decomposition, ccmpete with the inter- nolecular photoreduction and the rate of decay fran the upper excited state cannot be quantitatively determined. The lifetina data for the canplexes and corresponding hydrochloride salts were used to 8 l detentfine a rate of less than 10 sec- for internal conversion to the lower energy excited states . To my parents, Aloisius and Frances Bartoszek and my husband, Ranan. ii 'n'a author wishes to thank Dr. Peter J. Wagner for his untiring support and generous help which were instrurantal in helping to nold this dissertation. His sense of hmor and words-.of wisdcm made my stay at Michigan State a very rewarding experience. I acknowledge my undergraduate professors at 8mm, R. D. Beranan, A. Padwa, W. Dannhauser and O. T. Beachley. Their encourage- ment and enthmiasm for chemistry encouraged me to persue this graduate degree in claustry. The encouragement and support of my family and friends, especial- ly m Ioza, Bob Tieckelmann, Kathyl Lutanski and Joe Bartoszek, willalwaysberanatbered. Ialsowishtothankthemanbersofthe Chanistry Departnant, past and present, for their many stimulating discussions and close friendships. Finally, I wish to thank the National Science Foundation for their support through research assistantships , and fellowship support fmanCIunicalCatpanyanitlaGraduate-Scrool. iii TABLE OF CONTENTS Page LIST OF TABLES . . . .............................................. x LIST OF FIGURES ................................................ XVIII INTRODIIZTION Electronic Transitions in Organonatallic Complexes ........ 1 Organoratallic Photochemistry ............................. 2 Photochemistry of the Ruthenium(II) Complexes ............. 4 Photochemistry of the Rhenium(I) Complexes ................ 10 Photochemistry of the Aromatic Alkyl Ketones .............. 12 The Norrish Type II Reaction ......................... l4 Intermolecular Photoreduction ........................ 16 Photochemistry of the Pyridyl Alkyl Ketones .......... 20 Kinetics ............................................. 21 Research Goals ............................................ 23 RESULTS Pyridyl Ketones and Hydrochloride Salts ................... 26 Compound Preparation ................................. 26 Intranolecular Photoreduction ........................ 26 Photoproduct Identification ..................... 26 Quantum Yields ........... . ...................... 27 Quenching Studies. . . . ........................... 39 Intersystom Crossing Studies ......................... 39 Intermolecular Photoreduction ........................ 4 3 Pmtoproduct Identification ..................... 43 1V ‘.‘~- - .\ U“ K IV Page Quantum Yields .................................. 43 Quenching Studies ............................... 44 Spectrosc0pic Studies ................................ 4 9 Ruthenium Complexes ....................................... 5 3 Preparation and Identification ....................... 53 Complex Stability .................................... 6 l Intranolecular Photoreduction ........................ 66 PhotOproduct Identification ..................... 66 Quantum Yields and Quenching Studies ............ 67 Intermolecular Photoreduction ........................ 67 Emission Studies ..................................... 7 3 Rhenium Complexes . . ....................................... 73 Preparation and Identification ....................... 7 3 Complex Stability .................................... 77 Photoproduct Identification and Quantum Yield Studies 7 9 Intersystem Crossing Studies ......................... 80 Emission Spectra ..................................... 80 DISCUSSION Pyridyl Ketme Photochemistry ............................. 86 Quantum Yields. . . . .1 ....... . .......................... 86 Quenching Studies ............. ................ 88 Reactivity and Efficiency........... ................. 94 Synthesis and Properties of the Organonetallic Complexes. . 97 Pyridyl Ketone Pentaamnu’nerutheniuMII) Complexes . . . . 97 Pyridyl Ketone Brototricarbonylrhenium (I) Complexes . . 100 Photochemistry of the Organotatallic Complexes ............ 101 v Page Pyridyl Ketone PentaanminerutheniuMII) Complexes. . . . 101 Pyridyl Ketone Brorotricarbonylrhenium(I) Complexes. . 113 SW ........................................................ 119 Suggestions for Further Study ............................. 121 EXPERIMENTAL Instrurantation ................................ '. .......... 123 Chemicals ..... ' ............................................ 124 Solvents ............................................. 124 Benzene ......................................... 124 Acetonitrile ................. . .................. 124 Pyridine ........................................ 124 tit-Butyl Alcohol .............................. 125 2-Methyltetrahydrofuran ......................... 125 2-mthylbutane ............. . . . . . ................ 125 Ethanol ......................................... 125 Ethyl ether ..................................... 125 Methylcyclohexane ............................... 125 Water ........................................... 126 Hydrogen Donors ...................................... 126 Toluene ......................................... 126 p—Xylene. . . . . . .................................. 126 2-Propanol ...... . ............ . .................. 126 l-Phenylethanol ................................. 126 Internal Standards ................................... 126 Cyclohexane ..................................... 126 Hexadecane ............................... . ....... 126 Heptadecane. ..... . ........ . . . . .................. 126 Octadecane. . ............. . ...................... 127 Nonadecane ............. . . ....................... 127 Eicosane ......... . ....... . ......... . ............ 127 Heneioosane.. ...... . ..... ....... . ...... 127 Quencl'ars ...... . ............. . ....................... 127 2 ,S-Dimathyl-Z, 4-hexadiene. . . . . . . . .............. 127 c___is- and tran___s-l, 3-Pentadiene ..... . ........ ' ..... 127 c_is-l 3,-Pentadiene.............. ................ 127 _trans-Stilbene ............. . . ....... . ........... 127 Ethyl Sorbate .......... . .......... . ............. 127 vi Page Naphthalene ..................................... 127 Phenylalkyl Ketones .................................. 128 AcetOphenone .................................... 128 BenZOphenone .................................... 128 Valer0phenone ................................... 128 Pyridylalkyl Ketones ................................. 128 ZeAcetylpyridine... ............................. 128 3—Acetylpyridine ................................ 128 4tAcetylpyridine ................................ 129 l—(2-Pyridyl)butanone ........................... 130 1—(3-Pyridy1)butanone ........................... 131 1-(4-Pyridy1)butanone ........................... 132 l—(Z-Pyridy1)pentanone .......................... 132 l-(3-Pyridy1)pentanone ........................... 133 l-(4-Pyridyl)pentanone .......................... 133 42Methyl-l-(2-pyridy1)pentanone ................. 134 39Methy1-l-(3-pyridy1)butanone .................. 134 3_K for 3-nathyl-l- (3-pyridyl)butanone .......... 188 64 . Stern Volmar data for 3-mathy1-1- (4-pyridy1)butanone ..... 189 65 . Data for the effect of concentration of tert—butyl alcohol m «>11 for 3-nathyl-l-(4—pyridy1)butanone ........ 189 66. Data for ¢-K for 3-nathyl-l- (4-pyridyl)butanone .......... 190 67. Stern Volnar data for 4-mathyl-l-(4-pyridy1)pentanone. . . . 190 68. Data for the effect of concentration of tert-butyl alcohol on 4511 for 4-methy1-1— (4-pyridy1)pentanone ....... 191 69. Data for the effect of concentration of 4-mathy1-l- (4-pyridyl)paltanone on 4’11 ........ . . . . . . . ............... 191 70. Data for °—K for 4-nathy1-1- (4-pyridy1)pentanone ......... 192 71. Stem Volmar data for l- (2-pyridyl)butanone hydrochloride 192 72. Data for the effect of concentration of tert-butyl alcohol on «II for l- (2-pyridyl)butanone hydrochloride. . . 193 73. Data for the effect of concentratioi of l—(2-pyridy1) butarme hydrochloride on (”II ............................ 193 74 . Data for Q-K for 1— (2-pyridyl) butanone hydrochloride ..... 193 75. Data for 41K for l-(3-pyridyl)butancne hydrochloride ..... 194 76. Data for ¢-K for 1-(4-pyridy1)buta.rone hydrochloride ..... 194 Table Page 77. Data for the effect of concentration of 1-(3-pyridyl) butanone hydrochloride on 4511 ........................... 78. Stem Volmer data for l-(4-pyridy1)butanone hydrochloride 195 195 79. Data for the effect of concentration of tert-butyl . alcohol on 4’11 for l-(3-pyridy1)butanone hydrochloride. . . 196 80. Stern Volnar data for 1-(3-pyridy1)butanone hydrpchloride 196 81. Data for the effect of concentration of 1-(4-pyridy1) butanone hydrochloride on 4’11 ............................ 82 . Data for the effect of concentration of tert-butyl alcohol m 4511 for 1- (4'-pyridy1)butanole hydrochloride. . . 197 197 83. Stern Volnar data for 1-(2-pyridy1)pentanone hydro— chloride. . . ........................ . ..................... 198 84 . Data for the effect of concentration of tert-butyl alcohol on 4’11 for l-(2-pyridy1)pentanone hydrochloride. . 198 85. Data for the effect of concentration of l- (2-pyridy1) pentanone hydrochloride on 4’11" ..... . ..... .. ..... . ...... 198 86. Data for _K for l-(2-pyridy1)pentanone hydrochloride. . . . 199 87. Stem Volnar data for l-(3-pyridyl)pentanone hydrochlo- ride. . . . ....... . ............ . ............................ 199 88. Data for the effect of concentration of l-(3-pyridyl) pentanoie hydrochloride on 4n. .......................... 200 89. Data for the effect of concentration of tert—butyl alcohol on 411 for 1-(3-pyridyl)pentanone hydrochloride. . 200 90. Data for _K for 1- (3—pyridy1)pentanone hydrochloride. . . . 200 91. Stern Volmer data for 1-(4-pyridy1)pentanone hydrochlo- rmOOOOOOOOOOOOOOOOOOOOOOOO...OOOOOOOOOOOOOO. ........... 201 92. Data for the effect of concentration of tert—butyl alcohol on (p11 for 1- (4-pyridy1)pentano1e hydrochloride. . 202 93 . Data for the effect of concentratioi of l- (4-pyridy1) pentanone hydrochlorideonmn........ ..... ....... 202 94. Data for ¢~K for 1-(4-pyridyl)penta1one hydrochloride. . . . 202 95 . Stern Volmer data for 4-mathy1-1— (2-pyridyl) pentanone hydrochloride. ................... . ............. . ......... 203 )Q'v 239 I» to. O... 'M 0". c.‘ obj. ‘Aa OU: ‘na Q'Jc . 5,- my). I V! b? urfl I. Table 96 . 97. 98. 99. 100. 101 . 102 . 103. 104 . 105 . 106 O 107 . 108 . 109. 110 . 111. Data for the effect of concentration of 4-nathyl-1- (2—pyridy1)pentanone hydrochloride o1 ¢II ................ Data for 0 for 4-nathy1-1- (2-pyridyl)pentanone hydrochloride ............................................ Data for the effect of concentration of tert-butyl alcohol o1 I for 4-nathy1-l-(2-pyridy1)pentanone hydrochloride. . . . . . . ..................................... Stern Volnar data for 3-nathy1-1- (3—pyridyl)butanone hydrochloride ..... . . . . ................................... Data for d>_ for 3-nathyl-l- (3-pyridy1)butanone hydrochloride ............ . ............................... Data for the effect of cmcentration of 3-nathy1-l- (3-pyridy1) butanone hydrochloride on ¢II ........ . ........ Data for the effect of concentration of tert-butyl alcohol on «>11 for 3-nathyl-1- (3-pyridyl)butanone hydrochloride. . ........ . . . . . ............................. Data for the effect of concentration of 4-methyl-1- (4-pyridy1) pentanone hydrochloride on II ...... . . . ....... Stern Volnar data for 3-nathy1—1- (4—pyridy1)butanone hydrochloride. . . .................... . .......... . ......... Data for 4>_ for 3-nathyl-l- (4-pyridyl)butanone hydrochlor' ................................ Data for the effect of concentration of tert-butyl alcohol on 4 I for 3-nathy1-1- (4-pyridy1)butanone hydrochloridgwmw .............................. Data for the effect of concentration of 3-mathy1-1- (4-pyridyl)butanone hydrochloride on $11 . . . . . . ........... Data for for 4-nathyl-1—(4—pyridy1)pentanone hydrochlorideI ..... ........ Data for the effect of additives on 4’11 for 1— (4-pyridyl) pentanone.......... ............. . ......... . ....... . ...... XV Page 203 204 204 204 205 205 206 206 206 207 207 207 208 208 209 Table Page 112. Data for the output of the optical bench ................. 209 113 . Quantum yield data for 4-acetylpyridine hydrochloride and p—xylene in acetonitrile ............................. 210 114 . Quantum yield data for 4-acetylpyridine hydrochloride and l-phenylethanol in acetonitrile ...................... 210 115 . Quantum yield data for 3-acetylpyridine hydrochloride and l-phenylethanol in acetonitrile .......................... 210 116 . Data for the isolarization of gi_s-1 , 3-pentadiene by the pyridyl ketones .......................................... 211 117. Data for the effect of water on ¢II for l-(4-pyridy1) pentanone ................................................ 211 118 . Quantum yield data for 4-acety1pyridne hydrochloride and 2-propano1 in acetonitrile ............................... 212 119 . Quantum yield data for 3—acety1pyridine hydrochloride and 2-propanol in acetonitrile ............................... 212 120 . Data for the effect of coicentration of 4-acety1pyridine Whloride on $17118 in acetonitrile .................... 213 121 . Stern Volnar data for 4-acetylpyridine hydrochloride in acetonitrile ............................................. 213 122 . Stern Volnar data for 3-acetylpyridine hydrochloride in axetonitrile ..................... . ....................... 214 123 . Fragmantation data for the pyridyl ketone ruthenium (II) complexes....... ......................................... 214 124. Stern Volnar data for [Ru(1\lI-I3)5.(l-(4—pyridy1)pentanone)] [BF4] 2 00000000000000 o o o o o oooooooooooooooooooooooooooooooo 215 125. Stern Volnar data for [Rum-I3)5(1-(3—pyridy1)pentanone)] [w4lzoooooco 00000000000 o oooooooooooooooooooooooooooooooo 215 126. Stern Volnar data for [m1(NI-I3)5(4-nathy1)-1— (4-pyridy1) pentanone)][BF4]2........ ....... . ........................ 216 127. Stern Volnar data for [Ru(M-I3)5(3-nathy1-1-(3-pyridyl) pentarme)][BF4]2.......... .............................. 216 128. Stern Volnar data for [Ru (NH3) 5 (3-nathy1—l- (4-pyridy1) pentamna)][BF4]2.. ...... .......... ....... 217 - ‘— xvi Table 129. 130 . 131. 132 . 133 . 134 . 135 . 136 . 137 . 138 . 139. 140. 141. 142. 143 O 144 . 145 . 146 O Page Quantum yield data for [Ru(NH )5 (4-acetylpyridine)] [81“4]2 with 2-propanol in ace itrile ................... 217 Quantum yield data for [Ru(NH ) 5(3 -acety1pyridine)] [BF4]2 with 2-pr0panol in ace nitrile ................... 217 Stern Volnar data for [Ru(NH3)5(4—acetylpyridine)] [BF2]2. 218 Stern Volnar data for [Ru (NH3) 5(3-acetylpyridine)] [BF4]2. 218 Fragmentation data for the rhenium (I) pyridyl ketone complexes ................................................ 219 Qunatum yield data for the ruthenium (II) acetylpyridine complexes ................................................ 220 Photochemical data for BrRe(OO)3(2VP)2 ................... 220 Photochemical data for BrRe(CO)3(3VP)2 .................... 220 Photochemical data for BrRe(CO)3(4VP)2 and BrRe(CO)3(4AP)2 221 Data for the isomerization of fi-l ,3—pentadiene sensitiz- zed by BrRe(OO) 3(pyridine)2 .............................. 221 Data for the sensitized isonarization of trans-stilbene by BrRe(OO) 3 (pyridine) 2. . . ............................... 222 Data for the sensitized isonarization of c_i_s_-l ,3—penta- diene by BrReKJO)3[l--(3-pyridy1)pentanone]2 .............. 222 Data for the sonsitized isonarization of c_is—l ,3—penta- diene by BrRe(CO)3[1-(2-pvyridyl)pentanone]2 .............. 222 Data for the sensitized isonarization of trans—stilbene by BrRe(C10)3[1-(3-pyridy1)pentanone]2 .................... 223 Data for the sensitized isomerization of gig—1 , 3—penta- diene by BrRe(CO)3[1-(4-pyridy1)pentanone]2 .............. 223 Data for the sensitized isonarization of trans—stilbene ; I. by 81‘Re ((1)) 3[1- (ll—pyridyl)pel'ntansonn'ne]2 .................... 224 Data for the sernsitized isonarization of gi_s-1 ,3-penta- diene by BrRe(CI)) 3 (3-benzoylpyridine)2 ................... 224 Data for the sensitized isonarization of trans-stilbene by BrRe(CO)3(3-benzoylpyridine)2 ........... . ..... . ....... 224 __ xvii LIST OF FIGURES Figure 1. 12. 13. Simplified molecular orbital diagram of a penta- ammineruthenium(II) pyridyl ketone complex ............... Jablonski diagram for a phenyl alkyl ketone .............. The mechanism of the Norrish Type II reaction ............ The nachanism for the reaction of trifluoroacetophenone with toluene in benzene .................................. Effect of concentration of tert-butyl alcohol on quantum yield of acetylpyridine foma'“ ticn for ZVP (O) , 3VP (A) . 4 VPCI), zvpnrzlm), 3VPHc1(A) and Warm.) ............ Effect of concentration of tert—butyl alcohol on quantum yield of 4-acety1pyridine formation for 4BP (.) , BMe43P (O). 4VP(D) and yMe4vp(A) ............................. Effect of corncentration of ketone on quantum yield for 2VP(A), 3VP(.) and 4WD) in acetonitrile; 4VP(O) in benzene and 4VPK:1(.) in acetonitrile ........... . . . . . Effect of concentration of ketone on quantum yield for A 43H ), 4VP(L__]) and yMe4VP(A) in acetonitrile; 439(0), 4VP( )anayMe4VPm) in ....... . ......... Stern Volnar plot for BMe3BP in benzene (O); BMe3BP(.:) , 3BP(A) and mm) in acetonitrile ................... Stern Volnar plots for 3VPIC1(O) , 4VPI£1(.) . BMe3BPII21 (A) and yMe4VPI-C1(A) in acetonitrile..... .............. The sensitized isonarization of fi-l , 3-pentadiene by 4VP (O) and 3VP(A) in benzene....... ....................... Dependence of quantum yield on 1 ,2-di-p—tolylethane on p—xylene concentration, 4-acetylpyridine hydrochloride in acetonitrile ............ . ............................. of quantum yield of acetophenone formation on 1—phenylethanol concentration in acetonitrile , 4-acety1— pyridine hydrochloride (0) and 3-acetylpyridine hydro— chloride(.)....... ............ . ................... . ..... xviii Page 13 14 19 34 35 36 37 40 41 42 45 46 Figure 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. Dependence of quantum yield of acetone formation on 2—pr0pano1 concentration in acetonitrile , 4-acety1— pyridine hydrochloride and 3-acety1pyridine hydro— chloride ................................................. Stern Volnar plots for 4APHC1 in the presence of 0.4 M 2-propanol(O) and 3APHCl in the presence of 0.66 M 2-propano1(.) in acetonitrile solution .................. Phosphorescence spectra of 1- (4-pyridy1)pentanone in 5 : l nathylcyclohexane : 2-mathy1butane (---) and ethanol (---) ; l. (4-pyridy1)pentanone hydrochloride in ethanol ( ------ ); 77K ............................................... Phosphorescence spectra of 1- (3-pyridyl) pentanone in 5 : 1 nathylcyclohexane : 2—mathy1butane (-——-) and ethanol (---); 1- (3-pyridy1)pentanone hydrochloride in ethanol (m m); 77K ............................................... Phosphorescence spectrum of 1- (2-pyridy1) pentanone ....... Absorption spectra of 5.4 x 10’4 M [Ru(NH3)5(l-(4-pyri— dy1)pe:rntanorne)][813'4]2 (—) , 5.4 x 10“1 M 1-(4-pyridyl)- pentanone (—--) and 5.1 x 10’4 M l-(4-pyridy1)pentanone hydrochloride (-- .. -) in acetonitrile ...................... Absorption spectra of 1.3 x 10-4 M [Ru(Mi3)5(l—(3-pyri- dyl)pentancne)] [131?412 (—-) , 1.3 x 10'4 M 1-(3-pyridy1)- pentanone (---) and 1.3 x 10‘4 M l-(3-pyridy1)pentanone hydrochloride (- . - --) in acetonitrile ...................... Absorption spectra of 1 x 10'5 M [Ru(NH3)5(1-(2-pyridy1)- pentanone” [BF4]2 (——) and l x 10'.5 M 1-(2-pyridyl)pen— tancne (~-- ~) in acetonitrile ............................. Absorption spectra of [Ru(1\lI'13)5(plyridine)][BF4]2 in aqueous solution at 1.3 x 10-4 M (—--) and acetonitrile at 1.1 x 10"4 M (---). .................................. Irnfrared spectrum of [Ru(NI‘13)5(plyridine)1[BF4]2 .......... Infrared spectrum of [Ru(l\1H3)5(l-(4-pyridy1)pentanone)] [BF4 2 ................................................... xix Page 47 48 50 51 52 57 58 59 6O 62 62 A. a"! «A I .U. 1! fr. )1 as. :1 6‘. ‘1 h .-" Figure 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. Solution stability upon exposure to light of Ru Me4VP in A) aqueous solution. B) acetonitrile solution ......... Stem Volnar plots for RuyMe4vp( ), Ru4VP(.) , Ru3VP (D) , RuBMeBBP(-) and Ru8Me4BP ) in acetonitrile ...... Dependence of quantum yield of acetone formation on 2-pr0panol concentration in acetonitrile, Ru4AP (O) and RuBAP (.) ........................................... Absorption spectra of 7.7 x lo-SM BrRe(CO)3[1-(3-pyridy1) pentanone] (-—) and 2.52 x 10'4 M 1-(3-pyridyl)pentanone (---) in benzene ......................................... Absorption spectra of 1.01 x 10'4 M BrRe(CO)3[1-(4-pyri- dy1)pentanone] (——) and 2.52 x 10‘4 M 1—(3-pyridy1)pen- tanone (---) in benzene .................................. The sensitized isonarization of gi_s_-l ,3-pentadiene by Re3VP(O), Re4VP(.) and Re(3-benzoy1)pyridine (U) in benzene ............ . ..................................... The emission spectra of Re3VP in 5:1 mathylcyclohexane: 2-mathy1butane (-—-); nathyltetrahydrofuran (---) and EPA (mm) at 77K ............................................. The emission spectra of Re4VP in 5:1 mathylcyclohexane: Z-mathylbutane (-—) and EPA (-~----) at 77 K ............... Jablonski diagram for a pyridyl ketone organonatallic complex. ......... . . . . .............. . ............. . ....... Conparison of the emission spectra of Re3VP and 3VP in 5 :1 mathylcyclohexane: Z—mathylbutane (--'); mathyl- tetrahydrofurane-qw) and EPA(‘ ------ ) at 77 K ................ Page 65 69 72 75 76 79 84 85 111 116 l n.- n . ( Q l | Q n A. ‘ \ A... o “'F‘v .o.‘ ‘ t '4 :‘.u~ .‘ I p. 5‘ e. '1. INTRODLL‘I‘ION Electronic Transitions in Org. rnoretallic Complexes The origin of excited state behavior exhibited by a transition natal complex containing organic ligands lies in the interaction of the three types of electronic transitions illustrated1 in Figure l. The highest energy transitions are the internal ligand (IL) or intra—ligand (LL) transitions involving only ligand orbitals and in general are almost unaffected by natal coordination. As a result, the emission and other excited state behavior are often very similar to that of the uncoordinated ligand.1 The lowest energy ligand field (LP) or d—d tran- sitions are derived from the natal d orbitals and are mainly localized on the central natal. These energy levels are relatively insensitive 2 ' 3 Intermediate in to solvent polarity and ligand substituents . energy are the matal-to—ligand or ligand-to—natal charge transfer (MEET or (DCI‘) transitions whose occurrence depends upon relative energies of filled orbitals. MICT transitions can be expected only when the ligands possess low—lying empty orbitals and the natal ion has filled orbitals lying higher than the higlnest filled ligand orbitals. The best ecamples are complexes containing CO, CN or aromatic amines as ligands.4 In contrast to the LF transitions, these transitions are extrenaly sensitive to solvent polarity and the nature of the organic ligand. The transition natal and the nature of the ligands together determine the relative energies of these three transitions . * * m m * * m m e —— e e g _ g g * * 1 m m * * +__d—d m m Lem ++ H t M M t M M H t g 29 EM H 29 29 d I L-L n ‘H n +4 Hr m i) ‘H m ++ H m M Mr m Mr A B C D Figure 1 . Simplified molecular orbital diagram of a pentaanmineruthe- nium(II) pyridyl ketone complex: A. Pyridyl ketone orbitals. B. Orbi- tals resulting from the mixing of natal and antibornding ligand orbitals C. Metal orbitals in the presence of an octahedral field. D. Crystal field approximation of ruthenium(II) 4d orbitals. Organoratallic Photochemistry Prior to 1955, organonatallic photochemical studies consisted mainly of investigations of isolated cases and little attempt was made to explain the quantitative observations in terms of specific excited 5 state behavior. In 1968, Crosby6 carried out fundamental . v8.“ " 7', .3 “in. .415" a "’3' "" .u‘v“ v a «1‘ n '0‘ .9-“ . --- -v“ .LJéo‘ n .D.. O a u 5.. a- O . ~" 4"- .b). w ’ y. o . t, 2'}! as -‘4 M ' aw]... in" w.- Q'Onr-a *‘ N ~I~~o ‘ . -: . ‘5. ‘- \ _.. L"II ”-51.... Q a. ... ' 7' .‘»Ve 3": - «L y. '9“ . ‘V H. . K s k " ‘V W; h . . N I ‘1 . "a ‘- v‘ ". “.5 _ 3+ 2+ spectroscOpic studies on Ru2+, Co , Os , Ir3+, Rh3 + and Pt4+ couple-(es having m-conj ugated ligands . Many of these d6 metal ion complexes were found to be highly luminescent, photochemically stable materials with potential applications in electrooptical and laser devices . Knowledge and understanding of organometallic complexes at that time was limited and summarized in reviews by Erndicott,7 Adamson et. al.,8 Fleischauer et. al. ,9 and the comprehensive book by Balzani and Cassini.10 Today the field of organoratallic photochemistry of d3 and d6 natal ion complexes has becora large and diverse.ll’12 Chromium(III) is the model for the d3 natal ion system as a result of 5 6 intensive photoplnysical and photochemical studies. Studies in the d 13,14 natal ion system are numerous. Flash studies on cobalt(III)amrmine complexes show that redox reactions are the main pathways in aqueous solution and these complexes are most often used as quenchers for 2+,16 2+ 17 [Ru(bipy) and [0s(bipy)3 . Like coba1t(III), man,” 3] oeuium(II)19 and iridium(III)20 have also been used as redox quenchers. In addition, flash photolysis of Fen (TIM) L2 corplexes (an = 2,3,9,1o- tetranathyl—l,4,8,1l-tetraazacyclotetradeca-l,3,8,10-tetraene; L = NCS, 3cm or con 20 results in photosubstitution and linkage isonarizaticn. Ligand labilization results upon irradiation of the LP 21 imidazole , CH and CT bands of pentaammineiridium(II) complexes in aqueous solution. To date, the photochemical substitution reactions of osmium(II) 22 and platinum(IV) 23 have received little attention. Ecclusive photoaquation of py-X (4m 0 .47) results upon irradiation of the pyridine-substituted pentaanminerhodium (III) complexes . 24 The corbination of measured lifetimes of halopentaamminerhodium(III) com- 25,26 plexes in aqueous solution with the previous conclusion that intersystem crossing and internal conversion to the lowest energy LF excited state occurs with unit efficiency,27 allowed calculation of the individual rate constants for the radiative , nonradiative and reactive pathways.26 It was determined that photoaquation occurs 14—15 timas faster than the analogous ground state reaction. Ruthenium(III) anmines have been used for electron transfer quenching of nonemitting excited states28 and the reduction of copper in biological systems.29 I-kmever, the majority of the research has been involved with the ruthe- nium(II) complexes described below. Photochemistry of Ruthenium(II) Corplexes The photochemistry of various ruthenium(II) complexes with nitro— gen ligands, (e. g. [Ru(bipy)2L2]2+ and [RMNHB)5L]2+ where bipy = 2 , 2 ' -bipyridine and L = N—heteroaromatic ligands) has been investigated by both spectroscopic techrniques and photochemical studies. In 1960, Brandt3o reported the narrow band emission at 667 nm of [Ru(bipy)3] [C113 and assigned it to a 11* (mostly ligand) + (tzg) transition. The free 31 ligand emits at 426 on. Extensive investigation carried out on the complex allowed assignmant of the 667 nm emission as phosphorescence from the lowest MLCI' triplet of the complex.32’33 2+ 3] Complexes such as [Ru(bipy) and its derivatives have been subjected to a large nunber of studies34 and were found to be light stable,35 inert toward 36 substitution at ambient temperature in fluid solution , and lumines- cent in solution at room temperature as well as in a glass at low temperature. 32 In general , there is little wavelength dependence for emission35 and the complexes are exceptionally useful triplet sensi- 37 tizers. The excited state model by Crosby and coworkers treats the luminescent complex as a 4d5 Ru3+ core with three bipyridyl ligands, with the electron transferred into the lowest antibonding orbital of one of the ligands.32’35’36 38,39 Recent experimental evi- dence however pOints to the fact that the [Ru (bipy) 3] ,2+ once trought to be substitutionally inert, does undergo permanent substi- tution plnotochemistry. In contrast to the bipyridine ruthenium(II) complexes , pentaam- mineruthenium(II) complexes with N-heteroaromatic ligands such as pyridine are nonluminescent but exhibit wavelength dependent proto- chemistry. Sigwart and Spence40 reported that the oxidation of ruthe- nium(II) to ruthenium(III) was the principal photochemical reaction pathway for the pentaammineruthenium(II) molecular nitrogen complex, [Ru(NH3)5N2]2+. In 1969, Ford and coworkers41 found that the proto- chemical reactions of several pentaammineruthenium(II) complexes in aqueous solution included ligand aquation as well as oxidation of the ruthenium(II) to ruthenium(III) . For example, irradiation at the MLCI‘ absorption bands of pentaamminepyridineruthenium (II) tetrafluoroborate in aqueous solution resulted only in protoaquation (1) . This conclu— 2+ 2+ 407mm ‘7‘”7 mumflsmzo’] + W (aq. soln.) . [Ru m3) Spy] n_.+ cis- and trans-[Ru(NH3)4py (1120)]2+ + NI-13 (1) sion was based on the following observations: 1) the MCI band was regenerated after excess pyridine was added after irradiation. 2) ion- exchange elution of the photoproducts confirmed the spectroscopic quantum yields. 3) ruthenium(III) was not detected. Metal-to-ligard charge transfer excitation has been postulated * to lead to an excited state (MLCT) having an oxidized natal ion and a radical ligand in the coordination complex (2) .42 Two possible con- I — 2+ hv II 2+ [(NH3nsmu IN\ > 1 ——+ [(NH315Ru 5119)] (2) sequences of the (MLCT) * state are photooxidation of ruthenium(II) to ruthenium(III) and an enhanced reactivity of the pyridine ligand with electrophiles . However , it was found that photooxidation does not occur and studies with deuterium labelled complex showed that H-D exchange on the pyridine ring was low ( D m 0.001) . Further work43 has sl'own that the low quantum yield for pyridine aquation ( 4 m 0.04) from aqueous [Ru (NH3) 5py]2+ is essentially wavelength independent over the 254-436 nm range, suggesting conversion of the initially pepulated states to a cannon state. The quantum yield for pyridine displacenant on irradiation into 44 The theMLCI' band was found to be a function of pH in solution. quantum yield range of 0 . 04-0 . 075 was attributed to competitive acid- dependent and acid-independent reactions of a slort lived intermediate 37 on this or excited state. Flash studies by Natarajan and Endicott complex denonstated the presence of an intermediate with an acid - dependent lifetime. They prOposed an intermediate formed by rehybri- dization and protonation of the pyridine nitrogen to give a ruthenium (II) coordinated free radical species. To explain the mechanism of photoaquation, Ford ruled out the (MLCI')* state as the lowest energy excited state since low spin (15 ruthenium (III) ammine complexes are relatively substitution inert. 45 Radiationless deactivation to a "hot" ground state would explain the "19 ‘ '93.. . q} EL'I. l--. one; A‘ ‘ .ci V‘. i a A D 3 (C V ‘r ' it 5‘ \ Q a»... . ~‘F ~ F. . J. C m n “33‘ n K‘: n. 1 . "wi H" a“ competition between pyridine and ammonia aqua tion since the competition 46 occurs in the correSponding thermal reaction . However , vibrational relaxation is expected to occur at a faster rate in aqueous solution 43 and no wavelength dependence on the quantum yield is seen . Ford concludes that a ligand field excited state (LF) * populated from the (MICI') * is responsible for ligand labilization , since octahedral ruth- enium(II) has an electron in the 0* - orbital making it more reactive than the ground state. Charge transfer and ligand 1711* absorptions dominate the absorption spectrum so the presence of 61 LF state can only be inferred. For ruthenium(II) ammine complexes not dominated by MLCI' absorptions , LF bands are identifiable at wavelengths comparable to that of the [Ru(NH3)5py]2+ MICI' band. [Ru(NI-I3)6]2+ ”max = 390 nm, e 39 M'lom'l) and [Ru(mm3)5cni3cn~112+ (1m = 350 nm, e 163 M’lom'l) 47 undergo substitution ( 4: 0.2) in aqueous solution, consistent with the general observation that LF excitation of low spin (16 complexes lead to substitio‘n processes for the heavier transition metals . 48 Direct excitation into the LF state for [Ru (NI-13) 5py] 2+ plays a minor role due to the very large extinction coefficient of the MCI band (6: 7700 M’lcm'ln .42 The energy of the MLCI‘ band (Amax(CI')) of [Ru(NI‘13)5(py-X)]2+ is 49 very sensitive to the nature of the substituent X . The substituent x 3, C02-, (1)2013, CHO) cannot undergo its own chemical reaction. In aqueous solution. Ford observed that where (CH3, H, Cl, (1111-12, phenyl, CF )‘maxwm exceeds 460 nm, 4 was dramatically lower than for com- py-X plexes having )‘max (CT) of higher energy. A partial listing of the data in Table 1 shows that the range of ¢py—X spans more than three 50 orders of magnitude. Direct comparison of the (ppy-X values suffers o “a. a l .— 0‘.’ A. * :11 Li LA) .1» M. ‘E n‘mf‘o, 5“ .‘p‘ '1‘ “w ‘5 ‘ Yu ‘I . 1F|(‘ ‘t t"‘.’ from the fact that )‘irr is also a variable; however, additional studies showed that varying )‘irr did not change the relative order of q’py—X . From the data it is seen that the appropriate electron withdrawing sub- stituent leads to a reversal in the relative energies of the lower excited states to make a substitutionally unreactive charge transfer eXcited state lowest in energy. On the basis of these results, the following model was postulated. There are " reactive" complexes with nmxwr) < 460 nm presumably having a lowest energy (LF)* excited 49 Table l. Spectroscopic quantum yields for some [Ru(NI-I3)5(py-X)]2+ in aqueous solution . X )‘max (CT) , nm )‘irr' nm @py_x(spec) , mol/einstein CH3 398 405 0.037 H , 407 405 0.045 CF3 454 455 0.022 C(III3 523 520 0.00025 CHO 545 546 0.00005 state and "unreactive" complexes with )‘max > 460 nm presumably having a lowest energy (MLCT)* excited state. The energy of the MLCI‘ band is very sensitive to solvent and in cases where the MEET)“r and (1.1?”: excited states have similar energies , changes in the solvent alone may be sufficient to reverse the order of these states and thus change the reactivity of the complex . Whitten and Zarnegar51 investigated ruthenium (II) complexes of the . 2+ . - - type [Ru(bipy) an] [X] 2-n where L = 4-stllbazole and X = BF4 or PF6 . Here the substituent on the pyridine ring was an isomerizable double bond which may undergo its own protochemical reaction. These complexes do not photodissociate. Tlney echibit wavelength dependent luminescence and undergo wavelength dependent isorerization of the stilbazole double bond under direct or sensitized isorarization in butyronitrile (3) . a 1 2+ I 2+ 2 [ (bipy) 2RuI hi ] (3) Isonarization from the triplet state in the ruthenium(II) complexes is less efficient in cotparison to that observed for the free ligand ( Table 2) .52 Inefficiency is also evident when triplet sensitizers are used and The values range from 0.001 to 0.04. Whitten postulated that low energy irradiation produces a (MICI‘) * excited state which behaves like the radical anion of the olefinic ligarnd and results in preferen- tial cis to trans isonerization with the highest efficiency. High energy irradiation produces excited states with nearly an equal proba- bility of decay to the cis and trans ground states , appearing very similar in behavior to the free ligand.53 The autl'ors concluded that the wavelength effects are due to a rapid reaction of the upper excited 10 W Photokinetic data52 for the isonerization of the bipyridyl- ruthenium(II) 4-stilbazole complexes in butyronitrile. Airr’ nmn (ptrans-ncis ¢cis+trans % trans, pss 313 0.15 0.156 35 366 0.05 0.15 88 436 0.05 0.60 85 570 -- -- 88 366a 0.37 0.35 50 a4-stilbazole in benzene. 53 state and are not due to slow radiationless processes . Photochemistry of the Rhenium(I) Conplexes Metal carbonyl complexes are among the most photoreactive transi- tion metal complexes known.54 'I‘he excited state decay processes in fluid solution are dominated by ligand exchange and substitution. 55 Prior to 1972, the only metal carbonyl complexes known to luminesce were the low spin d6 tungsten, molybdenum and chromium complexes, which exhibited emission only at low temperature.54 56 W (CO) 5py exhibited ligand field (LF) absorption bands 6 Sec}?7 Wrighton, Hammond and Gray and LF emission in a glass with a 58'59 found that lifetime of 3 x 10 the derivatives of ClRe (c0) 3x, where x = 1,10-phenanthroline and related ligands exhibited emission both at 770K in glassy media and at 298°K in fluid solution. The variation in both emission band maxima and lowest absorption maxima with X arnd solvent polarity was consistent with a metal to ligard charge transfer (MET) rather than a ligand field (LP) transition. substantial triplet character was attributed to the ll * (MCI) emitting state from energy transfer experiments and the 6 emission lifetimes (10'5 sec at 770K, 10’ sec at 2980K) .59 Wrighton and coworkers60 found that complexes of XRe(CO) 3L2, where X = Cl, Br and L = tian_s_-3- and __tra_p_s_—4—styrylpyridine, have lowest energy absorption bards of intraligand nature. Irradiation of the styrylpyridine complexes into the lowest energy absorption band (313 or 366 mm) resulted in cis to trans isorarization of the coordi- natedligands with a quantum efficiency in the range 0.49—0.64 and stationary states that are to less than 84% cis. Triplet sensitization gave stationary states and quantum yields for the coordinated styryl- pyridines which were near tl'ose found for the free ligand.53 Little photosubstitution ( 4 rn+0.01) of the coordinated stilbene occurred The absorption spectra of XRe(CO)3Lz, where X = Cl, Br, I and L = 4-phenylpyridine, 4 , 4 '-bipyridine61 also have high energy absorption bands which are assigned to intraligandm.) mm* transitions and in addition have low energy bands assignned to Mncr transitions. The emission at 293°n< is attributed to a (Micr) * excited state having con- siderable triplet character. The emission at 770K intensifies, shifts to the blue and beconas longer lived. MLCI' character dominates the featureless emission spectrum for the 4 ,4 ' -bipyridine complexes. The appearance of structure in the emission of the 4-phenylpyridine complex shows that some IL mm* character is present. The 3- and 4-benzoylpyridine derivatives of XRe(CO)3L2, X = Cl, Br I,62 are also emissive at 77°K and 2980K. The broad structureless emission observed at 298°K with a lifetime of 10-6 sec is associated witlnthemcrtransition intheabsorption spectrum. At lcwtenpera— tures, the 4-benzcylpyridine complexes exhibited the usual effects: the 12 emission undergoes a blue shift, intensifies, becones longer lived 5 (4 x 10- sec) and remains featureless. The 3-benzoy1pyridine complex- es on the other hand, exhibited Imnltiple emission. The total emission spectrum exhibited some structure with a lifetime of 5 x 10-7 sec. Another long-lived, very structured component of emission was observed using a phosphoroscope attachment which allows observation of only long-lived emission ( > 1 ms) . The short lived emission at low tempe- rature was assigned to the sane (MLCI‘)* transition as that observed at 2980K. The long-lived structured emission was assigned to a slightly perturbed nnr* triplet state of the 3-benzoylpyridine and attributed to the fact that the lowest (MLCI‘)* and n1r* excited states are not thermally equilibrated at 770K. Wrighton and coworkers63 have used £a_c_- [SRe (c0) 3L] + [@3503] ' where S = CHBCN, Pl'nCN, pyridine, piperidine and L = 2,2'-biquinoline, 1,10—phenanthroline) to show that a variation in the charge density on rhenium(I) results in a variation in the energy of the (MLCI‘)* emissive state. For the 2,2 '-biquinoline complexes, no long-lived component of emissionwas seenat 77°Kandtheenergy of theMLCI‘state shiftto higher energy. An increase in the percent of long-lived emission correlates with the MCI band shift and is attributed to the increased * importance of the 1m triplet state. Photochemistry of Aromatic Aliphatic Ketones The photochemical reduction of aromatic alkyl ketones , both intranolecular and intenmolecular , involves the transfer of hydrogen to the carbonyl oxygen. The intramolecular photoreduction process is 64 the Norrish Type II reacti . The intermolecular photoreduction 13 process involves the abstraction of hydrogen from a suitable substrate to produce semipinacol and hydrogen donor radicals which proceed on to specific products dependent upon the reaction conditions. The energy diagrannin.Figure 2 represents the energies of the excited states with respect to the ground state of a phenyl alkyl ketcne. In solution, when a ketone absorbs light, it is excited to an * n 52(TT1T) _‘ . n: kic ‘ s ( 10* ' +— n l ____—— kisc T n k. 1c T( )* k 11"" f 2 * r > Reaction T1(nn) 5 k kd d k P Figure 2. Jablcnski diagram for a phenyl alkyl ketone. upper singlet state and then decays rapidly to the lowest singlet ll 13 -l)65 — 10 sec of the excited singlet state such as radiationless decay (kd) and 6 . excited state (kic m 10 The normal decay processes sec-l) are slow and rapid intersystem crossing ll fluorescence (kf m 10 occurs to the triplet manifold (kisc = 10 sec-1) , often with unit 66 efficiency. Emission frcnnthe lowest triplet state to the ground 14 state (kp) is known as phosphorescence . The Norrish nype II Reaction Aromatic alkyl ketones possessing gamma hydrogens on the alkyl side chain have been found to undergo cleavage to acetophenone and an alkene upon irradiation with ultraviolet light. This process, referred to as the Norrish ‘Iype II reaction,64 is an excellent monitor of the triplet state reactivity of ketones . 67 The accepted mechanism for the Norrish Type II reaction , proceeding through the hydroxy l , 4-biradical intermediate is shown in Figure 3. low quantum yields of acetophenone formation are often observed despite fast rates of gamma hydrogen abstraction . 67 By deuterium * 10 55.9% 3. Themechanismof the Norrish Type II reaction. 15 68 labeling, Coulson and Yang found that the gamma hydrogen atoms were involved in whatever decay processes were responsible for the low 69,70 quantum yields . Wagner and Hammond were the first to postulate that reverse gamma hydrogen transfer was occurring. As evidence, Wagner found that polar solvents and Lewis bases raised the total quantum yield to unity by solvating the l , 4-biradical intermediate and preventing reverse hydrogen transfer.71 Yang?2 was the first to identify the cyclobutanols formed in this reaction. Cyclobutanols have been found to generally account for 10-15% of the cleavage yields arnd thus allow for a reasonable estimate of their yield when direct 73 measuretent is not possible. The above polar solvent effects and observation of both acetophenone and cyclobutanols are consistent with the hypothesis that gamma hydrogen abstraction led to the formation 72 ,74 75 76 of a 1,4-biradical intenmediate. Lewis and others have been among those to provide evidence for the intermediacy of the l , 4-biradi- cal. Wagner and Zepp77 trapped the 1,4—biradical intermediate of Y-methocybutyrophenone using alkyl meroaptans . Solvents and substituents influence the reactivity of aromatic * * alkyl ketones by altering the energy levels of the n,1r and 1r,m * “'78 The n,m excited state involves triplet excited states (Figure 2) the promotion of an electron from the nonbonding orbital on oxygen to a m antibonding orbital. As a result, the excited state is electron deficient and radical-like in the proximity of the oxygen atom.79 The n,m* triplet excited state is said to be responsible for gamma hydro- gen abstraction and has reactivity similar to that of a te;r_t_-butoxy 80 radical. The m,m* excited state on the other hand involves promotion * of a m electron to a m antibonding orbital. While the exact nature of 16 * the 11,11 excited state is not clear,81 the electron spin is most likely localized on the aromatic ring82 and the carbonyl oxygen retains elec- tron rich. In many cases, the two triplet states are close enough to * equilibrate and the decreased reactivity when the m , 1r triplet is * lowest results from low equilibrium concentration of the reactive n , m 83 triplet state. Solvents affect the energy of the triplet state such that polar solvents stabilize the m, 11* triplet state relative to the n, m* triplet excited state. Substituents on the phenyl ring alter the energy of the triplet states and affect the reactivity of the triplet carbonyl toward gamma hydrogen abstraction. 83 Electron withdrawing groups raise the energy of the m , m* triplet excited state relative to the n,m* triplet excited state. Electron donating groups stabilize the m , m* triplet excited state with respect to the n , 11* triplet 84,85. excited state. Substituents on the alkyl side chain affect the rate of gamma hydrogen atom abstraction in parallel with their effects on C-H bond streng'th.86’8.7 Intermolecular Photoreduction Ciamuc' ' ian and Silber' 88 first observed intermolecular photoreduc- tion by isolating benzopinacol after irradiation of benZOphenone in isopropyl alcohol (4) . The early emphasis in photoreduction studies 0 0H OH OH 0 Ph/”\ Ph + oi3"\oi3—E’—+ Ph——-*—‘|——Ph + CH3)\CH3 Ph Ph (4) was on synthetic application since the pinacol products were prepared more readily arnd in higher chemical yields than by nonphotochemical methods. 89 The mechanistic studies conducted with photoreduction 90 have included hydrogen donors other than alcohols such as 17 91 92 93 94 tributylstannane , ethers , 97 95 hydrocarbons , anmines , sulphides , mercap’cans96 and phenols. Alcohols and alkylbenzenes are often the hydrogen donors of choice since the photoproducts are relatively easy to analyze. The intermolecular photoreduction mechanism involves initial bi- molecular interaction of the triplet ketone excited states with hydrogen donor (5) and the products which are isolated are dependent upon the reaction conditions . The photoreduction of benzophenone with “‘1 toluene gives the hydroxy radical and benzyl radical coupling products a in (6) , (7) and (9) .98 The irradiation of acetone with tributylstan- nane results in the formation of isopropyl alcohol , 93 according to 30* n KIR + EH ———'* FE + B' (5) RCR 1?ch + B'——————+ (6) (7) l B BB in RCR I + B' (8) 11‘. OH . we RCR+ICR————+ R (9) KER + Ketone of BH when (10) BB is an alcohol 18 reaction (8) . The irradiation of acetophenone with l-phenylethanol produced ketone, pinacol (9) and oridized the l-phenylethanol to acetophenone (lO) .99 At first it was thought that the oxidation of alcohol resulted from the disproportionation of the carbinol radicals . 100 ,101 99 However Pitts and later Cohen , found that optically active alcohols were not racemized when photolyzed with aryl ketones . The carbinol radicals are instead oxidized by ground state ketone as in (10) , consistent with the fact that ketone disappearance quantum yields approach a 'value of two dependent upon the reaction condi- tions. 102 The reactive state in intermolecular photoreduction was identified 103 from emission and quenching studies on compounds such as 101-104-110 as triplet benzophenone the accepted mechanism is an oversimplification. Experimental evidence has accumulated that 111 In 1959, Pittlel reported a colored, oxygen-sensitive intermediate for (4) which Back- stromn3 later assigned to a charge transfer complex of the hydroxy benzophenone radical and hydroxy isopmpyl radical . Recent work with compounds such as trifluoroacetcphenone has show that the first step in tlne photoreduction mechanism does not always involve hydrogen abstraction from the donor and is influenced not only by the substi- tuent on the ketone as observed for the Type II fragrentation but is also influenced by the donor itself.ll4'115 TrifluoroacetOphenone exhibits m,m* emission and reacts in one half the quantum yield obser- ved for acetophenone, yet its triplet reacts one hundred times faster than triplet acetone with toluene. The results suggest the following schete involving a primary charge transfer interaction (Figure 4) . This mechanism still allows for direct hydrogen abstraction and the new OH 2"?" CF3 FigEg 4. kCC l9 r_ Free radicals oc/ k p l i CH2 kd + kdiff PhOHOHPh\k:B\2CHZ CFCF 3 3 '1' Ground ___.., State Radicals The mechanism for the reaction of trifluoroacetOphenone with toluene in benzene , source of inefficiency (k_r) may lower (288' The involvenent of charge transfer in the photoreduction of trifluoroacetophenone with alkyl benzenes is well supported. The triplet state reactivities show a marked sensitivity toward substituents on the aromatic ring with a 117 negative 0 value. Donors without abstractable hydrogen interact with the triplets as efficiently as donors with abstractable hydrogen. The rate constants of triplet-donor interaction are not reduced by deuterium substitution . to C-H bond strength.‘u'6’117 117 The triplet reactivities are not sensitive 20 Photochemistry of Pyridyl Alkyl Ketones Wagner and Capen119 studied the Norrish ‘Iype II Fragmenntation processes for the n-prOpyl and n_n_-butyl pyridyl ketones in benzene and te_r_1:_—butyl alcohol solutions and found that the aza ring substituent had a definite effect on the excited state chemistry. The quantum yields of acetylpyridine formation for the pyridyl alkyl ketones were lower than those observed for the analogous phenyl alkyl ketones. Accompanying this decrease in efficiency of the pyridyl alkyl ketones was an increase in the triplet excited state reactivity (kr) in com- parison to the phenyl alkyl ketones. The energy changes of the n,-n* and (I , n” triplet excited states implied by the spectroscopic data could not explain the increases seen in excited state reactivity. A further discussion of the results and their implications is postponed until the discussion section of this thesis. Very limited studies have been carried out on the intermolecular photoreduction reactions of the pyridyl ketones . Early mechanistic studies focused on the migratory aptitudes of the alkyl and pyridyl groups in the pinacol—pinacolone rearrangerent of the acetyl and benzo- 120 yl pyridines. The decay kinetics of benzoylpyridine ketyl radicals were investigated by Nelson and Hayon using pulse radiolysis . 121 Finally, the photochemistry of di- (4-pyridyl)ketone in 2-propanol was studied in consecutive recording of absorption, emission, nmr and esr spectra during photolysis and the dark period . Derivatives of di(4-pyridy1)ketone and the isolated photoproduct di (4-pyridyl)methanol were synthesized and used to characterize the spectroscopically detected intermediates .122 21 Kinetics In order to understand the excited state processes , it is necessary to make quantitative measurements of the quantum yields , lifetimes arnd rate constants . The quantum yield for any photochemical process is the product of probabilities (11) where ¢ES represents the probability that the absorption of light produces the requisite excited state , represents the probability that the excited state will under- ¢R go the primary photoreaction required for process i and (pp represents the probability that any metastable intermediate proceeds on to ground state product. <1: (11) i = 4’25 ¢R¢P For the intramolecular hydrogen abstraction, the Norrish Type II process is described as follows: kr¢> <1’II = ¢isc¢BR¢P = (bisc r P (12) where ¢BR is the probability of l,4-biradical formation and ¢P is the probability that the 1,4-biradical will cleave to form enol and olefin. The experimentally detenmined quantities are (D. the lsc ' quantum yield of intersystem crossing; kr, the rate of gamma hydrogen abstraction and ‘1' , the lifetime of the triplet ketone excited state. By definition: 1 —=k-i-k+kp (13) r d 1.’ d sum of all pseudounimolecular forms of triplet decay which produce unu—ee where kp is usually negligibly small at room temperature and k is the nothing measureable. In the presence of an external quencher, Q, (13) 22 — = kr + kd + quQ] (14) where kq is the rate constant for quenching of the ketone triplet excited state. Using the value of <1> from (13) and (14). in (12) gives the Stern Volmer Equation (15)123 where no is the quantum yield in the absence of quencher. A plot of O/ versus [Q] gives a straight line <19 0 — = k T [Q] + 1 (15) q, q with the slope of qu. The value of kq is known for triplet quenchers 124 in various solvents, and the value of T is easily determined. Intersystem crossing yields were measured by ketone sensitization 125 of known triplet isorerization reactions . The efficiency of inter- system crossing wise) can be determined from the following: ——1——) (16) (Dc-rt kqn [Q] where a is the photostationary state _c_i_s_-tr_an_s ratio of the olefin quencher and (Dc-rt is the measured quantum yield for isorerization at that concentration. For intermolecular hydrogen abstraction , the excited state mechanism is similar to the Norrish Type II mechanism, except that product formation occurs after diffusion apart of the radical inter- mediates: 3K* + BH ——kr—-+ Radicals (HK' + B') (17) Radicals ——£—» Products (18) Radicals —l'—°i-+ K + RH (19) 23 Based on (11) , the quantum yield of product in the absence of quencher is: ¢Product = ¢' akrlBH] (20) krIBH] + kd and the product yield in the presence of external quencher is: d>. 01k [BH] = lsc r (21) kr[EH[ + kd + kqu] ¢Product (he obtains (22) by dividing (20) by (21) which in final fonm is identical to (15) , except for a different definition of '1': o kr[BH] + kd + kqu] = , = 1 + kqn[Q] (22) <1> krIBH] + kd l : = krlBH] + kd (23) Inversion of (20) indicates a linear relationship (24) between (n )'l and [Bfil-l. The slope of the line produced by the data plotted . . -l . . -1 according to (24) is kd(°‘¢isckr) and the intercept ls (noise) . Dividing the 510pe by the intercept gives k dlkr which can be substitu- ted into (23) along with the value of T determined from Stern Volmer quenching studies (15) to obtain the values for kd and kr. l k - = 1 l + d ) (24) d> (misc kr [EH] Research Goals The work to be discussed in this thesis is concerned with the intramolecular effects of metal coordination on the photochemistry of 24 ketones. From the foregoing description, it is clear that excited state behavior in organometallic complexes is influenced by the inter— actions of the ligands and their substituents with the central metal atom. The substituents on the ruthenium and rhenium complexes pre- viously stuiied are either nonreactive photochemically or undergo simple double bond isomerization. . The results suggest that reaction from an upper excited state is occurring. This is in contrast to the excited state processes in organic molecules , where reaction proceeds with few exceptions from the lowest excited state. 126 It is evident that the elaboration of the excited state mechanism in these and other organonetallic complexes rests in the selective quenching of the upper excited state in the excited state manifold. We reasoned that the use of pyridyl ketones as ligands would probe the mechanism of excited state behavior, the alkyl pyridyl ketone substituent acting as a moni- tor of triplet state reactivity . The main goal of this work was to find reactions from an upper excited state competitive with decay to the lower excited states . With the large nunber of photochemically active complexes to choose from, 127 the study was narrowed to those systems which already showed promise of observable excited state behavior. The relative ease of preparation and photosubstitution inertness of the pentaamminerutheniuMII) system suggested that this system would be best suited for a study using alkyl pyridyl ketones as ligands. The alkyl pyridyl ketone complexes of tri- carbonylrhenium(I) were also investigated after the observation by * 2 in 1978 of n,m' emission from the tricarbonylbrororheniumu) Wrighton6 benzoylpyridine systems . Initially, pyridyl alkyl ketones with gammna hydrogens on the alkyl 25 side chain were used as ligands for both metal systems and triplet state reactivity was monitored through the Norrish Type II reaction. Pyridyl ketone hydrochloride salts were studied as model complexes for the metal complexed ketones . The intermolecular photoreduction of the pyridyl ketone hydrochloride salts and pentaammnineruthenium (II) pyridyl ketone complexes was examined to oomplerent the intramolecular Norrish Type II photoreduction. The overall goal of these studies was to estimate the rate of internal conversion in the organometallic systems . RESULTS Pyridyl Ketones and Hydrochloride Salts Compound Preparation All pyridyl ketones were prepared by a Grignard reaction using the apprOpriate cyanOpyridine and haloalkane. The reaction gave high crude yields(80-95%) , but purification often was difficult since undesired reaction side products had boiling points within a degree or two of the desired pyridyl keyone . {Vista-substituted compounds proved the most difficult, 2—methyl—1- (3-pyridyl)butanone requiring both spinning band distillation and hydrochloride salt recrystallization to obtain a sample pure enough for photolysis(<0.5% impurity). The hydrochloride salts were prepared by bubbling hydrogen chloride gas through an ether solution of the apprOpriate pyridyl ketone . The salts were prone to decomposition and were often isolated in an inert atmosphere before storage in a vacuum dessicator at 0 °C . The ketones were stored under refrigeration; trace impurities (<0 . 5%) caused the initially colorless solutions to turn yellow. The compounds and their corresponding abbreviations are listed in Tables 3 and 4 . For enemple, 1- (4-pyridyl)pentanone is denoted as 4VP and 1- (4-pyridyl)pent— anone hydrochloride as 4VPHC1 . Intranolecular Photoreduction Photoproduct Identification All compounds produced acetylpyridene and an alkene upon 26 27 irradiation at 313 nm. A base impregneted gc column was used to con- vert the hydrdchloride salts to the free pyridyl ketone for analysis. The results were identical to those obtained by regenerating the free pyridyl ketone using anhydrous potassium carbonate prior to analysis. 128 The pyridyl ketone was identified by comparison of the gas chromato- graph(gc) retention time with an authentic sample. The small peaks observed before and after the unfragrented ketone were assured to be the expected cyclobutanones73 and account for 10-15% of the cleavage yields . Attempts to isolate these compounds by preparative gc were unsuccessful. A yellow color119 appeared only when 213p, 2vn> and 33p were irradiated. The color was most intense upon prolonged irra- diation especially in polar solvents , and least intense in the presence of high querncher concentration . The color disappeared when the solu- tion was exposed to the atmosphere . For ZBP , competitive gamma hydrogen abstraction by the pyridine nitrogen is possible, as observed for pyrimnidyl ketones.]'29'130 An additional product peak appeared upon irradiation of the meta-substituted compounds , but attempts to isolate the compound by preparative gc were unsuccessful . Quantum Yields Quantum yields for photoproduct formation were obtained by 131 at 25°C . irradiation at 313 mn in a "rrerry—go-roun " apparatus Solutions containing various concentrations of ketone , often in the presence of various concentrations of additive , were irradiated in parallel with 0.1 M solutions of valerophenone actinoreter in benzene. The 4,11 for 0.1 M valeropheneone has been measured as 0.33 in benzene ~< - o l' (I (I) I! I‘ll 28 solution132 annd all quantum yields are reported relative to that value. Quantum yields were measured at less than 5% conversion for fragtenta- tion studies arnd 20% conversion for ketone disappearance studies . All quantum yields are listed in Tables 3 and 4 . Quantum yields ”max) were measured in benzene solution containing 1 . 0-8 . 0M _t;_er_t_—butyl alcohol . Increasing the concentration of art-bu— tyl alcohol caused the quantum yield to rise until it reached a maximum value, at which point it leveled off or slowly decreased.132 Representative plots of quantum yield versus t;er_t-butyl alcohol concentration are shown in Figures 5 and 6 . The free pyridyl ketones show a greater variation in quantum yield than the pyridyl ketone ’ hydrochloride salts over the alcohol concentration range . The maximum quantum yields for the pyridyl ketones approach unity while the quantum yields for the pyridyl ketone hydrochloride salts are much lower (0. 12— 0. 42) . Figures 7 and 8 demonstrate the effect of varying ketone concen- trations on quantum yields . Plots of quantum yield versus ketone con- centration were linear. The positive slope of the line varies both 119 and alkyl side chain. The free pyridyl ketones with aza position show a greater concentration effect than the pyridyl ketone hydrochlo- ride salts . The values extrapolated to zero ketone concentration are contained in Tables 3 and 4 underthe heading or. The on value is enhanced by the addition of 2% water to the acetonitrile (Table 5) . Various additives (zinc chloride , rhenium (I) and ruthenium(II) complexes) decreased 4’11 as illustrated for 4VP 29 2.: I one I end one oeeflacfiooa ER. \ / nice. .ee e.e cice.c.cm.c mm.c c.~e.c. cm.c u.e~.c. mm.c ocwncmm II 3.8 I etc I nee one oeafiaaduocs ER. \ / use m.m~ so; uAEéQe caterers name. cad uses 85 opossum II o mmecm I he I one 85 weafleéumoa are. \ /z use I 25 $5 mmd one mfinfim 0 mouse I he I has one mfifigmos 8mm. \ / use: I 2.0 $5 35 name. 35 ofinsom I. 0 Sign I so I 35 has weefiasouooa 3mm. \ / 7.22m I .25 $5 3.6 one ofinsmm I. o z o one 0 some I. o T2; 6. c .e 3e be e e be ”.838 c8860 c. 8.391 ascend was wow 38 qflwquouofi . m manna 3O e.cam.~ I en.c I ec.c mm.c oeauueccumos III Teams; I one 35 Re moo 08.2mm / \z o a.cae.ee I I I ec.c cc.c weeuuecoumos ia>au2ac .II I I I so Se £6 2028 / \z o mu.ece I em.c I an.c ce.c unsuneocuuus aanmmza. III .ca I e~.c ee.c ,ee.c em.c monsoon ,/ .\ o m.caa.e I mc.c I ee.c me.c meauueoosooov insane». .II scene I mic med as mac 88:8 / \ 0 ea eu.ce I mm.c I He.c cc.c oaauueccuous .a>e. II. ms t m e me o use. 83 c use 28 c ham 8 mm c came. m~.c sponsor / \z c U 8H 0 .. X2 XI 0 72:» x e 8e ., 0e e be £838 @5098 .6383 m mecca .m manna. 31 I ed a TR 85 3.0 3.0 ~85 sesame. . (Ho \ / I N a .me 3.0 No.0 mm.o mmé Sofimfl l.z O IHU \ / I m H .3 :6 3.0 Hmé 35 Summmm. z o o o 0 can Mn Ts o; r T: c; 6. ea c e e be c.5098 c. Benn 8302082: 889. 3.38 9t sou flop beings . e manna. .m: .wmmm .stucgo magfisomImJImcmnu osm (Mam . 8333963 wcweomuedmnm . H game . 3:0on aging mo monomono m5 5 éuaamumom mo 3.3.» enhance cesarean .uficflsaesumoo no 8398c of non canes Shaman .a: man no confines .889. 2 me. on Tchtbov .m mason. 3.3 3.0 H 3.3 3.0 mm.0 m~.0 m3.o AHUwEmmmzm. I mmé 3.0 8.0 mud 3.0 “Hummermmz: . \ / o mz+ I8 m0.m m.0 M has mm0.0 3.0 0m.0 3.0 39533 \ /+zm 0 I30 \ / N.m mmé «Nd no.0 no.0 had 38%. II I o +2e 2 3 I v6 3.0 3.0 mm.0 3.0 3%. o o 0 came VT s 72w e 6. 72c; x 8e 0 e e be 950960 .7928. .e manna. 33 50500000 BBHOm 3; .5393 98303§Im.3 «0 0.5009: m§Im3 030 . 3030030“.v 3.3050193» m0 gammum 0nd :3 “83303333me m0 303.3 35580 gunman _ .mfigummaumom m0 0030053 05 00m 30303» 5030 .50 m3m um Egg 6335303000 5... 830x 2 mod—n.v 0.m m3.m 3.0 3.0 ~N.0 m3.0 30E>¢mzt \ /% v.3. I 3.0 3.0 ~m.0 03.0 3953. \ / :0 .930 0 x9. x... 3uzm x 3:20 x 89 o e e no 050950 A.©.#§v .v 0H3 33 a 1.0- U r v I t 4 6 8 1o [tert-butyl alcohol] , (M) Figgge 5. Effect of concentration of tertébutyl alcohol on quantum yield of acetylpyridine fonmation for 2VP([D), 3VP(JL), 4VP(.), mono), mum and 4vmc1qj). Formation of acetylpyridine:monitored. PLEASE NOTE: Page 34 is missing in numbering on1y. Text follows. FiImed as received. UNIVERSITY MICROFILMS 35 0.7~ 0.6d 5 '4 0.5“ r‘ (fr . 11“ ." D D “a / O I. W, 0.4. I “’11 0.3- 0.2 .1! I W I: T I 4 6 8 10 fl - [tert-butyl alcol'nl] , (M) F1913 6 . Effect of concentration of tart-Ml alcohol on quantun yield of 4-acety1pyridine formation for 4BP (.) . Wit-34W (A) , 4VP(U) and MEMO). Fonration of 4-aoetylpyridjne mnitored. 36 0.9- I 0.8« A 0.7- . A. A u L) 0.6- D 0.5- 4’11 0.4« 0.3~ 0.2a“ 0.1-1W I T f 1 T' 0.04 0.08 0.12 0.16 0.20 [Ketone] , (M) Fig 7. Effect of mentration of ketone on quantmm yield for 2VP(A), NH.) and 4VP(D) in acetonitrile; 4VP(O) in benzene and 4VPHC1(.) in acetonitrile. Formation of acetylpygidine monitored. 37 0.9: 0.81 0.7% 0.6~ 0 II 0.5: 0.4‘ j 0:04 0:08 0:12 0.16 0.20 [Ketone], 00 Fig 8. Effect of concentration of ketone on quantun yield for 4BP (0), 4VP(D) and yMe4VP(A) in acetonitrile; 4139(0), 4VP (II) and yMeQVP(‘L) in benzene. Fermation of acetylpyridine nomitored. in Table 6. The error associated with the quantum yields was detennined by carrying out at least one duplicate runs per ccmpound and was found . to be 15% for acetylpyridine quantum yields and 1.10% for ketone disappearance quantum yields (0_ Table 5. Effect of water on the quantun yield of 4-acetylpyridine for l- (4-pyridyl) pentanone in acetonitrile. %water U'IIl-?-0\Jl\Jl'--'| ¢4AP 0.57 0.58 0.54 0.50 0.47 Table 6. Effect of various additives on the quantum yield of 4-aoetylpyridine for l- (4-pyridyl) pentanone . Additive a ZnCl2 a ZnCl2 ZnClza none Additive [Ru (NH3) spy] [BF41 2a [Ru(m3)54v1>1 [013,12a BrRe (00) 5b BrRe (00) 3 (4VP)21D a [4VP] : [ZnC12] <1) acetonitrile solvent . bbenzene solvent . g 0.16 0.15 0.14 0.23 Absorbanoe 4VP : Absorbance Additive ¢4AP 2 : 1 0.11 2 : l 0.12 2 : 1 0.042 2 : 1 0.061 39 Quenching Studies Stern Volmer quenching studies were performed by the 313 nm irradiation of 0 . 05 M ketone solutions containing varying amounts of quencher . The concentration of photoproduct , normally an acetylpyri- dine, was determined using the area ratio of product : internal standard described in the Experimental Section. A cis, trans mixture of 1,3-pentadiene was used for the studies in benzene. Ethyl sorbate and 1 , 3-pentadiene gave identical results in acetonitrile . Ethyl sorbate was used in acetonitrile solution when high quencher concentra- tion was required because of its greater solubility. Conversions were usually kept below 7% for the tubes without quencher and slopes were linear out to 00/0 values of 6. Duplicate quenching runs indicate a 15% error in kg“: determinations. Values of kq-r are listed in Tables 3 and 4 . Representative Stern Volmer plots are presented in Figures 9 and 10 . Intersystem Crossing Studies Intersystem crossing yields were determined by parallel irradia— ticn at 313 nm of 0.05 M ketone solutions containing varying amounts of gig-l , 3—pentadiene and 0 . 1 M acetophenone solutions containing 1 . 0 125 M cis-1,3-pa'1tadiene. The concentrations of cis- and trans-1,3— pentadiene isaners were determined by gc analysis. Plots of 0.55( c+t) '1 versus quencher concentration were linear as shown in Figure 11. Irradiation of the pyridyl ketone hydrochloride salts with _ci_s-l , 3- pentadiene was accanpanied by a carpeting reaction producing a white precipitate and a product obscuring the 9_is_- and £r__ans_-l , 3-pentadiene gc peaks. 01:) 3.} ,. ‘0‘“ N 40 5.0% 2.0- A 1.0 i \‘ 0.0 4 0.01 0102 0.03 [c_ig-l ,3-Pentadieie] , (M) Fig 9. Stern Volmer plot for BMe3BP in benzene(O); BMeBBP(.) , 3BP(A) and 2VP(A) in acetonitrile. Formation of acetyl- 41 0 (‘D ., on) 3.0 " 2.0 - [A 1.0 0.0 0.2 014 0:6 0.8 1.0 [Ethyl sorbate] I (M) F193 10. Stern Volmer plots for 3VPIII1(O) , warm.) , BMeBBPIIII (A) and ywmlm) in acetonitrile. Formation of acetylpyridine monitored. 42 1.6+ 1.5- 0.9 ' I 1—‘ a 0.0 '0.5 1.0 1.5 2.0 [cis-1,3-paitadime] -1. (M) '1 Figure 11. The saisitized isanerization of gig-LB-pmtadiene by 4VP(O) and 3VP“) in baizene. 43 Intermolecular Photoreduction Phot0product Identification In all cases the photoproduct resulting from the hydrogen atcm donating substrate was analyzed for the kinetic studies . Fonnation of acetone, 2,3-diphenyl—2,3-butanediol, bibenzyl and 1,2-di-p-tolyl— ethane was detected by comparison with the go retention” time of authentic samples . Irradiation of the acetylpyridine hydrochloride salts with toluene produced bibenzyl . Irradiation of 3APHC1 and 4APHCl with p—xylene in acetonitrile produced 1 , 2-di-p-tolylethane and a white precipitate identified as the pyridyl ketone hydrochloride salt pinacol . Irradiation of 3APHC1 with l-phenylethanol in acetonitrile produced a yellow colored soluticm containing acetOphenone and a yellow oil assured to be the pyridyl ketone hydrochloride salt pinacol . Irradia- tion of 4APHC1 with l-pheny] ethanol in acetonitrile produced aceto- phenone _and a white precipitate identified as the pyridyl ketone hydrochloride salt pinacols . AcetOphenone pinacol was not detected in the l-phenylethanol studies . Irradiation of 3APHC1 and 4APHC1 with 2-propano1 in acetonitrile produced acetone and the pyridyl ketone hydrochloride salt pinacols . giantun Yields Quantum yields for acetone , acetOphenone and l , 2-dia-p—toly1ethane formation were obtained by the parallel irradiation of degassed samples in acetonitrile and 0 . 1 M solutions of valerOphenone in benzene at 313 min the "Irler'ry-go-romd" apparatus at 25°C.131'132 The samples contained 0. 01 M pyridyl ketone hydrochloride salt and either 0.0125-l.0 M 2-pr0panol, 0.1—0.5 M l-phenylethanol or 0.5-2.5 M p—xylene. All quantun yields are corrected for total absorbance of 44 light by the pyridyl ketone hydrochloride salt . Percent conversion was 5% or less and product/ standard area ratios were obtained by gc analysis. Plots of 0-1 versus [hydrogen donor] -1 were linear (Figures 12—14) and values for the slope and intercept are listed in Table 7. The plot of quantum yield of photoproduct formation versus [4APHC1] was linear. ‘ Quenching Studies Stern Volmer quenching studies were performed by the 366 nm irradiation of a 0.01 M ketone solution containing a constant amount of hydrogen donor and 0.0015-0.015 M naphthalene in acetonitrile. Conversions were kept below 7% for the tube without quencher and slopes were linear out to 00/0 values of 2. Duplicate quenching runs indicate a 15% error in qu determination. Values for qu are listed in Table 7 and the Stern Volmer plots are presented in Figure 15. Table 7 . Photokinetic data for the intermolecular photoreduction of the pyridyl ketone hydrochloride salts in acetonitrile . a 1 Ketone Donor Slope Intercept kq‘t , 'M' b 4APHC1 p—xylene 170 . 2 . 5 - 4API-IC1 l-phenylethanol 5.9 1.8 6.3-18.5C 4APHC1 2-pr0panol 1.2 1.8 34 1- l“:1 3APHC1 l-phenylethanol 6 . 0 2 . 3 - 3110001 2-propanol 6.4 1.2 56 1 2e 30.01 M ketone, irradiated at 313 nm, all slopes and intercepts analyzed by least squares. b366 nm, naphthalene quencher. C:[l-phenyl» ethanol] = 0.4 M. d[2-propanol] = 0.376 M. e[2-propanol] = 0.67 M. 45 240 - 200 - 160 - 40" j I l. 0 2. 0~ [pg-xylene] '1. (M) '1 Fig 12 . Dependence of quantun yield of 1 , 2-di—p-toly1ethane (DIE) an p—xylene concentration , 4-acety1pyridine hydrochloride in acetonitrile. Fomation of DI'E monitored. 46 60- 50- 20- " ’0 10- . 2 4 6 8 10 [l-phonylethanol] -1 , (M) -1 HE 13. Dependence of quantum yield of acetophenone formation on l-phenylethanol concentration in acetonitrile , 4-acetyl- pyridine hydrochloride (0) and 3-acetylpyridine hydro- chloride. Fontation of acetophenone monitored. 47 12 - O 10 ‘- 3.. -l ((bacetone) ’4 6... O ’0 4~ ’4 . O '3. 24 F l r f 1— 1 2 3 4 5 [2-pr0pan01] -1, M-1 Fim 14. Dependence of the quantum yield of acetone formation on 2-propanol concentration in acetonitrile , 4-acetyl— pyridine ide (O) and 3—acetylpyridine hydro- chloride( ) . Formation of acetone monitored. 48 1.7- 1.6‘ r 1.5. ’ 1.4 '- no) (0) 1.1 - A T I ' 0.004 0.008 0.012 0.016 [Naphthalene] , (M) F1935 .15. Stern Volmer plots for m in the presence of 0.4 M 2-prOpanol(O) and 3APHCl in the presence of 0.66 M 2-pr0panol (.) in acetonitrile solution. Formation of acetone monitored. 49 Product formation is not quenched by 0 . 04 M naphthalene upon irradiation of 0.01 M 3APHC1 with 0.1-0.5 M l-phenylethanol and 0.01 M 3APHC1 and 0.01 M 4APHC1 with 0.3—2.5 M p—xylene. Formation of 4APHC1 from 0.01 M 4VPHC1 is quenched by 0.03-1.1 M p-xylene with a kqn value of 1.69. The formation of 4APHC1 from 0.011 M 4VPHC1 is not quenched by 0.01-1.4 M benzene. Formation of 4M> from 0.012 M 4VP is not quenched by 0.0-0.4 M p—xylene. Spectrosc0pic Studies The absorption maxima are found in the Experimental Section, while the molar absortivities (e) and triplet energies (ET) are listed in Table 8 . Corrected phosphorescence spectra (see Experimental Section) were obtained at 770K in ethanol and a 5:1 mixture of methylcyclohexane 2-methylbutane. Emission spectra for the pyridyl ketone hydroclnloride salts were obtained at 770K in ethanol. The compounds do not emit at room temperature. Concentrations of pyridyl ketone were approximately 1 x 10“1 M. The triplet energies of the butyryl pyridyl ketones lie .3 kcal higher in energy than the valeryl pyridyl ketones. This situa- tion also exists with the phenyl alkyl ketones where FT (butyrophenone) = 74.5 kcal and Er(valerophenone) = 71.8 kcal.134 The lack of change of triplet energy with solvent polarity for 3VP and 4VP was previously observed with valerophenone. 134 Representative emission spectra of the pyridyl ketones and corresponding hydrochloride salts are seen in Figures 16-18. The spectra obtained in ethanol are less structured than in the hydrocarbon solvents . The triplet energies of a given pyridyl ketone and its corresponding hydrochloride salt are very similar. 50 .05. n 0....3958 5 8002883 8888233034.; “T1353"... on All. 0§§§§§30m03§g 38 c3 0§§3§HEI$I3 .45 Scam oQEomouQfimoom .03 Magda ea . 51.08353 0mm 00m 0a.:4 00v e _ . 2mm worsens 9mm 82mm £121:th Uh? 51 it. u ....... 0 305.50 5 03003200030»: 0§55d3>oflualmv I3 2.. .. 10398.30 och TL 0§£§FNH0§03053§ 35 c3 00003523§§1m013 m0 0.300% 0088890m0£m . 3 gem ea . @8396: 0mm 00m 0mv 00v sum LIE-Imam 'KnISIBnUI nonssmo moaned 52 omm — 35 um gfiaflgm ”m§03%3§ 3um :3 wcocmpcwafimgnalmv I3 mo firflbmmm 8588332,“ .3 a: . a: . 5553935 00m Omv Ow? 91min Mentm 'KQ'FSUB‘JUI LDTSS‘FIIE mum 53 Table 8 . Spectroscopic data for the pyridyl ketones and corresponding hydrochloride salts . Ketone Absormion Emiss ion Acetonitrile Benzene 6313““? M'1 "'1 €313nm’ M’len'l ET, kcal/mol ZAP 77 (85) 74 70.9d 70.9C'd zap 54 (78) ' 51 75.2 zvp 62 (93) 41 71.9 Y.MeZVP 76 (53) 58 71.8 BAP 51 (38) 49 71.1d 73.1‘1'e BBP 47 (70) 4o ‘ 74.5 BMe3BP 57 (97) 42 72.2 3VP 57 (44) 47 73.6 73.6C 4A? 90 (58)- 147 69.5d 70.36"e 4BP 88 (61) 88 - BMe4BP 88 (57) 125 - 4VP 92 (65) 125 71.9 71.0C Me4VP 102 (70) 207 72.4 3vpuc1 (44) ' - 73.4C 4VPHC1 (65) - 70.8C aNtrrber's in parenthesis refer to the corresponding pyridyl ketone hydrochloride salts . 195 :1 methylcyclohexane: 2-methy1butane unless otherwise noted. cEthanol. dReference 133. eReference 133, 1:1 ethanol :methanol . Ruthenium Catplexes Preparation and Identification The method of choice for the synthesis of chloropentaanmine— rutheniuMIII) dichloride is shown in (25) . The substituted pyridine pentaamninenltheniuMII) ocmplexes were synthesized by dripping an aqueous solution of [Ru(NH3)5Cl] [Cl]2 through a zinc mercury amalgam 'ri LT 54 oolum into an aqueous solution of excess ligand. The ruthenium(II) oanplex was then precipitated as the tetrafluoroborate salt (26) as detailed in the Ebcperimental Section . High crude yields were obtained A [mm3)6][c113 + ml or [RU(NH3)5C11 [C112 (25) H20 [Ru(NH)Cl][C1] + N— zn'Hg thumIi)N_ JIBF] 35 2 \ may 35\ x 42 4 4 (26) but great losses in complex resulted on recrystallization. The outplexes are stable when stored under argon at 0°C . Synthesis using granular mercuric chloride for the zinc mercury amalgam gave pyridine and pyridyl ketone pentaanmineruthenimMII) catplexes with A max of the MLCT band matching the literature values (m = 7700 M‘lcm'l) .135 [Ru(NH3)5py] [BF412 gave the correct elenmtal analysis while unsatisfactory analysis were obtained for th' valerylpyridine pentaamniner'utheniun (II) ocmplexes . The paitaanmine- pyridine ruthenium(II) tetrafluoroborate ccmplex was easily recry- stallizable while great product loss accompanied the increase in actinction coefficient of the MLCI‘ Anex (ex. Ru4VP: 8 increased 1 503 nm fran 7700 to 9680 M- art-1) on recrystallization of the pmtammine- rutheniuMII) valerylpyridyl ketone complexes . Chly the Egg-valeryl pyridyl ketone ample}: gave microfine crystals and the best elanental analysis of the ismers. Synthesis using powdered mercuric chloride for the zinc-mercury amalgam gave pyridyl ketcne pentaanminenrttmiun (II) complexes imnediately having high extinction coefficients for the Amax MLCT 1 band (i.e. Ru4VP: e = 11400 M' cm‘l) and recrystallization had 503 nm 55 no effect on the Am MLCI' extinctim coefficient. Elemental analyses gave the correct percentage of carbcn but were sane-what low in hydrogen and nitrogen . The nmreproduceability in duplicate analysis of the same sample and 1- 0.4% range are indicative of the problems in canbus— ticn of the pyridyl ketone pentaatminenrtheniuMII) canplexes. Other workers experienced similar problems, eg. [Ru(NH3)5NCR]2+ where R = 1 2+ 137 - 36 CH3, c6115, ((112)4coo andai=cnca3, [Ru(NH3)SCSH4NCHol , and 2+ 138 [mCNH3)55(/“\ 412(3350) 258(3750) 223(6740) 260 (RuBAP) 0 [mm3)5<:/>/U\/l\ 415(4700) 259(6020) b 55 (W33?) 412 (4705) 259(5330) 277(7715) 65 0 N... [Rum-13) 5§>/'K/\/412 (4460) 257(4780) 223(9995) 330 (Ru3VP) 0 [Ru (M13) ESQ-A 510 (11450) 266 (4035) 260 (R114AP) [Ru (m3) SNW 506 (9820) 266 (3350) 218 (7000) 250 arranger) [Ru(NH3)§fi<;:;>>’ji‘\wl"\~r’5o3(11400) 268(2980) b 32 (Ru4vp) 519(10220) 266(3095) 223(6020) 31 ___ <3 [Ru(NH3)50g;:;>V’JK"”\‘T”sos(9220) 265(3690) 4o , 519(9970) 267(3020) 222(5560) 39 (mm) Wufle solvent unless otherwise noted. bAqueous solution . .ofiflafiuooc 5 as... 038286»; 8836216034.; 2 TS x on can Ti. floccufiozsoflsousue -3 x an no shaman Snot—once .3 yuan z -3 x an . Tl Sena :coocfiamnzsoflsnusdmmgam. 2 v v a: .fic53>§ com com oov 57 I m.o 58 6332888 ea Ti moanoatonosr ococfifinseaoflscucue z (3 x m; can Tioficfifieaoflscaeé a T2 x 3 .Tl flame :macesaaioflaééml sea. a E: . 5653m>m3 oom cow ‘6‘. ....... d ' o’ O ....... coo-00' Y3 x mg no 60.0.ch 830g .8 shaman ...3.o memo remade .. v.0 I mCO r v.0 . >6 59 6352886 5 T-.. occafiooeioflsoneua 2 can TI. Nana _loaafiaissoflaaéhemlmszeae 2 m1 o3x3 much x H no 808% coaccaomhc AN swans Es 5583963 08 com owe com d u d 1 -2 c c I ’ n a . a i c . nan—IO" ---- ’ a“‘“' TIE e . Ti: TS x HA no 0302886 Ba (2 x me no 8338 msoooon on «team: :mfioahscsmlmrzscfi no chosen coahchonha .mm amuse com 0 E: .5553963 oov oom pl) — )II/ \II J 0.0 .II \\\ 1”! I \\ / II \\ I 1 HQC ’ \ I z s a z s a \ x a N c .m s as . . e . m . a m o I O . e s e To we r s .A a e . N . s s m o v I s s a; a m5 .a sx x e . fie ’(N .. m6 61 infrared spectra of the ruthenium(II) coordinated pyridyl ketone canplexes exhibit a broadeiing and shift to lower frequency for the carbonyl stretch (Table 10) . Represeltative infrared spectra are shown Table 10. IR band in the CO stretching region for the pyridyl ketone pentaanminerutheniun (II) tetrafluorcborates . Canplex VC=O'b cm.-1 (a) RuZAP 1667-1676 (1701) W 1666-1685 (1690) Ru4AP 1662-1673 (1700) RuZVP 1667 (1697) RuBVP 1665-1682 (1685) Ru4VP 1672 (1698) R11 Me3BP 1674 (1689) Ru MBP 1672 (1693) R11 MVP 1660 (1695) aNurbers in parenthesis refer to the corresponding free pyridyl ketones. bKBr pellets. in Figures 23 and 24. Cathex stability The pyridyl ketme ruthenium (II) canplexes are extrenely stable in terms of thermal ligand dissociation. When analyzed by go, no dis- sociation of the pyridyl ketone ligand frcm the couplex is seen up to injection port tauperatures of 250°C . Dissociation does occur at injection port tenperatures greater than 280°C, but it is not quanti- tative and the peaks are broad in canpariscn to the free ligand: Injection port tetperature: 250°C 280°C 320°C Maximun fragmentation: 0% 18% 25% 62 -20- 3500 3000 2500 2000 1500 -80- -50- -4o- -20- 1300 1600 1900 1200 1000 800 Frequency (an-1) Figure 23. Infrared spectrun of [Ru(bni3)5pyridine] [BF4]2. 63 -50- -40- 3500 3000 2500 2000 1500 -60- 41 l L J l _l 1800 1600 1400 1200 1000 800 Frequexcy (cm-1) Figure 24. Infrared spectrun of [mm3)5(l-(4-pyridyl)pe1tana1e)] BF 4 2’ 64 Chemical methods to quantitatively fragment the ccmplex were attempted prior to analysis. Solutions of the complex in both acetonitrile and butyronitrile were refluxed in the presence of excess triphenylphos- phine or lithium chloride. This resulted in only 1% ligand fragmenta- tion and was accanpanied by a solution color change. Solution stability of the pyridyl ketone peitaanminerutheniun (II) pyridyl ketcne complexes was assessed by examination of the absorption spectra. The spectral changes which occur for dearaeted aqueous and acetmitrile solutions of pentaammine [4-methyl-l- (4-pyridyl) pentanone] rutheiiuMII) tetrafluoroborate (ybeRu4VP) are presented in Table 11. Table 11. Solution stability of pentaanmine [4-nethyl-l- (4-pyridyl) pentanonelrutheniumul) tetrafluoroborate. Aqueous solution:a A , nm ( e, M-lcm-l) max original solution 518(10135) 267(3150) 223(5875) in dark, 24 hr. (cold) 519( 8430) 268(3400) 221(5550) in dark, 24 hr. (rm.T.) 516( 7060) 263(3120) 217(5455) in light, 24 hr. (rm.T.) 515( 1329) 317 (3030) 287(3155) 217(7450) Acetcnitrile solution:b original solution 505(9995) 266(2285) in dark, 24 hr. (cold) 503 (7665) 265 (2160) in light, 24 hr. (rm.T.) featureless in visible 265(2065) ,aIRuyMe4VP] = 1.5 x 10'5M. blRuyMe4VP] = 1.04 x 10’514. Wheu kept in the cold and in the dark, acetonitrile solutions are nore stable towards pyridyl ketme ligand dissociation than are aqueous solutions. Upon eqzosure to daylight, the Optical deisity at the MLCT Am gradually decreases for RunAVP (Figure 25) . The position of the 65 0.91 0.81 0.7‘ 0.6‘ 0.5' 0.4‘A 0.34 0.24 f 0.1- WW Optical demsity ———-+ 300 400 500 600 - Wavelength, nm 1.04 0.9‘ 0.8‘ 0.4J 0.3' \‘ o.2~ (\‘\ 0.1+ \k’ -1 I I l 300 400 500 600 Wavelength , nm Figure 25. Solution stability upcn exposure to light of RuyMe4VP in: A) aqueous solution. B) acetcnitrile solution 66 MLCI‘ band Changes little in aqueous solution and undergoes a blue shift in acetonitrile solution; in both cases the optical density gradually decreases. All the pyridyl ketone ruthenium(II) camplexes which were synthesized undergo the same type of decomposition illustrated here . The changes in MLCI‘ band position and absorbance at the MICI‘ Amax upon irradiation at 313 nm are listed in Table 12. All the camplexes under- go the same photochemical decomposition illustrated here. Table 12. Photochemical stability of pentaammine[4—nethyl—1—é4- pyridyl) pentanone] rutheniun (II) tetrafluoroborate . Time, hr. Amax’b nm Absorbance )‘max'c nm Absorbance 0.0 . 519 0.619 505 0.719 2.0 518 0.563 499 0.532 4.5 518 0.473 490 0.317 6 . 5 517 0 . 368 475 0 . 105 18.0 517 0.246 460 0.072 5 alRuyMe4VP] = 1.49 x 10- M in aqueous solution, 0.00017 einsteins/hr. °[myMe4VP] = 1.05 x 10'5M in acetonitrile, 0.0097 einsteins/ hr. C )‘irr = 313 nm. Intranolecular Type II Reaction Photoprcduct Ideitification Upon irradiation at 313 nm in acetonitrile solution all complexes produced alkene and same produced pyridyl ketone. The alkene produced in the irradiation of the ruthenium(II) pyridyl ketone complex was identified by camparison of the go retention time with alkene produced by the irradiation of an moanplexed pyridyl ketgle sanple. The alkene cmcmtraticndetemunedbytmsmetmdwasfomdtobewithini-3%0f 67 the acetylpyridine camcemtratim determined under analysis conditions for low ketone concentrations . The pyridyl ketones produced upon irradiation of the ruthenium (II) pyridyl ketone carplexes were identi- fied by comparison of the go retention time with authentic samples . All samples were analyzed immediately after photolysis. Quantum Yield and Quenching Studies Quantum yields for product formation and Stern Volmer quenching constants were measured by the same methods as those for the pyridyl ketones and their hydrochloride salts . Alkeie formation was quenched by ethyl sorbate. Conversions were kept below 3% for quantum yield stuiies and below 5% for the tube without quencher in the quenching studies . The error estimated in the quantum yield studies was deter- mined by carrying out at least duplicate runs per cmplex and found to bets %. Duplicatequeichingrmsindicateai-8%errorinthequ determination. Table 13 lists the quantum yields obtained from the camplexes synthesized using granular zinc chloride for the zinc mercury amalgam. Table 14 lists the quantum yields and kq‘t values obtained from the complexes synthesized using powdered mercuric chloride for the zinc mercury amalgam. The Stern Volmer plots for the carpounds in Table 14 are presented in Figure 26. Intermolecular Photoreduction The irradiation procedures and methods of photOproduct identi- f icaticn were identical to those used in the intermolecular photore- duction studies of the pyridyl ketone hydrochloride salts . Irradiation of acetonitrile solutions of the acetylpyridine pentaammineruthenium (II) curplexes in the presence of p—xyleie , l-phenylethanol or 2-propanol 68 7.0 i 6.0 ~ 5.0 ‘ ”11,0 4.0 3.0 - 1 ‘ ' I 0.2 0.3 0.4 0.5 [Ethyl sorbate] . (M) Figure 26. Stern Volmer plots for mmevmo) , Ru4VP(.) , Ru3v1>([j) , RuBMeSBP(-) and RuBMe4BP(A) in acetonitrile. Formatim of alkene monitored. 69 Table 13. Quantum yields for [Ru (11143) 51.] [BF 412 in acetonitrilea 0 <1) _L_. _EEEPEEE. .03. .33. C) __N 0.0035(0.00804) 0(0) 0(0) ‘\ ./ c) " 0.081 (0.12) 0.01(o.04) 0.08(o.063) ‘\ ./ c) N 0.0097 0.0081 0 o o 0‘ W ( ) () () 6‘0.01 M, irradiated at 313 nm; synthesized from granular zinc chloride for the zinc mercury amalgam; recrystallized from water; nutbers in parenthesis refer to the quantum yield obtained in the presence of the sensitizer acetophenone. was accatpanied by decreases to various extents in the optical density of the MCI‘ band. Camplete bleaching of the MCI“ band resulted upon irradiaticn of the acetylpyridine pentaamminerutheliuMII) camplexes in the preselce of p-xylele for the time required for measureable l , 2-di-p—tolylethane formation . In quantum yield studies with 2—pro- panol, a blue shift and less dramatic decrease in the optical deisity of the MLCI' band acccmpanied acetone fonmaticn : [Ru4AP]o,M : 0.0108 0.00998 0.00961 0.00990 0.00990 [2-propanol] ,M: 1.005 0.804 0.603 0.403 0.201 A m, 11m : 503 500 500 500 500 [Ru4AP], M : 0.00951 0.00893 0.00817 0.00753 0.00604 70 Table 14. Phctckinetic data for [Ru(NH3)5L][BF4]2a in acetonitrile. b -1 ‘1’ prOpene 4’ AP ‘1’ L qu ' M I; /ji\\ 0.0 0.028 - - \( /' . .N... 0.020 0.0 0.043 22.0 <§L:2>/Ja\\/’l\\ V’JL\"/°\"/’ 0.020 0.0 0.081 10.5 N\ / \ / / 0.0 0.0 - - §<:::>/Ji\~/"\v” 0.019 0.0 0.0 6.6 C) C) 0.020 0.0 0.0 5.7 fig:j2>’JL\V//\\T// al0.01 M, irradiated at 313 nm; synthesized using powdered zinc chloride for the zinc mercury amalgam, recrystallized frum water. bAP = acetyl- 71 [RuBAP]O,M : 0.0100 0.0104 0.0104 0.00937 0.00949 [2-propanol] ,M:0.999 0.799 0.599 0.400 0.199 Amax' nm : 395 395 370 370 370 [R113AP], M : 0.00805 0.00793 0.00616 0.00495 0.00540 Formation of acetone was not detected in identical unirradiated -1 samples Plots of Qacetcne 27) and values for the lepe and intercept are listed in Table 15. versus [2—propanol]'-l are linear (Figure Irradiation of 0 . 01 M acetonitrile solutions of peltaamminepyridine- ruthenium(II) tetrafluoroborate and pe1taammine[l-(4—pyridyl)pelta- rxme]nrthemium(II) tetrafluoroborate with 1.0 M 2-pr0panol produced acetme with quantum yields of 0.059 and 0.115, respectively. Table 15 . Photokinetic data for the intermolecular photoreduction of the pyridyl ketone peltaamninerutheniumul) tetra- fluoroborate camplexes in acetonitrile . Lorelei __Dawr 5122s Intercept RuBAP 2-prcpanol 10 . 9 0 . 975 Ru4AP 2-propanol 5 . 75 2 . l a0.01 M complex, irradiated at 313 nm; all slopes and intercepts analyzed by least squares. Stern Volmer quenching studies were performed by the irradiation at 313 or 366 mof acetonitrile solutions 0.01 M in acetylpyridine pmtammmirerutrmim (II) and containing a constant amount of 2—propanol and varying amounts of quencher. Conversions were kept below 7% for thetubewitloutque‘ncl'erandnoquelchingvas observed forthefollowr ing series of quenchers: naphthalene , 2-chloralaphtha1ene , ' 72 60‘ 50‘ 40‘ 30‘ 20- 10 ‘ ' I T V I 140 2.0 3.0 4.0 5.0 [2-Propanol] -1 M-1 Figure 27 . Dependence of quantum yield of acetone formation on 2-propanol concentration in acetonitrile , Ru4AP (O) and mm: (0) . 73 1-naphthylacetic acid, 1,3-cyclcoctadiele, fumarcnitrile, 2,3—dimethy1— 2-bute1e and 2 ,4-hexadielol . The quenching observed with ethyl sorbate was nonlinear and nonreproduceable . Emission Studies No emission is observed for these complexes at room temperature and 77°K. Rhenium Complexes Preparation and Ideltification The BrRe(CO) 3L2 camplexes, where L is a pyridyl ketone, were synthesized by refluxing pemtacarbonylbrmorheniumu) with the appro- priate pyridyl ketcne in benzele ( 27) . The exact synthetic procedure is detailed in the Ebcperimental Section. The absorption spectral data 80°C belzele BrRe(C1C))5 + 2L 1, BrRe(CO)3L2 + 2CD (27) are listed in Table 16 , along with abbreviations for each complex. Represeltative absorption spectra are shown in Figures 28 and 29. A11 carplexes have high emergy absorption bands at 277 mm. The white oLtrLo- and yellow fi-substituted camplexes exhibit distinct low energyMLCI‘bands, whileashoulderat 300nmisobservedforthe red-orange Leta-substituted complexes. The infrared spectra of the pyridyl ketale rhenium(I) complexes exhibit four bands in the CO stretch region (Table 17) . The three high frequelcy bands are consis- tent with the facial arrangement of the three carbon monoxide ligands61 andthelcwest frequencybandresults frumtheCOstretchofthe carbonyl of the pyridyl ketcne ligand. A slight shift is observed for 74 Table 16. Absorption spectral data gor the bromotricar'bcnylrhenium (I) pyridyl ketone complexes . Camplex A max’ nm( e , M-lem—l) 6313”“,M-1am-1 13rRe(00)5 sh m 350 (180) 326 (545) 355 BrRe(CO)3(N\ />)2 sh m 300 (8620) 277 (10075) 6835, 1025‘D (RBPY) O A? BIRewOHWM 468(4165) 277 (13170) 6700 (ReZAP) o _N BrRe(CO) 31%” 465(3100) 277(9695) 4325 (ReZBP) 0 __N BrRe(CO)3(@/u\/\/)2 468 (2265) 277(8230) 3590 (ReZVP) N 0 BrRe(CO)3(<\—>/“\)2 sh m 300 (8290) 277 (10900) 8290 (Re3AP) 0 ()(‘N 1 sh 5(24) 221 BrRe 00 m 30 7 5 0 3 \ / 2 (Re3BP) 0 N- BrRe(CO)3(<\)/u\/\q 2sh m 300 (10050) 277 (13430) 10050, 2800b (Re3VP) BrRe(CD)3(N©/k)2 345(8230) 277 (9175) 5850 (Re4AP) magmg/sz .77.... (Re43P) O BrRe(CO)3(N@/u\/\/) 2 344 (10270)277 (10320) 720, 8140b (Re4VP) aBenzene solvent. bEbctinctim coefficielt at 366 nm. 75 0.9: 0.8- 0.7- 0.6v 0.2‘ 0.1‘ f 0 I 300 350 400 wavelength, nn) . . -5 . page 28. Absorption spectra of 7.7 x lo M BrRe(CO)3[1-(3—pyrldy1) peltanone] (--) and 2.52 x lO-4M 1-(3-pyridyl)pe1tanone(---) in.benzene. 76 0.9- 0.8' 0.7- 0.64 O 0 U1 I Optical density 1 l 0 | '1 02-) . 0 0 0 0 0 0 1 \ 0.1- 300 350 I 400 450 Waveimgth' nm Absorptim spectra of 1.01 x 10_4 pentanone] (___) am 2.54 x 10"4 (‘5’) in benzene. Table 17. 77 IR bands in the CO stretching region for the pyridyl keton- bratotricarbonylrhenium (I) carplexes . Catplex BrReWOO)5 RePY ReZAP ReZBP ReZVP Re3AP ReBBP Re3VP Re4AP Re4BP Re4VP 2050 2025 2027 2026 2030 2025 2022 2050 2039 2025 (D! -1 (IT! (a) 1990 1926 1933 1927 1926 1929 1925 1922 1930 1939 1923 1885 1908 1908 1888 1893 1894 1883 1890 1902 1886 1621(1698) 1615(1694) 1618(1691) 1693(1691) 1693(1687) 1698(1690) 1690(1697) 1695(1695) 1675(1701) aTimbers in parenthsis refer to the corresponding free pyridyl ketones in methylene chloride. bMethylene chloride. the meta and para complexes, while a larger shift (80 cm-l) to lower frequency is observed for the ortho complexes. Mass spectraldata show that the loss of carbon monoxide carpetes with the loss of pyridyl ketcne. Clerical ionization using methane as the carrier gas gave the pyridyl ketone ligand as the base peak. Electron impact gave ligand fragmentation of the meta and para cmplexes to the same base peakas thatobserved for the free pyridyl ketones. Them/e valte diserved for ReZVP suggests coordination of both nitrogen and oxygen in the ortho-substituted catplexes as described in the Discus- sion Section. Complex Stability The complexes were found to be stable in solution and not sensi- tive to air or daylight. When analyzed by vpc, the dissociaticn of the 78 pyridyl ketone from the rhenium(I) catplex is dependent on the terpe— rature of the injection port (Table 18) . The pyridyl ketones were identified by comparison of the go retention time with an authentic sample. The maximum ligand dissociation observed for each catplex is listed in Table 19 and quantitative dissociation is observed for only R34AP, Re3VP and Re4VP. Table 18 . Variation of pyridyl ketone ligand dissociation from the rhenium(I) calplexes with injection port temperature.a c_agplex Tetpgrature % Fragmentation ::jj>)’ji‘~ 145 19 i 2 BrRe(CO) ( ) 190 36 .t 4 3 N\ / 2 200 79 1:3 210 82 .+. 3 235 94 1 3 _ O BrRe(C0) (NW 140 41 i 4 3 \ / 2 180 53 i 2 195 91 i 3 208 100 i 2 223 96 1 3 230 97 r 2 aBenzene solution. Table 19. Maximum ligand dissociation of pyridyl ketane observed for BrRe (C0) 3L2 in benzene. g. Injection Port Temperature(°b) % Fragmentation ZAP 250 50 i 5 288 235 37 i 4 ZVP 250 66 i 2 3AP 250 66 i 4 3BP 235 43 t 2 3VP 230 99 i 2 4AP 235 97 i l 4BP 240 42 i 4 4VP 230 98 i 2 79 Photoproduct Identification and JQuantum Yield Studies All catplexes produced only the starting ketone upon irradiation at 313 nm, which was identified by canparison'of the vpc retention time with an authentic sample. Alkene and acetylpyridine were not detected. The quantum yield studies for protoproduct formation were carriedoutusingthesamemethodas thatusedforthepyridyl ketones. Benzene solutions containing 0 . 01 M branotricarbcnylrhenium (I) butyryl and valeryl pyridine carplexes were irradiat in parallel with 0.1 M solutions of valerophenane actinaneter in benzene . Only the original ligandwasdetectedaftertheirradiationat 313nm. Alkeneand acetylpyridine were not detected. A11 photoproducts were identified by carparison of the go retention time with an authentic sample. The results are shown in Table 20. While no Type II fragmentation was observed, sure of the pyridyl ketone ligand disappeared and a Color change occurred. The infrared spectra showed neither the appearance Table 20. Results for the quantum yield stuiies on BrRe (00) 31.2.a b b E t irr (hr .) Color change (DAP (1)-L 2vp 2.5 Red Deepred 0(0) 0.511(0.315) 24.0 Red Deeper red 0(0) 0.052(0.075) 3VP 2.0 Colorless Yellow 0(0) 0.140(0.181) 24.0 Colorless Yellow 0(0) 0.072(0.046) 4AP 8.0 Yellow Orange - 0.073 4VP . Yellow Orange 0(0) 0(0) 2 5 8 . 0 Yellow Orange-red 0 (0) 0 . 011 4 0 Yellow Red 0 (0) 0.029 (0.035) a"Benzene solvent, irradiation at 313 nm, [ReZVP] = 0.006 M, [Re3VP] = 0.0094 M, [Re4AP] = 0.011 M, [Re4VP] = 0.01 M. bNmbers in parenthesis refertothequantumyieldsobserved inthepresence of acetophenone. 80 of new peaks nor a change in the position or size of the bands in the carbonyl region. The concentration Change calculated f run the change in optical density of the low energy ML‘I‘ band or shoulder at 300 nm was less than that seen by vpc arnalysis. This data suggests that a change has occurred in the oxidation state of the rhenium metal ion as discussed later. Intersystem Crossing Yields The quantum yield of isarerization and the efficiency of inter- system crossing were detenmined using the same method as that for the free pyridyl ketones. The results of the irradiations with c_i_s—l,3- pentadiene at 313 nm and Eggs-stilbene at 366 nm are given in Table -1 versus qtencher cancentration is linear as 21. The plot of (40¢) illustrated for sane of the catplexes using gi_s-l , 3-pentadiene as a quencher in Figure 30. Mnent_ra_ns_-stilbene is used as a quencher, no changeswereobservedintheinfraredspectraandall stilbenewas accounted for after protolysis. Emission Spectra Corrected emission spectra (see Experimental Section) were obtained at room tenperature and at 77°n< in methyltetrahydrofuran (MeTHF) , a S : 1 mixture of methylcyclohexane : 2-methylbutane and a 5:5:2 mixture of ethyl ether:2-methylbutane:ethanol (EPA). Cancentra— tims of the pyridyl ketone rhenium(I) complexes were approximately 2.0 x 10-414. No emission was detected at room terperature and all emission bands at 77°K were broad and featureless. The same n‘ max emission band was observed in all cases, with or without the phosphoro- scope attachtent. The emission maxima of the pyridyl ketone bruno- tricarbonylrhenium(I) complexes are listed in Table 22. 81 Table 21. Sensitization of diene ismerization by BrRe (CO) 3L2 .a QA= _CE-l , 3-Pentadiene QB=tran trans-Stilbene b . b _L— [Q] I M (DC-rt [Q] I M «St-)0 "' pL_ 0.40 0.0245 0.008 0.00045 ig ,) °isc ’ °°°33 0.50 0.0234 0.01 0.00920 é 8= 0 17 0.66 0.0322 0.02 0.0158 isc ' 1.01 0.0294 0.04 0.0855 c) 4 0.040 0.0044 \ / 0.50 0.0061(0.502) ¢ A.= 0 22 0.68 0.0085(0.503) isc ° 1.01 0.0106(0.0516) 0 7' 0.40 0.34 0.0083 0.208 \ / 0.50 0.37(0.45) 0.0104 0.238 ¢ .A2 0 93 0.66 0.43 0.0207 0.286 isc ' 1.00 0.41(0.51) 0.414 0.396 4 0.98 0.40 0.68(0.36) 0.008 0.66 0.50 0.70(0.39) 0.01 0.56 0.66 0.80(0.42) 0.02 0.92 =2 5 1.00 1.01(0.45) 0.04 1.05 B: 2. 8 N.. Aph 0.40 0.40 0.008 0.33 \ [isc _ 2. 3 0.50 0.47 0.102 0.35 1.00 0.69 0.203 0.41 B_ 0 78 0.41 0.51 d>Ji.SC aBenzene' solvent, irradiation at 313 nm for c_i_s_-l ,3-pentadiene, irra- diation at 366 mm for trans-stilbene, [RBPY] = 0.00049 M, [ReZVP]= 0. 0028 M, [Re3VP]= 0. 0002 M, [Re4VP] = 0. 0004 M. thbers in parenthe— sisarethe<1>c_ytforthefreepyridylketornesinbenzene. 82 Fifle 30. The sensitized isarerization of gig-1,3-pentadiene by bfiw(0)' Re4VP(.) and Re3-benzoylpyridine(D) in zene. Representative emission spectra are shown in Figures 31 and 32. The emission W of the meta-pyridyl ketone brunotricarbonylrhenium (I) canplexes is essentially independent of the wavelength of excitation. The emissian )‘max of the Eng-pyridyl ketone brcmotricarbonylrhenium (I) complexes shifts to lower energy when the energy of excitation is increased. 83 Table 22. Emission maxima of the pyridyl ketone brcnotricarbonyl- rhenium(I) carplexes at 770K.a complex *exc' nm lean“ nnn Eh” kcal/mol Re3AP 267 488 58.6 303 478 - 59.8 Re4AP 277 542 52.7 367 500 57.2 Re3VP 267 477 60.0 303 477 60.0, 58.7,b 60.4C Re4VP 277 546 52.4, 53.5b 367 493 57.9 aEPA solvent unless otherwise noted. b5:l methylcyclohexanez2-methyl- butane. °MemHIu 84 gfifig3>fig “T1 wgamfigmqumxwogoxgwfig 3am C3 gmmm Mo 058mm c03mm3cm 05H. .VE. um ......Zam ado ridge E: . £553ng oom omv cow - L - (I I. ~. \wxn \ .. \\.\\. N..... \ . \... \ .. \ .6 \M. x I... \\..~. ) \ .. I o lo \ no I. . s .. ” I00 \ v0! . \ .. I I . \ N I 00’. \ coo ’ ... \ .. ’ o ‘ on I {If \ 0\ II a .. I I on. to / ...... ~ .... co \ I .. \ ’ .al \ ’I’ 00.00 \\ \I "illotooo \ ‘ H5 a ... x x at... \\ s '0.» Q . 1" ‘ 0900‘ \ \0. ol\ .- 2. ... . om mmmmmfim J sin-urn K191410112 ' Kirsuetnur uorssrue eAneIea 85 .MR um T11 «mm ocm TV mcmusflwfimcnmuocflnmngowoafig 32m :3 gvmm mo ofiommm :03nm3fiw mom. E: .fimcm3go3 oom omc oov omm b r _ . 3m wmmafim 81mm £19an 'Kntsuenm 110158919 GADPI‘aa DIRZUSSICN The goal of this work was to measure the rate of internal conver- sion between the IL excited state and the MILT excited states. The discussion is divided into three parts. The first section deals with the photochemistry of the ligand pyridyl ketones and the pyridyl ketorne hydrochloride salts which are used as models for the metal canplexed ketones . The second section deals with the preparation and characterization of the inorganic ccnplexes . The last section discusses the photochemistry of the pentaammineruthenium(II) and brato- tricarbonylrhenium(I) pyridyl ketone canplexes. Pyridjl Ketone Photochemistry Quantum Yields In benzene solutien, the fragmentation quantum yields for the pyridyl ketones are lower than those observed for the corresponding phenyl alkyl ketones (Table 23) and show more dependence on the aza 139 position than on the nature of the alkyl side chain. In polar solvents, the fragmentation quantum efficiencies increase, although the quantum yields are not unity in all cases, even when cyclobutanol 73 formaticxn is taken into account. The pyridyl ketone disappearance qnnntum yields in acetonitrile are also not unity (0.67-0.87) . 199 the relatively low In agreenent with previous observation , quantum yields of the pyridyl ketones are not due to quenching impuri- ties or to pyridyl ketcne self-quenching . The qtantum yields were 86 87 found to increase as the concentration of the pyridyl alkyl ketone was increased (Figure 7). A concentration effect of this type has been interpreted as solvatian of the biradical by ground state ketone . The quantum yield then increases in the same mamner as observed with added 71 These concentration effects also suggest that de- polar solvents . creases of the quantum yield in the _te_rt-butyl alcohol studies are not due to qLenching impurities , but to sate interaction of alcohol with the excited state. Protonation of the pyridine nitrogen results in drastic changes in photochemical behavior. Very low quantum efficiencies are observed even when acetonitrile is the irradiation solvent. The negligible change in quantum yield with increasing ketone concentration rules out self quenching. In the _te_£_t-butyl alcohol studies, the increase in quantum efficiency is minor, although the maximum quantum efficiency occurs at the same concentration as for the corresponding free pyridyl ketone. The similarity of quantum yields in acetonitrile and with added ;te_r_t.-butyl alcohol rules out any further quenching from solvent impurities . The best interpretation of the low quantum yields is that they are due to the presence of H+ and C1-. Lifetime measurerents, (vide infra), indicate that inefficiency does rot result from carpeti- tive triplet excited state reactions . Furthermore , material balances of 50% suggest that canpetitive biradical processes occur. Studies of the free pyridyl ketones in the presence of added salts. were limited by the solubility of such additives . Nonetheless , the decreased quantum yields are catparable to the fragtentation quantum yields of the pyridyl ketone hydrochloride salts . 88 Quenching Studies For carparison with the pyridyl ketones studied in this thesis , triplet lifetime data for the parent phenyl ketones are presented in Table 23. In art-butyl alcohol, the quantum yield of ketone dis— appearance for the phenyl alkyl ketones rises to unity so that l/ I Table 23. Photochemical data for the parent phenyl alkyl ketones in . a benzene solution. -1 -9 b 7 -l Ketone :12 kgr, M t, 10. s kr,10 s PhOOCHjCHjCH3 (BP) 0.35 670. 134. 0.75 pmocuzcnzcm (0113) 2 (BMeBP) 0. 36 245 . 49. 2 . 0 PhCOCH2CH2CH2CH3 (VP) 0.33 36. 7.2 14.0 PhDOCHZCHQCHZCH(CH3)2(yMéVP) 0.25 11. 2.2 45.0 aRef. 140. bkq = 5 x lo9 Mflcmfl in benzene, Ref. 69 and 141. equals the rate of gamma hydrogen abstraction (k1,).71 Although the quantum yields for the pyridyl ketones are not unity, the fact that the fragrentation yields are constant for the same aza sub- stituent allows for determination of kr in the same manner. The Norrish Type II fragmentation proceeds through the biradical inter- mediate in (32) and the fragmentation quantum yield is the product of probabilities in (36) . K0 —hL-+ 115‘ (28) * lkd 1K , K (29) O 89 ]_K* kisc 3 * , K (30) k * 3K (1 Ko (31) k * 3K —r——> Biradical (BR) (32) k BR —':-r——> K (33) k 0 BR —E—+ Fragmentation (34) ‘ k BR —‘-’1’9-> Cyclizaticn (35) _ _ k k <1’II ’ <1356113189}? ’ q’isc —r—— P (36) k +k k +k +k r d 9 eye -r Sensitization studies using the valerylpyridines indicate inter- system crossing to the triplet states (30) occurs with unit efficiency. Inefficiency must then result from triplet ketone decay (31) , ineffi- cient biradical fragmentation (33) or a canbination of (31) and (33) . In order for the quantum yield to remain constant for each aza substi- tuent while kr varies, the aza substittent mmlst affect only the proba- bility of product formation (tip) and not the probability of biradical 132 Thus kd less than unity result fmm inefficient fragmentation of the biradical. fonnation(¢BR) . << kr' 1/‘t equals kr and the quantum yields The photochemical kinetic data for the pyridyl ketones in benzene and acetonitrile are presented in Tables 24 and 25. The rate of hydrogen abstraction by the triplet carbonyl (kr) parallels the hydrogen bond strength in the order 3° > 2° > 1°. The ratio of reactivity for the 2° : 3° = l : 23 ortho pyridyl ketanes (1° 80) differs frem that ofthemeta(l°:2°=-rl 11)andpara(l° 2°:3°=1:11:46) pyridyl ketones. An unusually low value of r for ortro butyrylpyri- dine would nicely explain the discrepancy observed for the ortro isaners. The shorter lifetime results from the low quantum yields of 90 3Values of T are estimated on the basis that k.q equals 1 x 10 NFJSeC-l in acetonitrile. 71 Table 24. Photokinetic data for the pyridyl alkyl ketones in benzene. Ketone 4:1- I, 10'9 seca kr, 107 s-1 ZBP 0.16 107.5 0.93 2VP 0.20 4.65 21.5 yMeZVP 0.19 1.34 74.7 3BP 0.44 38.0 2.63 WBP 0.31 18.0 5.56 3VP 0.35 3.48 28.7 4BP 0.20 16.0 6.25 81484BP 0.16 - - 4VP 0.23 1.46 68.5 W4VP 0.18 0.35 289. aValues of T are estimated on the basis that k equals 5 x 109 M'lsec‘1 in benzene.69'l41 ‘1 Table 25 . Photokinetic data for the pyridyl alkyl ketones in acetonitrile. Ketone 311. n, 10.9 seca kr' 107 s-1 ZBP 0.25 58.1 1.72 M 0.70 5.59 17.9 WZVP 0.73 1.34 74.7 BBP 0.70 54.1 1.86 WBP 0.76 10.8 9.3 3VP 0.84 3.1 32.3 4BP 0.63 20.4 4.90 W 0.60 4.11 24.3 4VP 0.60 1.00 100. W 0.58 0.25 400. 10 91 2-acetylpyridine . This suggests that catpetitive reactions from the triplet excited state are occurring as previously observed for 2-butyrylpyrimidine . 129 ’ 130 The triplet lifetimes of the pyridyl ketone hydrochloride salts are much shorter than those of the corresponding free pyridyl ketones . Equating l/Ttokr forthemeta (1° : 2°=1 : 8) andpara (1° : 2° : 30 = l : 8 : 12) carpounds indicated a decrease in hydrogen atam selectivity (Table 27) . To determine whether 1/ T contains an appreciable k d' k d was independently measured. The photokinetic data for the bimolecular photoreduction of the meta and para acetylpyridine hydrochloride salts are presented in Table 26. Table 26 . Kinetic data for the intermolecular photoreduction of 3- arnd 4-acetylpyridine hydrochloride in acetonitrile . Ketone Donor kr, M-lsec-1 k d' sec-l 0m a 3APHCl 2-Propanol 2.8 x 107 1.5 x 108 0.55 41mm 2—Propanol 2.8 x 108 1.9 x 108 0.86 41mm l-Phenylethanol 2.8 x 108 9.0 x 108 - a[antum yield of acetone fomation . The initial photochemical steps , including intersystem crossing and the mechanism of hydrogen abstraction by the reactive triplet ketane excited state, are the same as in intramolecular photo- reduction . The maximum quantum yields of acetone fonration indicate that hydrogen abstraction is an efficient reaction. The efficiency of intersystem crossing mmnst be at least 60% and 90% respectively, 92 for the meta arnd para canpounds. The rate constants of triplet reactions , We}? , are much higher than those observed for the _;tcrt_-butoxy radical (kr = 1.86 x 106 M-lseC-l) ,142 acetOphenone (kr = 6 Mmlsecul)90 and benZOphenone (kr = 1.3 x 106 Mulsecd)9O 1 . 8 x 10 when 2-propanol is the hydrogen donor . These results suggest that the first step is not direct hydrogen abstraction . The mechanism may be similar to that observed for trifluoroacetophenone which 115 Further experimental involves charge trans fer interactions . evidence for the occurrence of Charge transfer upon irradiation of the pyridyl ketone hydrochloride salts is the fact that the Type II fragmentation of 4VP is not quenched by p—xylene whereas that of 9 1sec-1. Since the triplet 4VPIC1 is quernched at a rate of 5 x 10 M- energy of p—xylene (80 kcal/mol) lies well above the triplet energy of 4VPI-Cl (ET = 70.9 kcal/mol) , exothermic energy transfer cannot occur and quenching must result frem charge transfer. Under these eperi— mental cornditions , the rate of p—xylene charge transfer quenching is faster than naphthalene quenching of the triplet ketone. The lack of quenching of 4VP must be interpreted as the absence of Charge transfer interactions with free ketone . The higher ionization potential of ben- zene (IP = 9.25 ev)144 makes it less reactive than p—xylene (IP = 8.44 144 and, as expected, 1'14 quenching of 4VPHZl is not observed. ev) . Regardless of the exact nature of the bimolecular reduction mechanism, the kinetic analysis allows for an unbiased determination . of kd. The high values of kd and the observation of two different values of k d for 4API-I:l were quite unexpected. Possible causes are ground state processes influencing the quantum yields. However, the 93 enhanced decay could also be rationalized from Charge transfer inter- actions. The high kd for 4APHC1 with l-phenylethanol, 9.0 x 108 M-1 sec"l , is inconsistent with product quantum yields in the corresponding intramolecular plnotoreactions. Specifically, this would not allow for 8 -l . . . s . The ionization product formation with 4BP where 1/T = 4.3 x 10 potential of 2-propanol (IP = 10.15 ev) 144 would not allow for charge transfer interaction. Using the experimentally determined values of kd pyridyl ketone hydrochloride salts were determined and are presented from 2-propanol, the rates of gamma hydrogen abstraction for the in Table 27. The rate of gamma hydrogen abstraction also parallels the strength of the gamma.hydrogen bond (3° >2° >1°). The high percentage of decay predicted for the meta (73%) and para (42%) butyrylpyridine hydrochlorides contradicts the observed minimal changes in quantum yield . This suggests that k d determined from the 2—propanol studies is unaccountably high and most likely represents Table 27 . Photokinetic data for the pyridyl ketone hydrochloride salts in acetonitrile. 8 -l 8 -l a 8 -l Ketone (DII 1/‘1’, 10 s kr, 10 s kd, 10 s BBPKZl 0.23 2.4 0.9 1.5 BMeBBPKZl 0.19 7.6 6.1 1.5 3VPI-Bl 0.27 20.4 18.9 1.5 4BPH21 0.092 4.3 2.5 1.8 W1 0.16 13.5 11.7 1.8 4VPI~I21 0.12 33.0 21.2 1.8 yMe4VPHCl 0.13 50.0 48.0 1.8 aValues of ‘r are estimated on the basis that kq equals 1 x 1010 M-1 3.1 in acetcxnitrile.71 bkr = (1)-1 - kd. 94 a maximum value for decay. The gamma hydrogen selectivity for the pyridyl ketone hydro- chloride salts (1° : 2° : 3° = l : 9 : 20) differs from the selecti- vity of the pyridyl alkyl ketones (1° : 2° : 3° = 1 : 11 : 46) and phenyl alkyl ketones (1° : 2° : 3° = 1 : 12 : 55). This decrease in selectivity may be related to similar observations for cation radicals. The hydrogen atcm transfers observed for the molecular cation radicals of ketones (McLafferty rearrangement) 145 are 101an to be similar to the gamma hydrogen abstractions observed for triplet 146 ketones . These reactions involving the breaking of carbon-hydrogen bends occur with the expected wide range of deuterium isotope effects. Deuterium isotope effects are not found in the mass spectroscopy study of 2-hexanme—5-d .147 148 also observed the lack l of deuterium isotope effects in the Hoffman-Ioeffler—Freytag rearrange- Green andcoworkers ment of deuterated N-chloro-Z-hexylamine. The electron deficient character of both sources of reactivity for the radical cation was hypotresizedtoleadtoabstractionofthecarbonboundhydrogenwith lower energy of activation carpared to neutral molecules . By analogy , the electron deficient triplet carbonyl excited states of the pyridyl ketone hydrochloride salts abstract the gamma hydrogens with a lower energy of activation than the free pyridyl ketones, resulting in decreased selectivity . Reactivity and Eff iciengy Enhanced reactivity of the pyridyl ketones is expected since the nitrogen atcm of the pyridine ring is an electron withdrawing substi- * tuent149 and activates the electron deficient n,m triplet excited 95 state towards gamma hydrogen abstraction (37) Protonation of the 3 )- \/ nitrogen renders it more electron deficient and the triplet carbonyl 119 suggests that is further activated. Previous spectroscopic work the n, 11* triplet excited states for the pyridyl ketones lie lower (para < ortho < meta '5 phenyl) and the m,m* triplet excited states of the pyridyl ketones lie higher (para > ortho > meta > phenyl) rela- tive to those of the phenyl alkyl ketones in nonpolar solvents. Since the n, 11* triplet states are of lowest energy, the exact energy of the 11,111.: triplet excited states cannot be measured. The same order of reactivity is observed in both benzene and actonitrile solutions , kr(para) > kr (meta) > kr(ortho) . The underlying reason for this observed order is not Clear. Decreased mixing of the triplet states predicts kr(para) > kr(ortho) > kr(meta); while indnotion, where nitrogen acts as an electron withdrawing group, predicts kr(ortho) > kr(meta) > kr (para) . The rate data indicate that induction plays a minor role in influencing the rate of gamma hydrogen abstraction since the aza substituent has the greatest effect an enhancing triplet reac- tivity when it is farthest away. Low quantum efficiencies may be attributed to a oarbination of low efficiencies of intersystem crossing, biradical fonration and biradical fragmentation. The high rates of biradical formation (kr) versus decay (Rd) rule out inefficient biradical fomation. The unit efficiency of intersystem crossing observed for-"the pyridyl ketones 96 leaves only an inefficient biradical fragmentation as the cause of the low quantum yields. Delocalization of the carbon radical electron into the pyridine ring ((38)-(40)) is consistent with the fact that nitrogen is an electron withdrawing group and alkyl radicals are electron 150 donating groups. Only in the case of meta substitution, can the carbon radical electron not be delocalized onto the nitrogen. The meta aza substituent has no effect on the stability of the biradical and the quantum efficiency is similar to that observed for the parent phenyl alkyl ketanes . For ortho and para substitution , electron delocaliza- tion creates the charge separation illustrated in (38) and (40). The partial positive charge on oxygen is best relieved by reverse gamma hydrogen transfer and the quantum yield is decreased in camparison to the phenyl alkyl ketones. If intersystem crossing occurs with comparable efficiency in the pyridyl ketone hydrochloride salts , inefficient biradical fragmen- tation is again responsible for the low quantum yields . The actual reason for the extensive decrease is mkmwn. Hmever, very fast 11 (.m— L: k-O‘ In IW1 '71 'ri 97 reverse gamma hydrogen transfer is possible. Furthermore, the low mass balances suggest competitive biradical reactions may also occur . §ynthesis and Progties of the Inorganic Complexes The background on the excited state behavior of the ruthenium and rhenium complexes in the Introduction illustrates the wide range of ' photochemical behavior normally observed for organa'tetal lic complexes . The energy levels which affect the photochemical behavior are derived fram molecular strnrstmre65 and an examination of the physical proper- ties is necessary to interpret the results of the photochemical H studies. Hridyl Ketone Pentaammineruthenium (II) Carplexes The synthesis and purification of the pentaammineruthenium(II) pyridyl ketone complexes proved somewhat difficult, as has been experi- lSl , 152 , 153 enced by other workers. The spontaneous color changes often observed, e.g. in the synthesis of chloropentaamminerutheniuMII) di- 154 chloride, were first observed in 1804 for acidic ruthenium metal 155 The rednxztion of ccmplex solutions and are unexplained to date. chloropentaaxmninerutheniuMIII) camplex under the same experimental conditions , but using different formns of mercuric chloride for the zinc-mercury amalgam, gave complexes with comparable absorption spectra but different elenental analyses and different photochemistry. The characteristic features of the absorption spectra of the pyridyl ketone pentaammineruthenium(II) camplexes are the IL bands in the ultra-violet region and intense MLCI‘ bands156 in the visible region. The «,1? pyridyl ketone transition is shifted to higher energy upon coordination of nitrogen (Am (1213*)... AWGCZL ’salt) < nmxfiree * ketone“ . Coordination also removes the n,1r transition associated 98 with the ring nitrogen and thus produces a sharper m,m* band. The enhancement of absorption in the carbonyl n,m* transition region (313 nm) is most likely due to underlying metal d-d transitions as observed in the corresponding pyridine complex. The position of the MLCI‘ band for the camplexes is dependent on the position of the acyl group relative to the pyridine nitrogen and independent of the nature of the alkyl side chain (Table 9). It is interesting that meta acyl substitution on the pyridine ring produces little change in the energy of the MLCI' bnad. The occurrence of low energy barnds in the ortho complexes might irndicate coordination of both pyridine nitrogen and carbonyl oxygen to the ruthenium(II) 157 , 158 metal center. To minimize dipole moment, the pyridine nitrogen 159 and carbonyl oxygen are usually trans, but in the presence of metal 60 ions, the cis conformation is often preferred (41) .1 Bidentate / I (41) \ R (..o “M K o l ligrnad behavior is normally accarpanied by a 40-60 cm- red shift in the inf i i Y1 fr 361,162,163 however the ortho complexes do not show an appreciable shift frum the meta and para pyridyl ketone pentaamminerutheniumul) canplexes. No infrared data are reported for the ortho coordinated ruthenium(II) complexes in the literature157 so the exact nature of bonding in the ortho pyridyl ketone ruthenium (II) complexes is uncertain. 99 The pyridyl ketone pentaamminerytheniumUI) complexes have a propensity towards decomposition in solution, most likely through oxidation.45 or ligand substitution. They are unexpectedly stable toward gc fragmentation, even though other ruthenium(II) conplexes are known to fragment quantitatively at temperatures greater than 200°C.164 Whitten51'52 displaced 4—stilbazole from [Ru(bipy)2(4- stilbazole) 2] 2+ using triphenylplnosphine and Dwyer165 displaced pyridine from g_i_§--[Ru(phen)2(py)2]2+ with chloride ion. The applies}- . tion of these methods and others did not result in quantitative displacenent of the pyridyl ketone ligand from the pentaammineruthe— nium(II) complex. It is krnown that when not influenced by the "trans" effect, ligand which are good donors (e.g. NH3, pyridines, N2) are not very labile in solution,45 presumably due to m-back bonding from the metal center.165'l66'167 Since the pyridyl ketone infrared carbonyl stretch frequencies are shifted to lower energy in the com- plexes, ruthenium(II) back bonding may be a possible reason for the lack of fragmentation. The meta and para pyridyl ektone pentaamminerutheniuMII) com- plexes were used for photochemical studies . The complexes are in the +2 oxidation state, since the corresponding ruthenium(III) complexes lnave no MLCI' barnfi.42'169 The complexes contain only one pyridyl ketone ligand. A dipyridyl tetraammineruthenium (II) complex would have a MICI‘ A max twice as large as that observed. The correct carbon analysis verifies that only one pyridyl ketone is present. The low nitrogen arnd hydrogen analysis suggest that one of the amine groups in the complex has been replaced by water or chloride ion. Any trace amounts of hydroxy or chloro tetra-mmineruthenium(II) complex would 100 betoosmalltobedetectedandunabletobedistinguishedbyspec- troscOpic analysis since the absorption characteristics would be similar to the pentaammineruthenium(II) complex.42’l70 Byridyl Ketone Bronotricarbonylrhenium (I) Complexes In contrast to the pyridyl ketone pentaamininerutheniumfll) com- plexes , the solubility properties of tre pyridyl ketone bromotricar- bonylrhenium (I) completes allow for easy isolation and purification . The infrared of each complex exhibits a band for the carbonyl stretch of tie pyridyl ketone and the metal-carbonyl three band patternn asso— ciated with the facial arrangenent of the carbon monoxide ligands.61 Pyridyl ketone bronotricarbonylrhenium (I) complex formation occurs through the stepwise "trans-effect" mechanism (42) As a result, the Br Br Br 0:: ..oo 0c .00 oc, l . py-x ”@Re" m-x firms" py-x 4», Re» ( 4 2) oc’ ‘00 Cd \ py-x oc/ I pr-x co co co pyridyl ketone groups lie cis to each other . Attempts to substitute further CO groups in other systems have been unsuccessful.55 The nain bands in the absorption spectrum are associated with the high energy IL transitions and the rhenium to pyridyl ketone MLCI‘ transition.61 The IL band of the pyridyl ketone rhenium(I) complex occurs at approximately the same energy as that of the free pyridyl 61 ketone. As with other fag-me (CO) 3L2 complexes , the extinction coefficient of the band is at least twice the magnitude of the freepyridyl ketone. T‘hepositionofthelowerenergymcrbandis dependent upon the position of the carbonyl group relative to the 101 pyridine nitrogen and independent of the nature of the alkyl side chain - Meta acyl substitution on the acyl pyridine ring produces very little change in the MEET bnad energy . While all the bronnotricarbonylrheniuMI) complexes with the aza substituent in the same ring position lnave the same MLCI‘ )‘max' .the extinction coefficients at the )‘max arnd at 313 mm vary significantly. Sore completes , particularily the butyrylpyridine complexes , may lnave occluded solvent upon recrystallization. Although the complexes also display temperature dependent pyridyl ketone ligand dissociation and do not undergo quantitative ligand dissociation upon gc analysis, the probability of only one pyridyl ketone coordinated to the rhenium(I) metal center is unlikely. The infrared carbonyl stretch frequencies 1 the only monosubstituted rhenium(I) metal carbonyl 17 of Ph3PRe (CO) 3Br , complex in the literature, do not correspond to those of the synthe- sized pyridyl ketone bromotricarbonylrheniun (I) complexes in Table 17. Furthermore, the same carbonyl stretch and relative band inten- sities are observed for all the connplexes.59’60’61 The ortho pyridyl ketone rhenium(I) complexes are peculiar. The mass spectral fragmenta- tion pattern is suggestive of an ortho coordinated rhenium(I) species, however, the IR spectra are slightly different from those reported for other ortho-metallated complexes. 172 The low frequency infrared stretch observed for the ortho pyridyl ketone rhenium(I) complexes has no literature precedence. Photochemistry of the Organonetallic Cogplexes pyridyl Ketone Pentaamminerutheninm (II) ICotplexes The physical prOperties of the pyridyl ketone pentaamminerutheniun (II) complexes placed a limitation on the scope of the photochemical 102 studies. The spectral characteristics of sone of the pyridyl ketone pentaammineruthenium(II) complexes, even though in agreetent with the literature values (i.e. Rupy,156 Ru4AP50) were found not to be a good measure of complex purity166 and only those complexes with satisfactory elenental analyses were used for the photokinetic studies . The unknown nature of the pyridyl ketone bonding, in addition to the unsatisfactory' elerental analysis for the ortho pyridyl ketone pentaammineruthenium (II) complexes, are the basis for their elimination from the photochemical’ Type II fragmentation studies. The nordissociation of the pyridyl ketone ligard from the pyridyl ketone pentaammineruthenium(II) complexes oder vpc analysis corditions also limited the study to pyridyl ketone ligands whose alkene fragmentation products could be measured accurate- ly. Propylene and i__sg—butylene analyses were accurate to 3% . Niall/Sis for ethylene was nonreproduceable and eliminated the butyryl- pyridyl ketores as ligands for photochemical stLdies. The nondissocia- tion of the pyridyl ketone ligands from the pyridyl ketone pentaammi- nerutheniuMII) complexes under vpc analysis conditions did however allow for the direct measurenent of the photodissociated pyridyl ketone ligand. The use of spectroscopic analysis by ‘n:"ord41’43'49 to monitor photosnbstitution of the py-X ligands is complicated by the effects on the MLCT km optical density of additional decay path- ways. Gc analysis of alkene and pyridyl ketone are absolute measures of the upper ard lower excited state reactions . With spectrosc0pic analysis , the accuracy of the photosubstitution quantum yield restsontheassunptionthatthedecreaseinopticaldensityofthe MLCT A max rises solely from pyridine aquation. While c_i_s_- and 103 trans-[Rnn(m~13)4(py)(H20)]2+ (Am = 407 nm; Em(trans) 7700, Emcr lull-l)42 and [Ru(NH3)5py]2+ (n = 407 nm, e 7762 M’1 (cis) 6400 M max 156 om-l) have similar spectral characteristics, oxidation of ruthe— nium(II) to ruthenium(III) as [Ru(NI-13)5py]3+ (Am = 262 nm, e 4539 Ion-l)156 causes a decrease in the MICI‘ A max Optical density without M- the aquation of pyridine . The quantitative evaluation of any ruthe- nium(III) complex footed is complicated by the fact that all the reactants ard products have sore absorbance at these wavelengths and 41'” failed to give quantitative or ion exchange elution analysis qualitative agreement with the spectroscopic analysis . The quantum yield of alkene fonnation thus represents Type II fragmentation while quantum yields of pyridyl ketone formation repre- sent ptotodissociation (Table 14) . Acetylpyridine formation was not observed upon irradiation for any of the butyrylpyridine and valeryl- pyridine complexes , so none of the pyridyl ketone formed by photodis- sociation undergoes Type II fragmentation. The meta pyridyl ketone complexes which exhibit high energy MLCT bands at 412 nm are photo- labile, while the para pyridyl ketone complexes with lower energy bands at 503 on do not photodissociate in acetonitrile solution. This is consistent with Ford's model of photolabilization occurring only when the Am of the MLCT absorption band is less than 460 nm.49 Ford also found that a linear relation exists between the 49 py-X° zation for Ru4AP in acetonitrile; extrapolation of his data predicts wavelength of irradiation and log He observed photolabili— ¢4AP 0f 0.83 upon irradiation at 313 nm! While bleaching of the MLCI‘ band is observed upon irradiation of the para pyridyl ketone 104 complexes at 313 nm (Figure 25) , no free para pyridyl ketone is detected upon gc analysis. The decrease in MLCI‘ A max mnust then be the result of another reaction such as oxidation of ruthenium(II) to ruthenium(III) . The pentaammineruthenium(II) valerylpyridyl ketone complexes exhibited protochemical behavior which was dependent upon the type of mercuric chloride used for the synthesis of the reductive zinc mercury amalgam. Initial photochemical studies were carried out on the complexes synthesized using granular mercuric chloride. The photochemical results shown in Table 13 differ from those shown in Table 14 where the complexes were synthesized using powdered mercuric chloride. While the elerental analyses of the former complexes were poor, the spectral properties matched those of the literature and free valerylpyridyl ketone was not detected by 'gc analysis prior to plnotolysis. Further work on the clnaracterization of the pentaammnine- ruthenium(II) complexes indicated that only those complexes synthe— sized with the powdered mercuric chloride gave suitable analysis; further photochemical study was restricted to those. Coordination of the pyridine nitrogen to the ruthenium(II) metal center results in drastic changes in the photochemical behavior of the pyridyl ketone. The Type II fragmentation efficiencies are very low («2%) when compared to the corresponding hydrochloride salts (lo-15%) or free pyridyl ketones (70-908) . This results primarily from the different absorption characteristics of the metal complexed ketone and the corresponding free pyridyl ketone and hydro- chloride salt. Bonding to the ruthenium(II) metal center and for- mation of the hydrochloride salt both involve coordination of the lone 105 electron pair on nitrogen. If hydrochloride salt formation has the same effect as metal coordination in the absence of orbital mixing, multiplying the 4’11 of the ruthenium(II) complex by the ratio of the extinction coefficient of the complex to its corresponding hydrochloride salt corrects for total light absorption by the pyridyl ketone choro- phore. Taking into account the experimental error resulting from the variance in complex extinction coefficient, the corrected Type II fragmentation quantum yields of the ruthenium (II) complexes are com- parable to the quantum yields of the pyridyl ketone hydrochloride salts (Table 28) . Table 28 . Type II fragmentation quantum yields for the hydrochloride salts and pentaamnmineruthenium(II) complexes of the pyridyl ketones in acetonitrile solution. Hydrochloride Salts Ruthenium (II) Complexes . a c Pyridyl Ketone en Rb d’actual ¢corr l i BMeBBP 0.13 5.7 0.020 0.120 3VP 0.14 7.6 0.0195 0.150 W 0.13 4.4 0.0228 0.099 4VP 0.085 5.0 0.0185 0.093 yMe4VP 0.13 5.7 0.0228 0.096 aQuantum yield of acetylpyridine extrapolated to zero ketone concentra- . b _ 2+ C _. tion. R - (e313 um(Ru coupled)“ €313 mam salt). 400 - ”original, (R) ' The lifetimes of the ligand derived triplet excited states of the pentaanmmineruthenium(II) pyridyl ketone complexes are longer than the lifetimes of the corresponding pyridyl ketone hydrochloride salts . Eqnating 1/1 to kr for an initial evaluation of the triplet carbonyl 106 reactivityforthenetnuO : 2°=1 : 2) andpara (1° :20; 3°= l : 1.9 : 2.3) pyridyl ketone complexes indicated a dramatic decrease in ganma hydrogen selectivity (Table 29) . In the pyridyl ketone penta- ammninernntheniunMII) complexes, decay to the lower energy metal-ligand excited states can compete with tie intrinnsic decay of the ligand derived triplet excited state . Kinetically , these two rates of decay cannot be separately determined. Their sum however may be determined from the bimolecular photoreduction of the corresponding pentaammnine- ruthenium (II) acetylpyridine complexes . Table 29. Photokinetic data for [mn(1\II-I3)5L] [BF‘4]2 in acetonitrile. .5. 9:2“ 1/1, 108 .. sec"1 SWEEP 0.120 4.5 3VP 0.150 9.5 MP 0.099 7.7 4VP 0.088 15.0 MVP 0.096 17.5 aValues of n are estimated on the basis that kq equals 1 x 1010 M—1 sec-1 in acetontrile . Irradiation of acetylpyridine pentaanmmineruthenium (II) complexes in the presence of various hydrogen doors was complicated by competing conplex deconposition . Intermolecular photoreduction processes are normally slower than intramolecular pkotoreductions and strongly dependent upon the reactivity of the hydrogen donating sub- 5 1 1 155 with toluene, 7.0 x 1 1 strate, i.e. acetOphenone (1.2 x 10 M— sec- 5 1 1 114 and 1.8 x 106 M‘ sec' with 2-propa- m190) versus valerophenone (1.4 x 108 sec-1) .173 Irradiation of RuBAP 10 M. sec- with p—xylene , 107 or Ru4AP with the less reactive hydrogen donors toluene and p—xylene resulted in complete bleaching of the MLCI‘ )‘max without formation of any bibenzyl product. Irradiation of Ru3AP or Ru4AP with 2—propanol produced acetone and was accompannied by only 10-2 0% complex decomposi— tion. Honever , the production of acetone could not be quenched by any triplet quencher used. This lack of quennching was quite unexpected. Additional experiments indicated that the fornmation of acetone could also be the result of other carpeting reactions . Irradiation of an acetonitrile solution of pentaanmminepyridineruthenium (II) tetraf lLoro— borate with 2—propanol produced acetone , indicating that the presence of a carbonyl grow on the pyridine ring is not required for the oxidation of 2—propanol . Under identical conditions , equivalent amounts of acetone were produced upon irradiation of Ru4AP , Ru4VP or pyridine complex in acetonitrile. The existence of competing side reactions in this inorganic systeu is likely in light of the redox behavior observed with other 2+ 3] ruthenium(II) complexes. While [Ru (bipy) stoichionetrically reduces water to hydrogen, the analogous reaction with [Ru(trpy) 2]2+, [Ru(phen)3]2+ and [Ru(noipy)2(py)2]2+ shows ligand reduction, solvent reduction and loss of ligand competing with hydrogen production.174 Catalytic quantities of ((trpy) (bipy) R113] 2+ have been found to quan- titatively oxidize 2-propanol to acetone.175 In the absence of external hydrogen acceptors , ruthenium (II) complexes have been found to cause the dehydration of alcohols.176 The pentaammnineruthenium(II) system has not been studied as extensively as the polypyridyl ruthenium (II) systems. The loss of ligands indicated by the decrease in the mxmax optical density (43b) and the shift of the MICT xmax (43c) 108 suggests that a similar mechanism for dehydrogenation176 is occurring won irradiation with 2—propanol (44) . OH OH CH333‘3’13 I -" - r————-—; (NHB)5RU \ / ('DH (43a) +CH3. 3 o (NH3) SRuIIN h" e @113) SRuII] 2+ \ / 313 nm 0 (43b) N \ / o I _ L———~+ (NH3)4Ru IN\ / (43c) + NH3 NH3 or py-X NH:3 or py—X NH3 or py-X o HN NH HN NH HN NH 3 \\\ 3 _ + 3 e 3 _ 3‘ 3 3 NH4 a? oi3hcni3 % j ‘ / \ > ’Ru\ (44) H3N NH3 0 H NH3 H’ NH3 + CH3 CH3 H H CH3 CH3 In terms of pentaammineruthenium (II) pyridyl ketone photoreacti- vity, the observation of Type II fragmentation is positive proof that reaction from the ligand triplet excited state (kr) is able to compete with decay (3WD to the lover energy excited states and the ground 109 state (k d + kic) . The lack of quenching of acetone formation and its probable fornmation by other pathways indicates that the bimolecular protoreduction experiments cannot be used to quantitatively determine the rate of ligand triplet excited state decay. The rate of internal conversion can then be calculated by comparing the photoelimination data for the pyridyl ketone pentaanmmineruthenium (II) complexes and the corresponding hydrochloride salts as follows . Coordination to the ruthenium(II) metal center can be viewed as introducing two unknoms into the triplet state lifetime: an inductive effect on the rate constant for gamma hydrogen abstraction, kr; and competitive decay to the lower energy metal-ligand excited states with rate constant kic' In equation (45) , k: is the known triplet rate constant for gamma hydrogen abstraction by the corresponding pyridyl ketone hydrochloride salt. The unknown rate factor on game hydrogen abstraction introduced _. _ O — kr + kic — a(kr) + kic (45) by ruthenium(II) metal coordination is a. Substitutinng the values for 1/1 (Table 29) and k: (Table 27) into (45) and solving the pair of simultaneous equations for the meta coordinated pyridyl ketones gives a = 0.39 and Rio = 2.1 x 108 sec-.1. The three simultaneous equations for the para coordinnated pyridyl ketones do not give a real solution , 8 sec'l. This is best rationalized as a = 0.37 and Rio = +1.1 x 10 resulting from the compression of the pyridyl ketone ruthenium (II) complex lifetime ratios (l/n(RueMe4BP) : l/n(Ru4VP) : l/n(RuyMe4VP) = 1:2 2). Comparison of the kic value for the meta pyridyl ketonne penta- anmminerutheniuMII) conplexes with the observed quantum yields 110 indicates that this value of kic overestinmates the actual rate of decay. Calculation of k1. from k: for the meta complexes gives kr (RuBMe3BP) = 2.48 x 108 sec.1 and kr(Ru3VP) = 7.4 x 108 sec-1. Substitution into (12) gives the following expressions for the Type II quantum yields: ¢II = 0.53qnisccbP (RuBMe3BP) (46) (D11 = 0.784aisccpP (Ru3VP) (47) For meta substitution, $150 and ¢P are constant. Since the ch11 are constant (d>(RuBMe3BP) = 0.20, (Ru3VP) = 0.195). kic < kr' To account for the constant quantum yields observed for the para pyridyl ketone complexes, the ¢BR must also be constant with kic < kr. Thus, kr = l/n; and kic for both the meta and para pyridyl ketone complexes must be less than 108 sec-l. An excited state manifold incorporating kic is illustrated in Figure 33 . The retention of orbital parentage in radiationless tran- sitions184 and enhanced intersystem crossing from the heavy atom induced spin orbit cowlingz-l'184 in organonetallic complexes has been interpreted to indicate that kisc >> kic' Intersystem crossing in the pyridyl ketone rutleniuMII) complexes must be at least as efficient as in the corresponding hydrochloride salts Misc (meta) = 0.90, ¢isc‘(para) = 0.60) since the d> values are sinmilar. Reaction from the ligand excited state is then dependent won the rate of reaction of the ligand derived excited state (kr) relative to the rates of internal conversion to the lower energy metal-ligand excited states (kic) , decay to the ground state (k d) and emission (ken) . Pyridyl ketone “photoreduction is a known triplet state reaction. 67 111 JHI Products '1‘ Energy ——*| Fifi 33 . Jablonski diagram for a pyridyl ketone organnonetallic complex. The value determined above for kic as < 108 sec-1 must measure triplet state conversion. Relatively little data exists on the rates of TH + T1 internnal conversion. For example, Gillispie and Linm199 as well as 200 1 Liu & workers measured a kic of 1 x 1010 sec- for T + T internnal 2 1 conversion of 9,10-dibronoanthracene. The rate of internal conversion in the organonetallic system thus differs by a factor of at least 102. This difference may be attributed to the conbined effects of energy level separation and orbital overlap. Liu201 has indicated that the T2+ Tl energy gap for 9,10-dibronoanthracene and antlnracene slould be similar (31.9 kcal/mol) . The eergy level differences in the penta- ammnineruthenium(II) pyridyl ketone system may not be quantitatively detenmined because these conplexes do not emit. The pyridyl ketone 112 ligand triplet state is expected to lie at approximately the same energy as the pyridyl ketone hydrochloride salt ( rv70 kcal/mol) . The MLCI' energy may be estimated as below the Amax absorption bands (EMCI‘ (para) 4: 56 kcal/mol, EMLCI'(mta) m 69 kcal/mol) . The expected snmaller separation of energy levels in the organonetallic system does not lead to an enhanced rate. In the organonetallic system, the p-m orbitals of the pyridyl ketone overlap with the d22 orbitals of the ruthenium(II) metal ion. Although the carbonyl and ruthenium(II) metal center are not very far apart, the coplanar n and dxz orbitals are highly directed and almost perpendicular to each other. Therefore it is both the poor orientation of the orbitals and intervening pyridine nuclei which give poor orbital overlap resulting in a slower rate of! internal conversion . In the corresponding system [Ru(bipy) 2 (4-stilbazole) 2] 2+, Whitten suggested a kic value of 5 x 1012 sec-l.52 This rate is also much faster than the kic value determined for the pentaammineruthe— z» nium(II) pyridyl ketone corplexes. This discrepancy raises the ques- tion as to whether kiC in an organonetallic system is dependent only won the metal center or whether it is also affected by the ligands. The linmited experimental data, at this point consisting of only two cases for the ruthenium(II) system, lend themselves to the following evaluation. Whitten did not measure the reaction rates for the stil- bazole ruthenium(II) conplexes. Isonerization efficiency was attri-n: buted to ruthenium(II) catalyzed intersystem crossing to an unreactive triplet, evidenced by a ten fold lower sensitized isonerization effi- ciency. He attributed complexed stilbazole isonerization to a singlet reaction. _ The tentatively determined kic is comparable to values 113 observed in other singlet systems.177 Crosby et. al.178 have pro- posed that singlet and triplet spin labelling in organonetallic com- plexes is inappropriate due to orbital mixing. However, the ligand plotoreactions in the two systems apparently occur from states of different multiplicities since pyridyl ketone photoreduction is a known triplet reaction.67 It would then appear reasonable that the value of kiC will also be affected by the nature of the ligand excited state. Ryridyl Ketone Bronotricarbonylrhenium (I) Complexes The physical properties of the bromotricarbonyl rhenium(I) pyridyl ketone complexes did not restrict the pyridyl ketone used as a ligand for the photochemical studies. Dissociation of the pyridyl ketone ligand from the rhenium(I) corplex won gc annalysis allowed for direct analysis of both acetylpyridine photoproduct and ligand pyridyl ketone disappearance. However, pyridyl ketone ligand dissociation could not be detected. Unfortunately, Type II fragmentation was not observed for any of the pyridyl ketone bromotricarbonylrhenium (I) complexes . In conparison, the corresponding styrylpyridine bromotricarbonylrheniuMI) conplexes udergo ligand isonerization in a manner almost identical to that of the free ligand.53'60 The underlying reasons for the different photochemical behavior in these two conplexes are the reactive chrono- pl'ore's ability to absorb light and the nature of the lowest lying _ . excited state. Tle enhancenent of absorption at 313 mm for pyridyl ketone rhenium(I) conplexes results from additional dd transitions. If hydrochloride salt fonnation and metal coordinnation have the same effect on light absorbance of the carbonyl chronophore,only 1.4—1.7% of the light goes into the ligand carbonyl chronoplrore. Irradiation over 114 the 24 hour period (Table 20) could result in only 0.003 einstein absorption by the ligand . With no internal conversion , this would produce only 5 x 10-4 M acetylpyridine , corresponding to an observed quantum yield of 0.0015. A 10'“1 M concentration could have been mea- sured. Furthermore, the MLCT state is lower in energy than the ligand triplet excited state. Thus the lack of ligand photoreaction is a consequence of the ligand's weak absorption of light as well as conpe— titiVe conplex decorposition. In contrast, metal coordination of styrylpyridine in the rheniu:(I)lcorplex shifts the IL W ”max (meta) = 297 nm ( c 45300 M" cm' 1 ); Amax (para) = 330 nm ( E 53200 M- om-l)) but has a negligible effect on the extinction coefficient in cowarison to the free ligand ( Amax (para) = 308 nm ( E 27000 M'lcm‘l); Ammeta) = 308 nm ( c 19300 M‘lan’ln). The alkene chroroplore absorbs all the light and isonerization quantum yields and photostationary states are identical to the free ligand.53 I The color changes after irradiation are a further indication that ptotoreactions occur from the lower energy MLCT states. Normally carbon monoxide dissociation is the primary photoprocess 179,180 observed won irradiation of metal carbonyl corplexes . However , with the lack of observable CO dissociation in other bronotricarbonyl- rhenium(I) systems,61 this was not expected to be a carpeting photo: process. The absence of change in the infrared and absorption spectra implied that pyridyl ketone ligand dissociation from the conplex did not occur. Even if pyridyl ketone ligand dissociation were to occur, free pyridyl ketone Type II fragmentation would not be expected to conpete with conplexed pyridyl ketone fragmentation sinnce the rhenium 115 complex would still absorb a major amount of the light and the presence of bronotricarbonylrhenium (I) conplexes swressed fragmentation quantum yields of the free ligand in indepedent experiments (Table 6). The fact tint gc annalysis of irradiated solutions of the pyridyl ketone bronotricarbonylrhenium (I) conplexes sl'ow more disappearance of pyridyl ketone ligand than the concentration change calculated from the change in MLCI‘ Amax Optical density suggests a situation similar to that 4 observed in the pentaanmmineruthenium(II) system. Although new products are not detected by gc analysis, the broadness of the MLCT band may obscure the spectral characteristics of products with similar absorp- tion properties formed after plolonged irradiation. The lack of IL protobehavior in the pyridyl ketone tricarbonyl- bronorhenium(I) conplexes is paralleled in the emission spectra. The IL emission of l-(3-pyridyl)pentanone (3VP) is conpared to the MCI emission of Re3VP in Figure 34. Like the free pyridyl ketones, no emission is observed from the corresponding bronotricarbonylrhenium (1)” conplexes at room tenperature. At 770K the red shifted, broad, structureless emission of the para pyridyl ketone complexes is indica- tive of MLCI‘ character. The low energy emission of the meta alkyl pyridyl ketone complexes also has MLCI‘ character, unlike the ligand character seen with the correspoding benzoylpyridine conplex. The spectral properties of the pyridyl ketone bronotricarbonylrhenium(I) conplexes are conpared to tlne tricarbonylrhenium(I) systems exhibiting 11. character in their emission spectra (Table 30). The 3-valeryl- pyridine and 3-benzoylpyridine conplexes have the same absorption energies. The emission energies at 77°K are not identical for the 3-benzoylpyridine (69.2 heal)62 and acetonitrile phenanthroline 116 3 E E‘ .5; Q 460 4'50 530 .5 _ .§ ' .8 a . ,fi . M E . L 4 1 n 400 450 500 Wavelength , nnmn Fifi 34. Conparison of theemissionspectraof Re3VPannd 3VP in 5:1 methylcyclohecane : iso-pentane (—-); methyltetrahydrofuran (NH) and EPA(‘ """ ) at 77K. 117 . Table 30. Spectral properties of sone BrRe(CO) 3L2 conplexes. AbsorptionC Emission Am,mm( n, us)d -1 -l o o E lex Anax'm (e,M on ) 298 C 77 K BrRe(CO)3(3-ben2py)2a sh m 295 546(<0.5) Total: 413,444,478 (12.5 + 1300) long Lived: 413,442 a 478,518 (1300) BrRe(CO)3(4-benzpy)2 330(10000) 602(<0.5) Total: 513 (38) long Lived: none BrRe(CO)3(3VP):2 sh N 300(10050) none Total: 476 long Lived: 476 BrRe(CO)3(4VP)2 334 (10270) none Total: 493 Long Lived: 493 C1Re(CO)3phennb sh W 409 577(0.85) Total: 535 (9) b long Lived: 493 (Cl-IBCN)Re(CO)3phen 360(6410) 532 (0.80) Total: 455,487,517 (11 + 75) long Lived: 452,482 517 (75) a‘Ref. 62. bRef. 63. c:Benzene solvent. dEPA solvent. (62.9 kcal) rhenium(I) complexes, yet only those conplexes in the series with the blue shifted absorption and emission bands show structured emission at low tenperature. It is evident that a corre- lationcannotbedrawnbetweentreexistenceofILcharacterinthe emissionspectraandtheenergy levels of theILandMLCI‘ states. The absence of IL character in the pyridyl ketone rhenium(I) conplexes could also indicate that the initially populated ligand excited states udergo internal conversion to the lower energy MLCI' excited states faster than reaction from the ligand excited state. Sensitization of alkene isonerization by rhenium (I) complexes resulted in isonerization quantum yields of varying efficiency . The linear plots show a variation in the efficiency of intersystem crossing 118 dependent won the alkene quencher , aza substituent and substituent on the pyridine carbonyl group. While dependence upon the latter two factors is expected, dependence of the intersystem crossing efficiency on the quencher suggests that alkene isomerization does not occur by the accepted bimolecular nechanisnm.125 This is further sustantiated by the fact that Repy causes alkene isonerization with efficiency conparable to that observed for other metal complexes 181’182 Wrighton et.al.182 speculated that uder similar conditions . alkene isonerization resulted from the dissociation of carbon monoxide, followed by reversible binding of the alkene. Tre results described in this thesis have shown that the proto- processes of pyridyl ketones coordinated to metal atoms are very dependentonthemetal ionandthenatureoftheother ligands. Irradiation with high energy light at 313 mm does not always lead to protochemical reactions from He pyridyl ketone ligand excited state. The uderlyinng reason is tie existence of additional pathways of decay for an organic ligand, L, when coordinated to a metal ion in an organonetallic conplex. (Figure 32) . The intramolecular plotoreduction reaction from the wper excited state of the pyridyl ketone pentaanmminernrtleniumfll) conplexes is fast eough to compete with decay to the lower energy excited states. Decreased ability to absorb light directly into the carbonyl chrono- plore lovers the Type II fragmentation efficiency. Correction of 4’11 for light absorbtion and comparison to o: of the pyridyl ketorne hydro- chloride salts indicates that with coordination of the nitrogen lone pair, the same effects Operate on the 1,4—biradical. Ligand proto- substitnntion occurs only with tie meta pyridyl ketone pentaammine- ruthenium(II) conplenes from the LF* excited state. Side reactions, amoung them conplex decomposition, compete with the intermolecular ptotorednotion reaction and the rate of decay of the ligand derived triplet excited state cannnot be quantitatively lifetimes of the triplet carbonyl excited state in the pyridyl ketone 119 . 120 pentaammineruthenium(ll) conplexes were conpared to the lifetimes of the corresponding hydrochloride salts to determine a rate of decay to the lower energy excited states of less than 108 sec-l. The lack of Type II fragmentation for the bronotricarbonyl— rhenium (I) pyridyl ketone conplexes suggests that the rate of internal conversion to the lower energy states is faster than the rate of gamma hydrogen abstraction. If metal corplexation were to have the same ’ effect on excited state behavior as hydrochloride salt formation , the lifetime of the ligand carbonyl triplet state and the rate of ganmra hydrogenabstractionwouldbeexpectedtodecreaseandincreaserespec— tively. Sensitization studies show that triplet state population occurs won excitation. The decreased ability of light absorbance by the ketone chronopl'ore would result in inefficient Type II fragnenta- tion. Ligand photoreduction is then unable to compete with complex deconposition. In conclusion, reaction resulting directly from the wper excited state in an organonetallic conplex has been observed. (bservation of ligand pyridyl ketone ptotoreduction has been foud to be depedent won the ability of the ketone chroropl'ore to absorb light. Mast signnificantly , where ligand plotoreduction is efficient eough to corpete with conplex deconposition, the lifetime of the ligand excited statemaybeusedtodetenminetherateof decayoftheupperexcited state to the lower excited states. The rate of internal conversion inthe pyridyl ketone pentaammineruthenium(ll) conplexes (kic < 108 sec'ln is slower than the rate of conversion in organic compounds 11 13 sec-1).186 (Ric == 10 -10 121 Suggestions for Further Stndy The field of organonetallic plotochemistry is rich with Oppor- tunity and the results in this dissertation indicate that further work is necessary to increase understanding of the organonetallic excited state manifold. Study should be focused primarily on systems where ligands udergo reactions from wper excited states to allow further determination of the rates of internal conversion of the excited states. Now that it is established that a pyridyl ketone coordinated to a metal center can udergo Type II fragmentation before conplex deconposition, two different courses of study could be persued. Pyridylketonescouldbeusedas ligands incthermetal systems. Sinnce tie observation of photoreduction depends strongly on the ability of the carbonyl chronoptore to absorb light , irradiation of conplexes which are transparent in tie 313 nm region would be expected to provide valuable information. The second course of sttdy would be related directly to the ptotochemistry which has been observed in the ruthenium(II) system: 1) Synthesis and investigation of the protochemical pmperties of the pyridyl ketone bisbipyridylruthenium(Il) conplexes in (48) where ligand plotodissociation would not be expected to be a conpeting side reaction. _ O [Ru (bipy) ZNQAR) 2] 2+ (48) 2) Synthesis and photochemical study of tie conplexes in (49) to determine the intramolecular effect of metal coordination ontheT‘ypeIIpl‘otoprocesseswhenthemetal isnctconjugated 122 to the carbonyl chronophore. [RIJ(M13)5NWPh]2+ and [Ru(bipy) MR) 212+ (49) The low quantum efficienncies and high rates of reactivity of the pyridyl ketone hydrochloride salts indicate that these conpounds will exhibit interesting protochenistry in their own right. It is apparent that the two reactions leading to product fornmation , radical fonnation and reaction of these radicals , are in conpetition with reactions wtose nature at this point can only be ascribed to a charge transfer interaction. Further work especially involving tl'e bimolecular pl‘oto- reduction and flash experiments are necessary. MW Instrunentation All compouds were identified on the basis of their physical and spectral properties using the instrunents described below. Samples for irradiation were greater than 99.5% pure as determined from gas phase chmnatography (9c) . Nuclearresonannce spectra (NMR) at 60Mszereobtainedwitha Varian T—60 MIR Spectroprotoneter. All chemical shifts (6) are repor- ted in parts per million (ppm) dovnnfield from tetrannethylsilane (TTB) . Infrared absorption spectra (IR) were determined on a Perkin Elmer 237B Grating Infrared Spectrophotometer calibrated at 1601 on’1 with a polystyrene film. Low resolution mass spectra (me) were determined onaHitachiPerkinElmerRMU—Gmass spectmpkotoneteroronaFinnigan 4021 Cit-IVE at an ionization potential of 70 ev for electron impact and 40 ev for chemical ionization (methanne carrier gas). Melting points (up) were determined with a Thomas Hoover capillary melting point apparatus . All melting points are uncorrected. Elenental analyses were performed by Spanng Microanalytical Laboratory, Eagle Harbor, Mi- chigan 49951. Absorption spectra were measured with a Cary 17 or Unicam SP-800 spectroptotoneter. EmissionspectraweremeasuredonaPerkinElmer MPF—44A Fluorescence SpectrOpIotoneter equipped with a Differential Corrected Spectra Unnit and Hitachi Prosphorescence Accessory. Preparative scale separations were done on a Varian Aerograph 123 124 model 920 gas chroratograph fitted with a thermal conductivity detec- tor. Analytical analyses were done on Varian Aerographs : Hi-Fy Model 600D, Model l200 and Model 1400 gas chrotatographs fitted with flame ionization detectors. Relative peak areas were determined using an lnfotronics CRS 309 Conputing lntergrator for Chronatography . Chemicals Solvents Benzene: 3 . 5 liters of thicphene free benzene (Fischer Scientific or Mallinckrodt Chemical Conpany) was stirred over several changes of concentrated sulfuric acid (200 ml) until the sulfuric acid retained colorless. It was washed with distilled water (2xBOO ml) , then satura- ted sodium bicarbonate (3x300 ml) until a white precipitate no longer formed. The benzene was then washed with distilled water (2x200 ml) and dried with anhydrous magnesium sulfate. It was refluxed over plosphorous pentoxide overnight and distilled through a one meter col- umn packed with stainnless steel helices, the first and last 250 ml being discarded; bp = 80.00 c. Acetonitrile: Acetonitrile (Fischer Scientific Corpany) was 187 purified according to the procedure of O'Donnell. Practical grade acetonitrile was distilled from 10 g anhydrous Na2003 and 15 9 mo , made slightly acidic with 1412304 (conc) , decanted from the precipitated ammonium sulfate and distilled through a half meter column packed with stainless steel helices; bp = 82° c. Mallinckrodt SpectAR, Aldrich Gold label and MB OmniSolv were used as received. midine: Pyridine (Mallinckrodt Chemical Company) was dried over KOH, decanted and distilled from barium oxide-through a lnalf meter 125 columrn packed with stainnless stell helices. The middle 70% was collec- ted; bp = 115° c.188 tert-Butyl Alcohol : tert-Butyl alcohol (J. T. Baket Conpany) was distilled from freshly cut sodium (lg/ l of alcohol) through a 45 on glass helix packed column. The middle 60% was collected; bp = 83° c. Z-Nethyltetrahydrofuran : 2-Ivethyltetrahydrofuran (Mntheson , Cole- man and Bell) was refluxed overnight over cuprous chloride , then dis- tilled through a 40 on vigreux column. The first and last 10% were discarded. It was then triply distilled from lithium aluminum hydride, the first and last 10% being discarded; bp = 79°. c.189 Z-Methylbutane: Gold Label Grade 2-methylbutane was used as received from Aldrich Chemical Conpany. Ethanol: Ethyl alcohol was used as received from Aaper Alcohol and Chemical Conpany. Etm/l Ether: Annhydrous ethyl ether (Mallinckrodt) was refluxed for 24 hr over freshly cut pieces of sodium and distilled from a 30 on vigreaux column packed with stainless steel helices. The middle 60% was collected; bp = 34.5° c. When used for emission studies at 77°x, ether was distilled freshly prior to use. Emission spectrum at 77°n< showed no impurities immediately after distillation; however, with time, impurities appeared. Methyloyclohecane : Methylcyclohexane (Eastman Chemical Conpany) 190 was purified according to the procedure of Foster. 500 mnl of methylcyclohexane was stirred over several clnanges of concentrated sulfuric acid (100 ml) until the sulfuric acid retained colorless. It was washed with distilled water (3x100 ml) , saturated sodium bicarbonate (3x100 ml), distilled water (2x100 ml) and dried over 126 magnesium sulfate. It was then distilled through a half meter stain— less steel helix column. The first and last 20% was discarded; bp = 101°C. Ear: Distilled water was passed through three Sargent-Welch mixed ion-exchange columns . Hydrogen Donors Toluene: Toluene (Mallinckrodt) was purified in the same manner as benzene with the exception that the toluene was kept in an ice bath while being washed with sulfuric acid to prevent sulfonation of the ring. The middle 60% was collected from distillation; bp = 110° c. EXylene: p—Xylene (Mallinckrodt) was purified in the same manner as toluene. The middle 60% was collected from distillation; bp = 138° C. 2-Propannol: 2-Propanol (mueson, Coletan and Bell) was distilled from freshly cut metallic sodium through a 20 on glass helix packed column. The first and last 10% was discarded; bp = 825°C. l-Phenylethanol : l-Phenylethanol (Aldrich) was purified by stir- ring over sodium borohydride to reduce acetophenone, washed with dis- tilled water and distilled under reduced pressure; bp = 89° cuo mm) . Internal Standards gclohexane : Cyclohexane (Matheson , Colenan abd Bell , Spectropro— to metric grade) was recrystallized twice from itself by Dr. H. Frerking. Hecadecane: Hexadecane was obtained from Aldrich Chemical Company and purified by washing with sulfuric acid, then distilling by Dr. peter J. Wagner; hp = 146° C(lO mm) . Heptadecane: Heptadecane was obtained from Aldrich Clnenfieal 127 Corpany and purified by washing with sulfuric acid then distilling by Dr. Peter J. Wagner; bp = 158° C(8 mm) . Octadecane: Octadecane was obtained from Aldrich Chemical Conpany' and purified by recrystallization from ethanol by Dr. Peter J. Wagner. Nonadecane: Nonadecane was obtained, from Chemical Samples Company and purified by recrystallization from petroleum ether by Dr. Peter J. Wagner. Eicosane: Eicosane was obtained from Chemical Samples Conpany and purified by recrystallization twice from 200 proof ethanol by Elizabeth Seibert. Heneicosane: Heneicosane was obtainned from Chemical Samples Conpany and purified by recrystallization from ethanol by Dr. Peter J. Wagner. Quenchers 2,5-Dimethyl-2L4-hexadiene: this diene was obtained from Chemical Samples Corpany and upon refrigeration sublimed w aroud the sides of the bottle. The sublimed material was used. cis- and trans-14 3-Pentadiene: this diene was used as received from Clnemical Samples Conpany. cis-1,3-Pentadiene: this diene was used as received from Chemical Samples Company (98.8% pure by go). trans-Stilbene: this olefin was used as received from J. T. Baker Company. Ethyl sorbate: this diene was used as received from Aldrich Chemi- cal Conpany. N_aphthalene: Naphthalene (batheson, Colenan and Bell) was purified by several recrystallizations from ethanol by Dr. A. E. Puchalski; up = 128 79.5-80.5° c. Phem/lalkyl Ketones AcetOphenone: Matheson, Colenan and Bell acetOphenonne was distilled uder reduced pressure by Dr. A. E. Puchalcki. BenZOphenone: Aldrich Chemical Conpany benzwhenone was purified by recrystallization from ethanol by W. B. Mueller. Valerophenone : Valerophenone was prepared by the Friedel Crafts acylation of benzene by valeryl chloride . The acid chloride was drip— ped slowly into a two-fold excess of benzene containing a ten percent excess of aluminum chloride and refluxed one hr. Upon cooling, the mixture was poured onto cracked ice and conncentrated I-Cl , the layers separated and the aqueous layer was washed with benzene. The corbined organic layers were washed with 5% NaOH (100 ml) and saturated sodium chloride solution .'_ (100 ml). Renoval of the solvent uder reduced pres- sure gave a brown oil (85%) . Two distillations gave 99.7% pure product bp = 88° c (1.2 mm). Pyridylalkyl Ketones -- 2-Aceglpyridine (ZAP): 2—Acetylpyridinne (Aldrich Clnemical Conpa- ny) was distilled; bp = 65° C(lO mm) . physical properties: IR(neat) 3040, 2970, 1700, 1585, 1565, 1350, 1275, 1230, 1100, 970 om-l; NMR (c0013) 62.68 (s, 1H), 7.21-8.67 (m, 4H, aronatic); UV(acetonitrile) 1cm'1); m/e (rel int) 121(65), 93(23), 79 (100), 781 275 mm (s 2810 M' (79). 3-Acetylpyridine:(.BAP): A solution containing (20 g (0.14 m) of methyl icdidein80mlofanhydrousetherwasaddeddropwisetoawell stirred mixture of 3.5 g (0.14 m) of magnnesium turninngs and 20 mnl of annhydrous ether. When themixture cooled to room tenperature, a 129 solution containing 10.4 g (0.10 m) of 3-cyanopyridine in 80 ml of ether was added dropwise, then the mixture was refluxed for 12 hr. Upon cooling to room tenperature, 100 ml of a 5% sulfuric acid solution was added, the ether was renoved by distillation and the reaction mix- ture was refluxed 1.5 hr. Upon cooling, the solution was saturated with solid potassium carbonate and extracted several times with ether. The ether extracts were contained, washed with saturated salt solution and dried over magnesium sulfate. Renoval of ether under reduced pre— ssure left a brown oil ( crude yield 10 g - 83%) which was distilled; bp = 89—9o° C(7 mnm) , and characterized as 3-acetylpyridine on the basis of its physical and spectral prOperties: IR(neat) 3010, 1700, 1590, 1420, 1370, 1275, 1015, 800, 700 cn"l ; NMR(CDC13) 62.57 (s, 1H), 7. 29- 9. 05 (m, 4H, aronatic); UV(acetonitrile) 266 mm (s 2510 M 1-om 1); m/e (rel int) 121(54), 106(97), 79(17), 78(100); UV(heptane) 267 nm (e 2630 M-lom-l). 4-Acetylpyridine (4AP): A solution containing 20 g (0.14 m) of methyl iodidein80mlofannhydrousethermasaddeddropwisetoawell stirred mixture of 3.5 g (0.14 m) of magnesium turnings and 20 ml of anhydrous ether. After the reaction was conplete, a solution of 10.4 g (0.10 m) of 4-cyanopyridine in 100 m1 of anhydrous ether was added dropwise. The resultant solution was refluxed 12 hr. Upon cooling, 100 ml of 5% aqueous sulfuric acid solution was added and the reaction mixture was refluxed 1.5 hr. Upon cooling, the solution was saturated with solid potassium carbonate and extracted with ether. The ether ex- tracts were conbined , washed with saturated salt solution and dried overanhydrouspotassiumcarbonate. Renovalof theetherunder reduced pressure left a brown oil (crude yield 5. 2 g - 41%) which was distilled; 130 bp = 108-110° C(25 mm) , and identified as 4-acetylpyridine on the basis 191 of its physical and spectral properties: IR(neat) 3020, 1700, 1600, 1560, 1415, 1272, 810 cm-l; NMR(CIIIlB) 62.6 (s, 3H) 7.38-8.57 (dd, 4H, 1 aronatic); UV(acetonitrile) 279 mm (a 2210 M. cm-l); UV(heptane) 278 1cm'l); m/e (rel int) 121(94), 106 (100), 79(29), 78(77), m (c 2240 M” 51(35) . l-(2-pyridyl)butanone (ZBP) : A solution containing 35.2 g (0.29 m) of g-prOpyl bromide in 80 m1 of annhydrous ether was added dropwise to a well stirred mixture of 6.9 g (0.28 m) of magnnesium turnings and 30 ml of annhydrous ether. After the reaction subsided, it was cooled to and kept at 2°C while a solution containing 30 g (0.29 m) of 2-cyanopyri- dinein80mlof anhydrous etherpasaddeddrogwiseoveraperiodof two tours. The resultant black solution was stirred uder reflux 12 hr. Upon cooling, the black solution was poured into 200 m1 of 10 M hydrochloric acid. The ether was renoved by distillation and the reaction mnixture pas refluxed for 8 hr. Upon cooling, the solution was made basic by the addition of solid potassium carbonate. Filtra- tion renoved the precipitated salts and the precipitate was washed with ether. The aqueous solution pas extracted with ether until the ether extracts were colorless. The ether extracts were conbined, washed with saturated salt solution , dried with annhydrous potassium carbonate and filtered. Renoval of the ether uder reduced pressure left a black oil (crude yield - 42.1 g - 97%) which pas distilled twice under reduced pressure to obtain a sample suitable for pl'otolysis. The ketone was identified as 2-butyrylpyridine on the basis of its physical and spectral characteristics: bp = 85-87° C(4.5 mm); IR(neat) 3040, 2970, 1 1700, 1585, 1565, 1350, 1275, 1230, 1100, 970 cm— ; NMIRKIIIIB) 60.98 131 (t, 3H), 1.45-2.03 (m, 2H), 3.1 (t, 2H), 7.2-8.7 (m, 4H, aronatic); lam-l); m/e (rel int) 149(48), 134 UV(acetonitrile) 267 mm (c 4190 M” (100), 121(62), 80(45), 79(90), 78(57), 51(64). l-(3—pyridyl)butanone (3BP) : A solution of 23.6 g (0.19 m) of g-prOpyl bromide in 80 ml of anhydrous etl'er pas added dr0pwise to a well-stirred mixture of 4.7 g (0.19 m) of magnesium turnings in 20 m1. of anhydrous ether. This solution of p—propylmagnesium bromide pas added dropwise to a stirred solution cantaining 20 g (0.19 m) of 3-cyanopyridine in 80 ml of anhydrous ether and 20 ml of benzene. The reaction mixture was stirred at 25°C for 3 hr. The reaction pas quenched by the addition of 200 ml of 10 M hydrochloric acid solution. The ether pas removed by distillation and the reaction mixture was refluxed for 3 hr. Upon cooling, the solution pas made basic by the addition of solid potassium carbonate. Filtration renoved the precipi- tated salts and the precipitate pas washed with ether. The aqueous solution pas extracted with ether until the ether extracts were color- less. The ether extracts were conbined, washed with saturated salt solution, dried with annhydrous potassium carbonate and filtered. Re- moval of the ether uder reduced pressure left a brown oil (crude yield 28 g - 100%) which pas distilled twice under reduced pressure followed by a spinnnninng band distillation uder reduced pressure to obtain a sample suitable for photolysis. The ketone pas identified as 3-butyry1pyridine on the basis of the following data: hp = 101-102° c (1.9 mm); IR(neat) 3040, 2960, 1690, 1585, 1420, 1220, 1010, 800, 700 cm-l; mn(cm13) 61.0 (t, 3H), 1.74 (m, 2H), 2.92 (t, 2H), 7.59-9.42 (m, 4H, aronatic); UV(acetontrile) 266 nm (e 4300 m‘lcm'ln; UV(heptane) l 276 mm (s: 4100 M. CHI-l); m/e (rel int) 149(4), 121(2), 106 (91) , 78(100) . 132 l- (4-pyridyl)butanone (4BP): A solution containing 59 g (0.48 m) of g-pmpyl bromide in 80 ml of anhydrous ether pas added dropwise to a well stirred mixture of 11.7 g (0.50 m) of magnesium turnings and 30 ml of anhydrous ether. After the reaction subsided, a solution containing 25 g (0.24 m) of 4-cyanopyridine in 60 ml of anhydrous ether and 40 ml of benzene was added to the stirred solution over 5 mnin. The resultant mixture pas refluxed with stirring for 7 hr. Upon cooling, it pas poured into 200 ml of 10 M hydrochloric acid solution, then. refluxed 12 hr. Upon cooling, the solution was made basic by the addi- tion of solid potassium carbonate. Filtration renoved the precipitated salts and the precipitate was pashed with ether. T‘Ie aqueous solution pas extracted with ether until the ether extracts were colorless . The ether extracts were conbined, pashed with saturated salt solution, dried with annhydrous potassium carbonate and filtered. Removal of the etlner uder reduced pressure left a brown oil (crude yield 33 g - 93%) whichpasdistilledthreetimesunder reducedpressuretoobtaina sam- ple suitable for photolysis. The ketone pas identified as 4—butyryl- pyridine based on the following data: bp = loo-102° C(4 mm) ;191'192 IR 1 (neat) 3040, 3010, 2960, 1698, 1550, 1415, 1220, 800, 750 cm- ; NMR( (CIElB) 60.98 (t, 3H), 1.8 (m, 2H), 7.56-8.4 (m, 4H, aronatic); UV 1 1 (acetonitrile) 275 m (c 1640 M" cm’l); UV(heptane) 277 nm (e 1890 M’ orn-1); m/e (rel int) 149(33) , 121(31) , 106 (100) , 79 (16) , 78(80) , 51 (45). l-(Zjnyridylmentanone (2VP) .pas synthesized by the general metnod used for 1—(2-pyridyl)butanone using 27.5 g (0.20 m) of n_n_-bronrbutane, 4.8 g (0.21 m) of magnesium turnings and 21.2 g (0.20 m) of 2-cyan0py- ridine. The synthesis gave a black oil (crude yield - 29 g - 88%) which pas distilled twice uder reduced pressure to give a sample pure 133 enough for plotolysis . The ketone pas identified as 2-valerylpyridine on the basis of the following data: bp = 92-93°c (4.3 mm); IR(neat) ' 3040, 2960, 1700, 1580, 1210, 1015, 760 cm'l: (NDGR(C11213) 60.95 (t, 3H), 1.56 (m, 4H), 3.141(t, 2m, 7.19-8.6 (m, 4H, aronatic); UV(acetonitrile) lam-l); m/e (rel int) 163(13) , 134(35) , 121(59), 106 267 mm (c 3670 M" (88), 79(74), 78 (100), 51(38). l-(3—13yridyl)pentanone (3VP) pas synthesized by the general metlod used for l—(3.—pyridyl)butanone using 26.3 g (0.19 m) of g—brondautane, 4.7 g (0.19 m) of magnesium turnings and 20 g (0.19 m) of 3-cyanopy- ridine. The synthesis gave a brown oil (crude yield - 45 g - 99%) which pas distilled twice uder reduced pressure to give a sample suit- able for photolysis . The ketone pas identified as 3-valerylpyridine based on the following data: bp = 114-115° C(2 mmn); IR(neat) 3040, 1690, 1585, 1420, 1270, 1220, 1010, 790, 700 cm—l ; NMR(CDC13) 50.95 (t, 3H), 1.59 (m, 4H), 2.94 (t, 2H), 7.18-8.71 (m, 4H, aronatic); UV (acetontrile) 266 nm (e 3350 m'lcn‘ln; UV(heptane) 267 nm (13225—1511. om-l); m/e (rel int) 163(8) , 121(81), 106(100), 78 (78), 51(32). 1- (4-Pyrgygpentarme (4VP) pas synthesized by the general metlod used for 1-(4-pyridy1)butanone using 79 g (0.58 m) of g-butylbromide, 14 g (0.59 m) of magnesium turnings and 30 g (0.29 m) of 4-cyanopyri- dine. The synthesis gave a brown oil which pas distilled (crnde yield 45 g - 99%) twice under reduced pressure to give a sample suitable for pl'otolysis. The ketone was identified as 4-valery1pyridine191'192 based on the following data: bp = 114-115°C (4m; IR(neat) 2950, 2930, 1 2875, 1700, 1550, 1400, 1205, 1200, 805, 780 on. ; NMR(CIIZI3) 60.94 (t, 3H), 1.83 (m, 4H), 2.94 (t, 2H), 7.37-8.56 (dd, 4H, aronatic); UV 1 1 (acetontrile) 276 m (e 2075 14" cum-1); UV(heptane) 277 nm (e 2150 M" 134 cm-l); m/e (rel int) 163(20), 121(100), 106(90), 77(16), 78 (66). 4—Methyl-l—(2-pyridyl)pentanone (yMeZVP) pas synthesized by the general metlod used for l-(2-pyridyl)butanone using 43 g (0.28 m) of l—brono-3-methylbutane, 6.9 g (0.29 m) of magnesium turnings and 30 g (0.29 m) of 2-cyan0pyridine. The synthesis gave a black oil (crnde yield 40 g - 88%) which was distilled three times uder reduced pres- sure to give a sample suitable for plotolysis. The ketone pas charac- terized as yMe2VP on the basis of the following data: bp = 103-104° c (2.3 mm); IR(neat) 3040, 2960, 1690, 1580, 1460, 990, 750 om-l; NMR (C1113) 60.95 (d, 6H), 1.65 (t, 3H), 3.2 (d, 2H), 7.25 - 8.3 (m, 4H, 1 aronatic); UV(acetonitrile) 270 mm (s 3585 M. om-l); UV(benzene) 277 1arm-l); m/e (rel int) 177(2) , 163(3) , 149(1), 134 (43) , nm (a 2980 M- 121(28), 106 (30), 93(17), 80(18), 79(100), 78 (84). 3-1‘et1yl-l-(3—pyridynbutanone (BMeBBP) pas synthesized using the general metlod used for l-(3-pyridyl)butanone using 39 g (0.29 m) of l-brono-Z-methylpropane, 6.9 g (0.29 m) of magmium turnings and 30 g (0.29 m) of 3-cyanopyridine. The reaction gave a yellow oil (crude yield 33 g - 70%) which pas purified by distillation under reduced pressure, repeated recrystallization from the hydrochloride salt from methylene chloride and g-pentane and finally‘a spinning band distilla- tionofthefreeketoneuderrednoedpressure. T‘heketonepascharac- terized as 8re38p based on the following data: bp = 104° C(2.4 mm); IR(neat) 3040, 2960, 1690, 1580, 1410, 1360, 1270, 1210, 970, 775, 690 cm'l; money 60.9 (s, 3H), 1.3 (s, 3H), 2.25 (m, 1H), 2.8 (d, 2H), 1 7.12-8.7 (m, 4H, aronatic); UV(acetonitrile) 266 nm (e 2070 m“ cm’ln; . m/e (rel int.) 163(8) , 148(8), 106 (100) , 79 (11) , 78 (62) , 51(32) . B-betlyl-l-M-gridylmutanone (BMe4BP) pas synthesized by the 135 general method used for 1-(4-pyridyl)butanone using 41 g (0.30 m) of l-brono-Z-methylpropane, 7 g (0.30 m) of magnesium turnings and 31 g (0.30 m) of 4-cyan0pyridine. The reaction gave a brown oil (crude yield 43 g - 88%) which pas distilled three times uder reduced pres- sure . The ketone was converted to the corresponding hydrochloride salt and recrystallized twice from methylene chloride and _n—pentane to give a sample suitable for photolysis. The ketone pas characteri— zed as BIVE‘IBP on the basis of the following data: bp = 116° C (5.5 mm); IR(neat) 3020, 2950, 1695, 1585, 1395, 1250, 1185, 970, 800 cm-1; NMR (C11213)6 1.1 (d,6H), 2.3 (m, 1H), 2.8 (d, 2H), 7.62-8.7 (m, 4H, aro- matic); UV(acetonitrile) 275 mm (c 2170 m'lcm'ln UV(heptane) 273 nm 1(Hm-l); m/e (rel int) 163(30) , 148 (13) , 122(8), 121 (80) , 107 (e 2250 M- (9), 106 (100), 79(22), 78 (64), 57(26). 4—l'ethyl-l- (2—pyridyl)pentanone (me4VP) was synthesized by the general metrod used for l-(4-pyridyl)pentannone using 87 g (0.58 m) of 1-brono-3-methylbutanne, 14 g (0.61 m) of magnesium turnings and 20 g (0.60 m) of 4-cyanopyridine. The reaction gave a brown oil ( crude yield 31.5 g - 93%) which pas distilled four times uder reduced pres— sure to give a sample suitable for photolysis. The ketone pas charac- terized on the basis of the following data: bp = 97-99° c (2.2 mm); IR 1 (neat) 3020, 2960, 1690, 1405, 1270, 1200, 980, 810 cm- ; NMR(CIIZ1 3) 6 0.91 (d, 6H), 1.6 (m, 3H), 2.9 (t, 2H), 7.5-8.7 (m, 4H, aronatic); 1gun-1); UV(heptane) 278 mm (c 2300 UV(acetonitrile) 277 mm (c 2310 M— M'lcm-l); m/e (rel int) 177(9), 122(38), 121(100) , 106(98), 93 (13), 78 (70), 51(53). Iyridyl Ketone Hydrochloride Salts All hydrochloride salts were prepared by bubbling hydrogen 136 chloride gas through an ether solution of the pyridyl ketones . The salts were purified by repeated recrystallization from methyl- ene chloride and _n-pentane, washed with ether and then dried uder vacuum. All salts were greater than 99.5% pure by go analysis on Column B. 2-Acetylpyridine_hydrochloride (2API—I21): 100° c, decomposes; IR(KBr) 3040, 2975, 1700, 1590, 1350, 1270, 1230, 1100, 975 (mm-1 1 1). 3-Ace_ty1pyridine hydrochloride (m1) : 160° c, decomposes; IR(KBr) 1 ; UV (acetoni- trile) 273 nm (e 2930 14" cm" 3010, 1700, 1600, 1565, 1420, 1370, 1270, 1000, 800, 700 cm- 1 1). 4-Acetylpyridine_hydrochloride (4Apnr21): 100°C, deconposes; IR(KBr) 1 ; UV(ace- tonitrile) 264 nm (e 4230 m' cm- 3020, 1700, 1600, 1565, 1410, 1270, 810 cm- ; UV(acetonitrile) 278 l rm (8 4210 M’ om-l) . 1- (2-Pyridyl)butanone hydrochloride (28mm) : up = 76-78°c; IR(KBr) 3040, 2960, 1695, 1575, 1440, 1215, 980, 760 can-1 274 rm (6 2840 n‘1 '1. 3 UV (acetoni trile) l-(3-Pyridy1)butanone hydrochloride (3BPI-Cl) : up = 135—136° c; IR(KBr) 3040, 2960, 1695, 1590, 1420, 1220, 1010, 800, 700 arm-1 1 ; UV (acetoni- trile) 262 mm (c 4125 M’ om-l) . 1- (4-Pyridyl)butanone hydrochloride (4BPI-Cl): mp = 162-163° c; IR(KBr) 3040, 2960, 1700, 1555, 1420, 1220, 800, 750 can-1 lonn-l) . ; UV(acetonitrile) 273 nm (a 3050 M’ 1-(2-gyrigglnpentanore hydrochloride (zvmcl): up = 89-90° c; IR(KBr) 3040, 2960, 1700, 1580, 1210, 1020, 770 cm.“1 1 ; UV(acetonitrile) 273 mm ( c 2910 M" cn’l) . l-(3-Pyridyl)pentanone hydrochloride (3VPI-Cl) :. up = 128-1290 C; IR(KBr) 137 3040, 1690, 1580, 1420, 1270, 1010, 800, 700 (In-1 1 1). 1- (4-Pyridyl)pentanone hydrochloride (4VPIC1): mp = 153—154° c; IR 1 ; UV (acetonitrile) 265 rm (8 4600 14" cm" (KBr) 3040, 2960, 1700, 1580, 1210, 1020, 770 cm- 1 1). 4-Methyl-l- (2—pyridyl)pentanone hydrochloride (yMeZVPI-ICl) : mp = 9'7--98o C; IR(KBr) 3040, 2960, 1695, 1580, 1460, 980, 780 (In-1; UV 1 ; UV (acetonitrile) 272 nm (e: 3880 14’ cm" (acetonitrile) 274 nm (e 2890 M' om’l) . 3-Methy1-1— (3—pyridy1)butanone hydrochloride (BMeBBPKZl) : mp = 129- 1300 C; IR(KBr) 3040, 2960, 1690, 1580, 1410, 1350, 1210, 970, 780,- 700 om'l; UV(acetonitrile) 263 m (e 4320 m’lcm'l) . 3-Methyl-l-(4-pyridyl)butamne hydrochloride (BMe43PICI): up = 170- 1710 C; IR(KBr) 3020, 1700, 1590, 1400, 1250, 1180, 970, 800 (In-l; UV(acetonitrne) 273 nm (e 3900 M'lcm'l) . 4-Methyl-1- (4-pyridyl)pa1tanone lydrochloride ti (yMe4VPH21) : mp = 159-161° C; IR(KBr) 3020, 2960, 1690, 1400, 1270, 1200, 990, 800 cm— 1 1 UV(acetonitrile) 273 min (a 3850 M” cm'l) . Photoreduction_products Bibengl: Bibenzyl (Aldrich) was used as received. 3131' lyl : l , 2-Di-p-toly1ethane (Aldrich) was used as received . 2,3—Diplmyl-2,3-butanediol: was synthesized and purified by Dr. M. J. Thales. 2,3-di(4-Pyridy1 Woride)-2,3-butane diol: NMR(D20) 62.1 (s, 6H), 3.5 (s, 1H), 7.4-8.7 (m, 10H, aronatic); m/e (rel int) 245 (27), 123 (100), 122 (60), 121(7), 108 (14), 106(24), 80(22): mp = 188- 190° c. 2,3-di(4—ggridy1)$3-hutanedio1: mp = 191-195° c; insoltble in o I 138 (11213 and D20; m/e (rel int) 245(47) , 123(100), 122(58) , 121(11) , 106 (16). 2,3-‘di(3-Pyridyl hydrochloride) -2,3-butanediol: mp = 193-194° C; NMR(CIIZl3) 62.1 (3,611), 3.3 (s, 1H), 7.3-9.1 (m, 10H, aronatic); m/e (rel int) 245(33), 123(100), 122(64), 121(9), 108(15). 2,3—di(3-Pyridyl)-2,3-—butanediol: mp = 197-199°C; insoluble in Girl and D20; m/e (rel int) 245(45) , 123 (100), 122 (56) , 120(15), 106 3 (23) . Ruthenium Carplexes Unless otherwise noted, all operations were performed in a puri- fied argon atmosphere and all solvents were degassed prior to use. 'No methods were used for argon purification: Method 1: A chramus bubbler made by the reacticn of an aqueous solution of 1 M chrcml'c chloride with mossy analganated zinc.193 Method 2: A oolum of BASF Catalyst R-3-ll heated at 150°C followed in line by a column of 4 R mlecular sieves. Chloropentaamru’nerutheniuMIIDdichloride [Ru (NH3) 5C1] [C112 194 ,195 Method 1: Nitrogenpentaamninerutl'xeniuMII) [R1.1(I\II-13)5N2]2+ : Ruthenium trichloride (Alfa—Ventron) (1.97 g, 9.5 ml) was dissolved in 20 m1 of distilled water under nitrogen at 25°C. Hydrazine hydrate (13.6 g, 0.27 m) was added dropwise over a period of 20 min. The dark red solution was stirred 12 hours, thal used in the following step. ChloroPentaamnineruthenium (III) dichloride : Concentrated hydrochloric acid was added dropwise to a filtered solution of [Ru(NHB)5N2]2+ until the pH was equal to 2. The solution was refluxed with stirring and became yellow, slowly precipitating yellow product. When no ,(‘ 139 further precipitation was observed, the mixture was cooled to 2°C and filtered. The precipitate was washed with 5 m1 of 6 M hydrochloric acid, ethanol and acetone; cruie yield - 1.3 g - 47%. Recrystalliza- tim: An aqueous slurry of product in 5 m1 of distilled water was heated to 60°C . Concentrated amoniun hydroxide was added dropwise until the yellow conplex dissolved to give a wine red solution which was filtered hot, then cooled in an ice bath. Concentrated hydro- chloric acid was added dropwise to reprec ipitate a mustard yellow product which was filtered, then washed with 5 ml of 6 M hydrochloric acid solution, water , ethanol and acetcme and dried at 78°C over phos- phorous pentoxide in vacuum; yield - 0.622 g - 28% based on R1121 156,198 3. Method 2 : HexaamtineruthaiiuMIII) trichloride (Stran Chemical Inc.) (2.0 g, 6.5 nmol) was dissolved in 70 ml of 6 M hydrochloric acid solution with warming. The solution was refluxed for 4 h. , during which a yellow precipitate formed. The mixture was cooled and filtered. The precipitate was washed with 10 ml of 6 M hydrochloric acid solution, then methanol and dried under vacuum. Yields of bright yellow crystals ranged from 66-88%; UV(H20) 327 nm (e 1930 M'1 ’1); IR(KBr) 3100-3300, 1600, 1300, 700-800 cm'l. Pentaamninepyridinerutheniun (II) tetrafluoroborate and the pyri- dine substituted derivatives : These conplexes were synthesized by a 42 ,156 modification of Ford and Taube's methods. General synthetic procedure: Silver oxide (158 mg, 0.683 ml) was dissolved in 4 ml of distilled water by the dropwise addition of tri- fluoroacetic acid with stirring . Chloropaitaanminerutheniun (III) di- chloride (200 mg), 0.683 ml) was added. The resultant mixture was stirred, then digested (heated to boiling to canplete the precipitation 140 of silver chloride). After 20 min. the precipitate was filtered, then washed with two -5 ml portions of distilled water. The filtrate was diluted to 25 ml with distilled water and placed in an addition funnel. The pyridyl ketone ligand, in 3-10 molar excess, was flushed with argon in a 3-neck 100 ml round bottam flask covered with aluminum foil. When necessary, 2 ml of methanol was added to improve ligand solubility in the resultant aqueous soluticm. Granular zinc (50 g) was washed with 50 ml of 1.2 M hydrochloric acid solution. A mixture of 50 g of granular zinc, 5 g of mercuric chloride, 5 ml of sulfuric acid and 150 ml of distilled water was stirr' ed for 10 minutes.193 The zinc mercury amalgam was washed with distilled water until the washings were slightly acidic , then packed into a colum. The water was drained and the column was flushed with argon for 5 minutes. The column was fitted to the round bottomed flask and the addition funnel containing the ruthenium(III) solution was attached to the top of the column. The entire system was flushed with argm for 10 minutes. The light yellow ruthenium(III) solution was passed through the reducing column over a period of 30 minutes, giving a deep yellow ruthenium(II) solution which was slowly added to the stirring ligand. After the addition was complete, two 10 ml portions of distilled water were passed through the colum. Stirring was continued for 30 min and then ammonium tetrafluoroborate (72 mg, 0.683 mmol) was added directly to the flask. The resultant solution was refrigerated for a mu'nimum of 12 hr. The water was then removed under reduced pressure. The resultant oil or precipitate was dissolved in 3 ml of acetone. This solution was added dropwise to 400 ml of anhydrous ether which was 141 being bubbled with argon , the resultant precipitate was immediately filtered. The precipitate was dried under vacuum for 12 hr, then stored in a vacuum dessicator at 3—40 C. Purification procedure Method 1 - Column Chrcmatography: Pentaammunell-(4-pyridyl)penta- nonelrutheniuMII) tetrafluoroborate (R114VP) was chramatographed on a 2.5 x 15 cm alumina column (80-200 mesh). Fraction Elution Solvent Volure (ml) 1 . benzene l7 2 benzene 22 3 1:1 benzene : methylene chloride 40 4 1 :1 methylene chloride : acetonitrile 40 5 acetontrile 65 6 1:1 acetonitrile : methanol 40 7 methanol 60 Method 2 - Reprecipitation: the metal-pyridyl ketone complex was dissolvedinaminirmxmamomntof acetoneandaddeddropwisetoanhy— drous other using the same method as original complex isolation. Method 3 - Recrystallization: The metal-pyridyl ketone complex was dissolved in a minimum amount of distilled water and heated to 40°C. Two ml of a saturated aqueous solution of ammonium tetraflmroborate was added dropwise and the solutian was refrigerated to induce crystal- lization. PentaammineyridinerutheliuMII) tetrafluoroborate (Rupy) was synthesized using 200 mg (0.683 mnol) [RL1(I\IH;,,)5C1][C1]2 and l g (12.6 mmol) of pyridine; crude yield of mustard yellow solid - 224 mg (85%); 142 l UV(water) 408 rm (6 4580 M. C'm-l) . Catplex was recrystallized twice frtm acetone/ethyl ether to yield 50 mg (19%); UV(water) 407 nm (e 1 1 cm‘l) 244 mm (s 4190 M’ cm'l); IR(KBr) 3150-3450, 1600, 1275, 1 6270 M" 1050-1150, 750 cm . Ana1. calod. for RIIZSNGHZOBZFB: C, 13.68; H, 4.55: N, 19.15. Found: C, 13.79, H, 4.29,; N, 19.10. Pentaammine (2-aceglpyridine) ruthenium (II) tetrafluoroborate (RuZAP) was synthesized using 200 mg (0.683 mmol) of RI.1(1\II~I3)5C1][Cl]2 and 300 mg (3.8 m01) of 2—acetylpyridine; cnrie yield of blue solid - 1 262 mg (85%); UV(acetonitrile) 624 nm (e 4550 M' cm’l) 387 nm (e 3540 1 1 (In-1) 273 rm (6: 7835 M. cm-l); IR(KBr) 3150-3300, 1675-1665, 1640- 1615, 1470, 1050-1125 cmfl. M- Pentaam'mine (3-acetylpyridine) ruthenium (II) tetrafluoroborate (RuBAP) was synthesized using 200 mg (0.683 mmol) of [RI.1(NI-13)5Cl][C1]2 and 300 mg (2.5 mmol) of 3-acetylpyridine; crude yield of broom solid - 1 290 mg (92%) ; UV(acetonitrile) 412 nm (e 3350 M’ om'l) 258 nm (e 3750 lam—l) 223 nm (e 6740 M’1 1620, 1425, 1100 an'l. M" (rm-1); IR(KBr) 3200-3300, 1685-1665, 1640- Pentaammine “acetylpyridine ruthenium (II) tetrafluoroborate (Ru4AP) was synthesized using 200 mg (0.683 mmol) of [Ru(NH3)5C1][C1]2 and 300 mg (2.5 mmol) of 4—acetylpyridine; crude yield of purple solid - 320 mg -- (99%) UV(acetonitrile) 505 nm (6: 11450 m’lcn'l) 266 nm (e 4035 lam—1); IR(KBr) 3200-3300, 1675-1665, 1590, 1475-1500, 1400-1425, 1075, 875 cm’l. M- Pentaammine [l- (2-pyridyl) pentanone] ruthenium (II) tetrafluoro- borate (RuZVPi was synthesized using 200 mg (0.683 mmol) of [Ru(lNlI‘IB)5C11C1]2 and 350 mg (2.1 mmol) of 1-(2-pyridyl)pentanone; crude yield of blue solid - 247 mg (69%); UV(acetanitrile) 625 mm (a 3010 143 M'lcm'l) 382 nm (e 2565 M'lom’l) 272 mm (s 6200 M'lcm‘l) . Complex was recrystallized from water two times. Anal. Calcd. for RLCION6HBIOBZF8: C, 23.0; H, 5.4, N, 16.1. Found: C, 20.8; H, 3.4; N, 12.1; IR(KBr) 3150-3300, 1667, 1475-1500, 1400-1425, 1075, 875 cm-1. Pentaammine [l- (3-pyridylmentanone] ruthenium (II) tetrafluoro- borate (Ru3VP) was synthesized using 200 mg (0.683 mmol) of [Ru(NH3)5C1] [C1]2 and 400 mg (2.5 mmol) of l-(3-pyridy1)pentanone; crude yield of brown solid — 156 mg (46%); UV(acetonitrile) 410 nm (e -l 01 1 562 M cm ) 290 nm (e 680 M. (In-l) . Complex was reprecipitated twice from acetone/ethyl ether, UV(acetonitrile) 412 nm (e 4460 M-1 l l cm'l) 257 nm (e 4780 m“ cm'l) 223 nm (e 9990 M' om’l) . Anal. Calcd. for RtfiloH3lN6)B2F8: C, 23.0; H, 5.4; N, 16.1. Found C, 13.5; H, 3.8: N, 14.8. Complex for photolysis studies was synthesized using powdered' mercuric chloride for the zinc mercury amalgam and recrystallized frcm 1 water-ethanol, UV(acetonitrile) 412 nm (e 4760 M” cm'l) , 258 nm (e 1 1 6930 M‘ om‘l) 224 mm (8 10300 M’ cm‘l). Anal. Found: C, 23.4 and 23.37; H, 4.31 and 4.47; N, 12.80 and 12.66; IR(KBr) 3150-3300, 1680-1665, 1400-1425, 1050-1100 an'l. Pentaammine [l- (lljyridylmentanond ruthenium (II) tetrafluoro- borate (Ru4VP) was synthesized using 200 mg (0.683 mmol) of [Ru(NI-I3)SC1] [Cl]2 and 400 mg (2.5 mmol) of 1-(4-pyridy1)pentanone; crule yield of deep purple solid - 322 mg (95%); UV(acetonitrile) 1 lcxmul) . Complex was recry- 506 nm (e 9680 M" om’l) 268 nm (e 2630 M" stallized fram hater twice, yield - 58 mg (17%); mile (rel int) 163 (0.7), 490.00). Anal calcd. for RIJN6C10H3ICB2F8: C, 23.0; H, 5.4; N, 16.1. Found: C, 22.7; H, 4.5; N, 13.8. Catplex for photolysis studies was recrystallized from water/ethanol, UV(acetanitrile)- 503 144 1 cm-l) 268 nm (e 2980 14‘1 1 nm (6: 11400 14' cm' ). Anal. Found: C, 21.88 and 22.04; H, 4.89 and 4.99; N, 14.52 and 14.70; IR(KBr) 3200-3300, 1670, 1600, 1275, 1200, 1050-1075 cm-l. Pentaammine [4-methLl-1- (Z—pyridyl) pentanone] ruthenium (II) tetra- fluoroborate (RuyMeZVP) was synthesized using 200 mg (0.683 mmol) of [Ru(NH3)5Cl] [C112 and 340 mg of 4-methyl-l-(2-pyridy1)pentanone; crude yield of blue solid - 246 mg (71%) . Camplex was recrystallized frum water and found to be insoluble in acetonitrile; UV(water) 650 nm (e 890 M'1cm'1) 376 nm (e 770 m’1cn’1) 274 nm (e 2125 n'1cn'1). Pentaammine [3-methyl-l- (3-pyridy1)butanone] nrthenium (II) tetra- fluoroborate (RuBMeBBP) was synthesized using 200 mg (0.683 mmol) of [Ru(NHB)5C1] [C112 and 360 mg (2.2 mmol) of 3-methyl-1-(3-pyridyl)buta- none; crude yield of brown solid - 419 mg (89%) . Complex for photoly- sis studies was recrystallized frum water/ethanol, UV(acetcnitrile) 1 1cm’1); UV(water) 412 nm (e 1on’1); IR(KBr) 3200-3350, 1675, 1400-1425, 1275-1300, 1175-1200, 1025-1075 (In-.1. cn’1) 259 (e 6020 m' 1 415 nm (e: 4700 14' 1 cn'1) 227 nm (e 7720 M" 4710 M" om'1) 259 nm (e 5330 M" Pentaammine [ 3-methyl-l- (4miq1) butanale] ruthenium (II) tetra- fluoroborate (RuBMBP) was synthesized using 200 mg (0.683 mmol) of [Ril(‘1\1[~13)5C1][Cl]2 and 452 mg (3.3 mmol) of 3-methyl-l-(4-pyridy1)bu- tanone; crule yield of deep purple solid - 330 mg (93%) . Outplex for photolysis studies was recrystallized twice from water/ethanol , UV(wa- 1 1cm'1) 218 nm (e: 7000 ii om’1); IR(KBr) 3250-3350, 1672, 1590, 1300, 1200, 1025-1075 cm'1. ter) 506 nm (e 9820 m" cn'1) 266 nm (e 3350 m‘ M-l Pentaammine [4-methy1-l- (4-pyridyluaentanane] ruthenium (II) tetra- fluoroborate (Ruybb4VP) was synthesized using 200 mg (0.683 mmol) of ‘Ifiam3)sc,1] [C112 and 370 mg (2.1 mmol) of 4-methyl-l-(4-pyridyl) -.,. 'f’ 145 pentanone; crude yield of deep purple solid - 336 mg (97%) . Carplex for photolysis studies was recrystallized from water/ ethanol , UV (water) 519 nm (e: 9970 M'1cn'1) , 267 nm (3020 M’1cn’1) 222 nm (e 5560 M’1cu’1); UV(acetonitrile) 505 nm (e 9220 M'1cn'1) 265 nm (e 3690 M’1 cn’1) 221 nm (10440 m'1cn‘1); IR(KBr) 3150—3350, 1660, 1400-1450, 1000-1200, 800 cm71. Pentaammine [1— (4-pyridy1) pentanone] ruthenium (II) hexafluoro- m was synthesized by Meyer's method.197 Muopentaammineruthe— nium(II) hexafluorophosphate monohydrate [Ru(NH3)5H20] [(PF6)2°H20]: A stirred mixture of 20 ml 0.1 M sulfuric acid and several pieces of zinc mercury amalgam was deaerated for 20 min. Chloropentaammineru— thenium(II) dichloride (280 mg, 0.96 mmol) was added; after one hour a yellow-orange solution resulted, which was transferred to a 100 ml round battered flask. Saturated ammonium hexafluorophosphate (5 ml) was added and the solutian was refrigerated 12 hr. Filtration gave. a yellow solid which waswwashed with 3 ml of cold water (3—4°C) , then with anhydrous ether and stored in a vacuum dessicator at 3-40C; yield 150 mg (31%). PextaammineI1-(4-flridyl)pentanore]nrthenium(ll) hexa- fluorognogzbate: [R11(M«I3)5(H2))][(PF6)32'H2)] (119 mg, 0.23 mmol) was dearaeted in a 50 m1 Erlenmeyer flask fitted with a serum cap. A second flask containing 1- (4-pyridy1)pentanane (l g, 6.1 mmol) was also deaerated. Five m1 of acetone was added to each flask, the acetone solution of [Ru(NH3)5(HzO)]2+ was slowly added to the pyridyl ketone solution and stirred for 15 min. The solutim was added drop— wise to 100 ml of.anhydrous ether being bubbled with argan. The resultant precipitate was immediately filtered and washed twice with 30 m1 of anhydrous ether; yield 96 mg (64%); UV(water) 521 nm (e 4500 146 1 M“ cm-l) , 273 nm (e 2375 M'1cm'1) 223 nm (e 7060 M'1cn’1). Rhenium Campleces All complexes were prepared by a modification of the procedure reported by Wrighton et. a1.60 BrRe(CO) 5 was obtained from Pressure Chemical Carpany, pyridyl ketones were greater than 99.5% pure. fac-Tricarbonylbmmbis(pyridine)rhenium(1) (Repy) : BrRe(CO)S (200 mg, 0.492 mmol) and pyridine (97 mg, 1.2 m01) were dissolved in 250 ml of benzene. The colorless solution was heated at 80°C with stirringinthedarkunderargonforSh. Rerovalofthebenzeneunder reduced pressure left a white solid which was dissolved in 15 ml of methylene chloride. The addition of n—pentane precipitated the pro-‘- duct which was filtered and washed with g-pentane (2x5 ml). Recry- stallization twice fram methylene chloride and n—pentane gave a white solid; yield - 111 mg (45%); IR(CHZClZ) 2940, 2025, 1920, 1885 om'1; 1 1cut-l); m/e UV(benzene) 300 nm(sh) (e 8620 14" cm’1) 227 nm (e 10070 M' (rel int) chemical ionization 80(100) , electran impact 79 (100) . fac-Tricarbonylbrmobis (2—acety1pyridine) rhenium(I) (ReZAP) : BrRe(CO)5 (204 mg, 0.51 mmOl) and 2-acetylpyridine (122 mg, 1.1 mmol) were dissolved in 250 ml of benzene. The initially colorless solution vasheatedatBOOCinthedarkunderargonforGhr. Renovalofthe benzene under reduced pressure frum the now burgundy colored solution left an orange-red solid which was dissolved in 15 ml of methylene chloride. g-Pentane was added to give a cloudy solution which was refrigerated for 12 hr. An orange-red solid was filtered and washed with g-pentane (2x5 ml). Recrystallizatian twice from methylene chloride and n-pentane gave an orange-red solid; yield 211 mg (71%); 147 IR(CHZClZ) 2940, 2030, 1930, 1620, 1595-1575 (br) cm-l; IR(KBr) 2010, 1910—1890, 1610, 1585 cm’1; UV(benzene) 408 nm (e 4160 M'1cm’1) 277 nm (a 13140 m’1cn’1) . fac-Tricarbonylbrumobis (3—acetylpyridine) rhenium (I) (Re3AP) : BrRe(CO)5 (207 mg, 0.51 mmol) and 3—acety1pyridine (124 mg, 1.0 mmol) were dissolved in 250 ml of benzene. The colorless solution was stirredandheatedat 80°Cinthedarkunderargonfor6hr. Removal of the benzene under reduced pressure gave an off-white solid which was dissolved in 15 ml of methylene chloride. n—Pentane was added to give a cloudy solution which was refrigerated for 8 days until the oil solidified. The tan precipitate was filtered and washed with n—penv- tane (2x5 ml); yield - 262 mg (85%) . Recrystallization twice from methylene chloride and _Il-pentane gave a white solid; IR(CHZC12) 2030, 1930, 1890, 1690-1700(br) cn’1 1cm'1) ; UV(benzene) 300 nm(sh) (s 8290 M’ 277 nm (c 10900 M’1 '1) . fac-Jrricarbenylbrumobis (4-acetylpyridine) rhenium (I) (Re4AP) : BrReKD)5 (200 mg, 0.49 mmol) and 4-acetylpyridine (135 mg, 1.1 mmol) were dissolved in 250 ml of benzene. The initially colorless solution was stirredandreatedinthedarkmderargonat80°Cfor5h. Re- moval of the benzene under reduced pressure from tre now yellow solu- tion left a yellow solid which was dissolved in 15 ml of methylene chloride . Addition of _n-pentane precipitated a yellow solid which was filtered and washed with n—pentane (2x5 ml); yield - 184 mg (63%); IR 1 1 (CI-IZCIZ) 2030, 1930, 1890, 1690 an“ ; UV(benzene) 345 nm (e 8230 14" cn'l) 277 nm (e 9180 M‘1cn'1). fac-Tricarbonylbramobis [1- (2—pyridy1)butanone] rhenium (I) (ReZBP) : 13rme(c10)5 (200 mg, 0.50 mmol) and 1-(2-pyridy1)hutanme (147 mg, 0.99 148 mmol) were dissolved in 250 m1 of benzene. The initially colorless solutionwas stirredandheated at 80°C inthedarkunderargonfor 11hr. Rerovalofthebenzeneunderreducedpressurefremthenow burgundy colored solution left a red-orange solid which was dissolved in 15 ml of methylene chloride. _rn-Pentane was added to give a cloudy solution which was refrigerated for 24 hr. The red-orange solid was filtered, washed with _n-pentane (2:5 ml) and recrystallized twice from methylene chloride and n—pentane; yield - 180 mg (56%); IR(CHZClZ) ‘> 1 1 cm-l) 2950, 2030, 1930, 1900, 1710 cm- ; UV(benzene) 465 nm (e 3100 M- 1 277 nm (e 9700 M’ cm'1) . fac-Tricarbonylbremobis [1— (3-pyridy1) butanone] rlnenium (I) (Re3BP) : BrRe(CO)5(200 mg, 0.49 mmol) and 1-(3-pyridyl)butanone (190 mg, 1.3 ml) were dissolved in 250 ml of benzene. The initially colorless solution was heated at 70°C in the dark under argon for 11 hr. Removal of the benzene under reduced pressure from the now yellow solution left a yellow oil which was dissolved in 20 ml of methylene chloride. _n-Pentane was added to clouiiness , the solution was refrigerated exitlneoilwhichfomeddidmtsolidifyoveraperiodof 3weeks. The solvents were retoved under reduced pressure, 3 ml of methylene chloride was added and the solution was added dropwise to n—pentane . An off-white solid formed which was filtered, washed with n—pentane and recrystallized twice from methylene chloride and n—pentane; yield - 296 mg (95%); IR(CH2C12) 2950, 2025, 1930, 1895, 1695, 1595 cm'1; lam-1) . UV(benzene) 305 nm(sh) (e 2760 14' fac-T'ricarbonylbrurobis [1— (4—pyridyl) butanone] rhenium (I) (Re43P) : BrRe(CO)5 (198 mg, 0.49 mimol) and l-(4-pyridyl)butanone (133 mg, 0.90 mmol) were dissolved in 250 ml of benzene. The initially colorless 149 solution was stirred and heated at 70°C in the dark under argon until the evolution of carbon monoxide ceased. Removal of the benzene under reduced pressure from the now yellow colored solution left a yellow oil which was dissolved in 20 ml of methylene chloride . n—Pentane was added to give a cloudy solution which was refrigerated for 20 d. The oil which formed did not solidify. The solvents were removed under reduced pressure , the oil was dissolved in 3 ml of methylene chloride , added drOpwise to 250 ml of g-pentane and refrigerated for 2 days. A yellow solid formed which was filtered and washed wirh n_—pentane and then recrystallized from methylene chloride and _n-pentane; yield - 67 mg (20%); IR(CHZClz) 2940, 2040, 1940, 1900, 1700 om'1; UV(benzene) l 337 nm (e 3100 M’ (rm-1). fac-Tricarbonylbratobis [1- (ijridLl) pentanone] rhenium (I) (ReZVP) : BrRe(CO)5 (204 mg, 0.50 mmol) and l-(2-pyridyl)pentanone (164 mg, 1.0 mmol) were dissolved in 250 ml of benzene. The initially colorless solution was stirred and heated at 80°C in the dark under argon for 6 h. Reroval of the benzene under reduced pressure left a red solid which was dissolved in 20 ml of methylene chloride. n-Pentane was added to give a cloudy solution which was refrigerated for 2 days . A red solid formed which was filtered arnd washed with _r_n_—pentane (2:5 ml) arnd then recrystallized twice from methylene chloride and _rn—pentane ; yield - 195 mg (58%); IR(KBr) 2010, 1995, 1605, 1595 cm-l; IR(CHZClz) 2030, 1 1 1930, 1890, 1620, 1595 cm“ ; UV(benzene) 468 nm (e 2270 M’ an’1) 277 1om’1); ms CI m/e 434(3.6) , 164 (100); 131 m/e 514(2.2) , nm (e 8230 M‘ 44(100) . fac-Tricarbonylbrtmobis [1— (3-pyridy1)pentanone] rhenium (I) (Re3VP) : BrRe(CO)5 (199 mg, 0.49 mmol) and 1-(3-pyridyl)pentanane (168 mg, 1.03 150 mmol) were dissolved in 250 ml of. benzene. The initially colorless solution was stirred and heated at 80°C in the dark under argon for 5 h. Removal of the benzene under reduced pressure from the now yellow solution left a yellow solid which was dissolved in 20 ml of methylene chloride . E-Pentane was added to give a cloudy solution which was refrigerated for 14 d. The oil which formed did not solidify. The solvents were removed under reduced pressure . The yellow solid was dissolved in 20 ml of methylene Chloride , n—pentane was added to cloudiness and the solution was refrigerated for 10 d. A white solid formed which was filtered, washed with n—pentane (2:5 ml) and recry- stallized twice from methylene chloride and g-pentane ; yield - 296 mg (89%); IR(KBr) 2050, 1930-1890, 1700 cm'1 1 ; IR(CHZC12) 2030, 1930, 1890, 1 1700, 1620, 1590 cm- ; UV(benzene) 300 nm(sh) (c 10500 M. (In-1) 277 nm 1om'1); ms CI m/e 204(2.8) , 192(10.6) , 164 (100); EI m/e (s 13400 M‘ 163(4.1), 106(100). fac-Tricarbonfibromobis [1- (4jayridyl) pentanone] rhenium (I) (Re4VP) : BrRe(CO)5 (199 mg, 0.49 mmol) and 1-(4-pyridyl)pentanone (191 mg, 1.2 mmol) were dissolved in 250 ml of benzene. The initially colorless solution was stirred and heated at 80°C in the dark under argon for 5 h. Removal of the benzene from the yellow solution left a yellow oil which solidified on the addition of Ln-pentane. The yellow solid was filtered, washed with n—pentane (2:5 ml) and recrystallized form methy- lene chloride arnd _n-pentane; yield - 267 mg (81%); IR(CHZClZ) 2950, 1 1 2030, 1925, 1890, 1685, 1260 cm’ : UV(benzene) 344 nm (a 10270 M'1cn’ 1om’1); ms CI m/e 192(15.3) , 164 (100); BI m/e 163 ) 277 nm (a 10320 M' (15.8), 121 (100). fac-Tricarbonylbrombis (3-benzoylpyridine) rhenium(I) : BrRe (CO) 5 151 (202 mg, 0.50 mmol) and 3-benzoy1pyridine (184 mg, 1.0 mmol) were dissolved in 250 ml of benzene. The initially colorless solution was heated at 70°C in the dark under argon at 70°C for 7 hr. Reroval of the benzene under reduced pressure from the cloudy yellow solution left a yellow oil which was dissolved in 20 ml of methylene chloride. _n-Pentane was added to cloudiness and the solution was refrigerated for 14 d. The yellow oil which formed did not solidify. The solvents were reroved under reduced pressure . The yellow solid was dissolved in 15 ml of methylene chloride , _n-pentane was added to cloudiness and the solution was refrigerated for 12 h. A white solid formed which was filtered, washed with n—pentane (2:5 ml) and recrystallized twice from methylene chloride and g-pentane; yield - 266 mg (75%); IR(CHZCl l 2) ; UV (benzene) no peaks before solvent cut- 1cm’1; ms 12:1 m/e 184 (100); CI m/e 183 2025, 1925, 1890, 1670 cm’ offuat 275 mm; = 5810 M” 8313 nm (60), 105(100). MethodsandTechnicmes Preparation of Samples Photochemical Glassware: Class A pipets, Class A volumetric ware and pyrex syringes with chrote plated brass needles were used to pre- pare sample solutions for photolysis. All glassware was cleared by rinsing with acetoe, then distilled water, followed by l'eating in a distilled water solution of Alconox laboratory glassware detergent for aminimumof 24 hoursandthenleatingtwotimes foraminimumof 10 hours with fresh samples of distilled water. All glassware was dried at 140°C in an oven used only for photochemical glassware to avoid any 152 Irradiation Tubes: Photolysis tries (13 x 100 mm Pyre: culture tubes) were cleaned in a manner analogous to the photochemical glass- ware. The necks were drawn out to the desired length by rotation in an oxygen flame. Stock Solutions arnd Photolysis solutions: A Sartorious Model 2403 balance (accurate to i 0.001) was used to weigh the desired amount of substrate into a volunetric flask which was then diluted to volute with the appropriate solvent . Solutions were used directly or by pipetting an appropriate aliqout into another volunetric flask and diluting to volune. Degassing Procedure: A 5 ml syringe was used to fill tre irra- diation tubes with 2.8 ml of the appropriate solution. T‘l'e tubes were attached to a vacuum line on a manifold fitted with 12 stopcocks using one hole rubber stOppers (size 00). All samples were'degassed by four freeze-pump—thaw cycles; frozen by slow immersion into tre liquid nitrogen, putped for 10-20 minutes at 5 x 10'4 m, then allowed to thaw by starnding in air. On tl'e final cycle, the tunes were frozen, then pumped and sealed with an oxygen torch under vacuum. Irradiation Procedures : Photochemical studies involved the use of three different irradiation apparati. Two of these involved tre use of Hanovia 450 watt medium pressure mercury lamps cooled by quartz immersion wells which were placed inside a “merry-go-round" apparatus (7 mm slit width) .199 T‘l'e entire apparatus was placed inside alarge crock filled with distilled water held at 25°C. All tubes were irra- diated in parallel to ensure that each received an equal amount of liglnt. Tb isolate tlre 313 nm region, an aqneous filter solution of 0.002 M potassium chrcmate and 1% potassium carbonate was used. To 153 isolate the 366 nm region, a Corning No. 7—83 filter was employed. TrethirdapparatuswasanOpticalbench-alOOOwattXenonlampin linewithaBauscharxiLombmonochrometerheldBomfrumtl'equartz window of an ambient tenperature lamp containing a merry-go-round apparatus. Analysis of Samples Identification of Photoproducts: T‘Ie alkyl pyridyl ketones were identified by cotparison with the gas chromatography (go) retention times of authentic samples . The alkene photoprodncts of tie penta- ammnineruthenium (II) pyridyl ketone conplexes were identified by comparison with the go retention time of alkene generated by inde- pendent photolysis of the free pyridyl ketones (Peak #1 = alkene, Peak #2 = cyclohe:ane) . Other photoproducts were identified by isolation #1 A #2 acetonitrile J Li/ and conparison with authentic samples . Ligand Fragmentation : Ligands were identified by cotparison of the go retention time with an autlentic sample. 154 Gas Chroratographyi‘Procedures: (kn-column sample injections of 0.4 microliters were mnade into 1/8 inch diameter aluminum columns using nitrogen as the carrier gas . The following columns were enployed: Column A - 5% (JP-1, 1.25% Carbowax 20M, Chromosorb G 60:80 DMSC acid washed, treated with Me35iNHSiMe3; 25 ml/min (N2 flow rate); 8' x 1/8"; 50°C column, 150°C injector, 200°C detector (propene analysis); 140°C column, 170°C injector, 200°C detector (acetophenone anaylsis). Column B — 5% (JP-1, 1.25% Carbowax 20M, 2% potassium hydroxide, Chrotosorb G 60:80 116C acid wasted, treated with 1e3SiNHSiMe 25 3, ml/min (N2 flow rate); 12' x 1/8"; Column tenperature varied with analysis (see Appendix), 180°C injector, 200°C detector (pyridyl ketone analysis). Column C - 25% l,2,3-tris(2-cyanoethoxy)propane, Chronosorb W 1145C acid wasted; 25' x 1/8"; 25 ml/min (N2 flow rate); 50°C column, 40°C injector, (gi_s_- and _trins_-1,3-pentadiene analysis). Column D - 20% SIS-30, Chrotosorb W 60:80 116C acid wasted; 25 ml/min (N2 flov rate); 5' x 1/8"; 235°C column, 245°C injector, 250°C detector (glg- and Eng-stilbene analysis). Column E - 5% 8151-30, Chronosorb W 60:80 [NSC acid wasted; 25 ml/min (N2 flow rate); 5' x 1/8"; 125°C column, 180°C injector, 200°C detector (bibenzyl analysis); 170°C column, 180°C injector, 200°C detector (1 ,2—di-p—toylyethane and 2 ,3-diphenyl—2 ,3-butanediol analy- sis). Column F - 20% Carbowax 20M, Chronosorb G 60:80 11432 acid wasted; 25 ml/min (N2 flow rate); 8' x l/8"; 60°C column, 80°C injector, 200°C detector (acetone anaylsis) . 155 Actinometry and quantum Yield Determination Internal standards were used for all analyses except for tie photoreduction studio and Type II disappearance studies in acetoni— trile ere the standard was added after photolysis. Tl'e concentra- tion of photoproduct has determined using the go area product : inter- nal (external) standard area ratio. A detector response factor (RF) was determined to account for the difference in molar response for each conpound. The response factor is the reciprocal lepe of the plot of concentration ratio of compound to standard versus area ratio of compound to standard. Response factors are listed in Table 31. Product concentrations were determined from (49) . [Product] = RF x [Internal x Area of Product (49) Standard] Area of Internal Standard ValerOphenone actinotetry was used for all product quantum yield determinations. A 0.1 M solution of valemphenone in benzene contain- ing a loom concentration of cyclohexane and/or hexadecane was irra- diated with the desired corpound and analyzed on Column A. PhotOpro- duct quantum yields were determined from (50) . The quantum yield for 0.1 M valerophenone in benzene is 0.33 [Product] = X 0.33 (50) [Product] actinoreter q’Product When tie ketore did not absorb all the light, an absorbarnce correction was made by multlplylng up rod uct by the followrng equation based on Beer's Law: _ 1 — Tactinometer 1 - Tketone Absorbance Correction (51) 156 Table 31. Internal Standard : ketone response factors . Internal Standard : Ketone if; hexadecare : acetOphenone (AP) 2.20 octadecane : acetOphenone (AP) 2 . 4 0 pentadecane : 1,2-di-p—tolylethane (DT‘E) 0.95 hexadecane : 2—acetylpyridine (ZAP) 2 . 94 heptadecane : 2—acetylpyridine (ZAP) 3 . 36 heptadecane : 3-acetylpyridine (3AP) 3 . 66 heptadecane : 4—acetylpyridine (4AP) 3 . 06 octadecane : 4-acetylpyridine (4AP) 3.09 octadecane : 2-butyrylpyridine (ZBP) 2.37 nonadecane : 2-butyrylpyridine (ZBP) 2 . 67 heptadecane : 3-butyrylpyridine (3BP) 2 . 55 eicosane : 3-butyrylpyridine (3BP) 2. 76 heptadecane : 4-butyrylpyridine (4BP) 2.50 heptadecane : 2-valerylpyridine (2VP) 2.19 eicosane : 2-va1erylpyridine (2VP) 2.26 heptadecare : 3-valerylpyridine (M) 2.21 nonadecare : 3-valerylpyridire (3VP) 2.24 heptadecane : 4-valerylpyridine (4VP) 2. 74 heneicosane : 4-valery1pyridine (4VP) 2 .62 heptadecane : 3-methy1-3—butyrylpyridine (BNE3BP) 2.52 Ieptadecane : 3-methyl—4-valerylpyridine (MVP) 2 . 26 octadecane : gang-stilbene 1.40 cyclohexane : propene (assured) 2.00 cyclokexane : 2—methylpropene (assumed) 1.50 cyclorexane : acetone 3 . 01 Ketone disappearance quantum yields (<1>_K) were determined by two methods. When the internal(external) response factor was lcnown, tie quantum yields were calculated by the usual method. When tie internal (external) response factor was not knom, disappearance quantum yields 157 were determined by cotparing the ketone : internal (external) standard area ratios of the solutions before and after irradiation. The factor R (52) , when multiplied by the original ketone concentration and the result subtracted from the original ketone concentration, gives the change in ketone concentration (53) from which tre disappearance quan- tum yield is calculated (54) . (Area'Ketone ) Area after Standard _ / (AreaKetone )bef — R (52) ore AreaStandard [Kemdoriginal - R[Ketcne] original = A[Ketone] (53) <1>_K =Ii°£mi x 0.33 - (54) [mm1actirmeter mximum Type II fragmentation quantum yields (9m) : A constant aliquot of stock ketone solution was pipetted into several voluretric flasks . Varying alliquots of stock _tfi-butyl alcohol were added to give concentrations from 1.0-8.0 M after dilution. The tubes were prepared, irradiated and analyzed in the usual manner. Type 11 quantum yields extrapolated to infinite dilution (9:) : Varying aliquots of stock ketone were pipetted into volutetric flasks to give concentrations up to 0.15 M after dilution. Tie tubes were prepared, irradiated in two sets to assure conparable percent conver- sion over tire concentration range and analyzed in the usual manner. The y-axis intercept of the plot of 4’11 versus [Ketone] is 4:. Photoreduction quantum yields were determined by the irradiation of a constant aliquot of stock ketone solution in the presence of various hydrogen donors . The absoluted quantum yield of photOproduct 158 fonmation were determined by adding various aliquots of stock donor solution to a constant aliquot of stock ketone solution arnd diluting to volure. Tre tubes were prepared, irradiated and analyzed in the )-1 yields a line in which the lepe divided by the intercept equals k d/kr. usual manner. A plot of (ma versus [hydrogen donor] -1 cetOphenone Intersystem crossing yields were determined from the ketone sensi- tization of the gig-fl isonerization of either gi_s-l,3-pentadiene or fl-stilbee. A constant aliquot of stock ketone solution was pipetted into several voluretric flasks. Varying aliquots of stock quencher solution were also pipettted into the flasks and diluted to volure. Actinometers were prepared by making a solution of the appro- priate ketone (acetoplnenone for 313 nm, benzOphenone for 366 mm) and adding enough quencher solution to quench more than 99% of the triplet state. Tubes were prepared, degassed , irradiated and analyzed in tie usual manner. Results were analyzed using (55)-(57) . For g_i_s_-l,3-pen— Area . B = new war (55) Area new isoner Area original isorer B' = ln ‘1 (56) a + B e' x [masher] q) _ = 'keme X 0. (57) isom 8 actinoneter x [Quencher] tadiene, a = 0.55, for trans-stilbene, c = 0.596.198 A plot of a/ versus [Quencher] '1 yields a line in which the reciprocal of isom the intercept equals ¢isc and the intercept divided by the slope equals qu. r y‘— 159 Stern Volmer Studies For the Norrish Type II fragmentation studies , samples of ketone solution were prepared in the same manner as for the intersystem crossing studies . For tie intermolecular photoreduction studies , the samples of ketone solution contained in addition a constant aliquot of hydrogen donor. The slope of d>o/d> versus [Quencher] gave kqn. Absqation Spectra Spectra were taken using 10 mm matcred quartz cells. A Beckmen recording quartz spectrophotoneter with Gilford accessories was used to determine the extinction coefficients at 313 and 366 nm. T‘l'e I spectra of tie ruthenium complexes were taken immediately after the solutions were made. Extinction coefficients are reproduceable to r 10% . Emission _Spectra Spectra were taken using 5 mm quartz tubes at room terperature, or at 770K using a quartz dewar for liquid nitrogen. Ketone solution concentrations were approximately 1. 5 x 10.4 M, rhenium pyridyl ketone 4 M. The chopper was used at high speed, to assure that only the long lived corponent of conplex solutions were approximately 2. 5 x 10- emission was seen (greater than 50 nsec) . LIST OF RE'FEREI‘CES 10. 11. 12. 13. 14. 15. 16. 17. LIST OF REFERENCES V. Balzani and V. Carassiti, "Photochemistry of Coordination Conpounds", Academic Press, London, 1970, Chapter 5. J. Bjerrum, A. W. Anderson and O. Bostrup, Acta. Chem. Scand. 10, 329 (1956). K. Nakamaro, K. Hin, A. Tazawa and M. Kanno, Bull. Chem. Soc. JE-p 48, 3486 (1975). F. A. Cotton and G. Wilkinson, "Advanced Inorganic Chemistry" , John Wiley and Sons, Inc., 1972, p. 618. A. W. Adamson, Pure and Appl. Chem, 51, 313 (1979) . G. A. Crosby, U. S. Govt. Res. Develop. Rep” 1968, 6_8_(6), 58 J. Endicctt, Survey of Progress in Inoganic Chemistry, 1, 41 (1967). A. W. Adamson, W. I. Waltz, E. Zinato, D. W. Watts, P. D. Fleischaner and R. D. Lindholnn, Chem. Rev., 6_8_, 541 (1968). P. D. Fleischauer and P. Fleischauer, Chem. Rev., _7__Q, 199 (1971) . V. Balzani arnd V. Carassiti, "Photochemistry of Coordination Conpounds", Academic Press, London, 1970. M. S. Wrighton, ed., Adv. Chem. Ser., 18___4, 1978 (interfacial PhotOprocesses: Energy Consenvation and— Synthesis). P. J. DeLaive, D. G. WhittenandC. Giannotti,Adv. Chem. Ser. 17__§_, 236-251 (1978). B. S. Hall and K. F. Dahnke, J. Phys. Chem, 8);, 866 (1977). M. Z. Hoffman and K. R. Olsen, J. Phys. Chem, 83, 2631 (1978). P-Yu Manvilov and G. A. Shagisultanova, Zh. Neorg. Khim., 23, 1856 (1978) . K. R. Ieopold and A. Haim, Inorg. Chem, _1_7_, 1753 (1978). E. Finkerberg, P. Fischer arnd S-My Haung, J. Phys Chem, 8_2, 526 (1978). 160 161 18. S. F. Bergson and R. J. Watts, J. Amer. Chem. Soc., 101, 3151 (1979). 19. E. J. Watts, J. S. Harrington and J. Van Houten, Adv. Chem. Ser., 168, 57 (1978). 20. G. Ferraudi, _Iggrg. Chem, 18, 1576 (1979). 21. M. Talebinasab—Sarvini, A. W. Zanella and P. C. Ford, Inorg Chem, 18, 1835 (1980); A. W. Zanella, M. Talebinasab—Sarvini and P. C. Ford, Inorg. Chem, _1_5_, 1980 (1976). 22. T. Marsubara, M. Bergkamp and P. C. Ford, Inorg. Chem, _11, 1604 (1978). 23. A. V. loginov, V. A. Yakovlev and G. A. Shagisultanova, Koord. Khim., _5_, 733 (1979). 24. J. D. Petersen, R. J. Watts and P. C. Ford, J. Amer. Chem. Soc., 88, 3189 (1976). 25. M. A. Bergkamp, J. Brannon, D. Madge, R. J. Watts and P. C. Ford, J. Amer. Chem. Soc., 101, 4549 (1979). 26. 1. A. Bergkamp, R. J. Watts and P. C. Ford, J. Amer. Chem. Soc., 102, 2627 (1980). 27. J..D. Petersen and P. C. Ford, J. Phys. Chem, 28, 1166 (1974). 28. R. C. Young, J. K. Nagle, T. J. Meyer and D. G. Whitten, J. Amer. Chem. Soc., 100, 4773 (1978). 29. J. K. Hurst, Biochemistry, 18, 1504 (1979). 30. J. P. Paris and W. W. Brandt, J. Amer. Chem. Soc., 8_1_, 5001 (1959). 31. 101. I. Mamedov and R. Z. Laipanov, Zh. Prikl. Spektrosk, _7_, 49 (1967), Chem. Abstr., 88, 100349t (1968). 32. J. N. Demas and G. A. Crosby, J. Amer. Chem. Soc., _9_2, 7262 (1970). 33. F. E. Lytle and D. M. Hercules, J. Amer. Chem. Soc., _98, 253 (1969). 34. R. H. Fabian, D.M. Klassen and R. W. Sonntag, Inorg. Chem, 18, 1977 (1980) and references therein. 35. J. N. Demas and G. A. Crosby, J. Mol. Spectrosc., 29.: 72 (1968); J. N. Demas and A. W. Adamson, J. Amer. Chem. Soc., 88, 1800 (1971). 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 162 J. N. Demos and G. A. Crosby, J. Amer. Chem. Soc., 83_, 2841 (1971). W. M. Wallace and P. E. Hoggard, Inorg. Chem, 18, 2141 (1980) . J. Van Holten and R. J. Watts, J. Amer. Chem. Soc., 88, 4853 (1976) . P. Natarajan and J. F. Endicott, J. Amer. Chem. Soc., 88, 5909 (1972). C. Sigwart and J. Spence, J. Amer. Chem. Soc., 81, 3991 (1969). P. C. Ford, D. H. Struermer and D. P. McDonald, J. Amer. Chem. _Sr_n_c_., 81, 6209 (1969). D. A. Chaisson, R. E. Hintze, D. H. Steurmer, J. D. Petersen, D. P. McDonald and P. C. Ford, J. Amer. Chem-Soc., 81, 6655. (1972). R. E. Hintze and P. C. Ford, Inorg. Chem, 81, 1211 (1975). P. C. Ford, D. A. Chaisson and D. H. 'Stuermer, Chem. Comm, 530 (1971) . p. C. Ford, Coord. Chem. Rev., 8, 75 (1970). P. C. Ford, J. R. Kuempel and H. Taube, Inorg. Chem, _7_, 1976 (1968). R. E. Hintze and P. C. Ford, J. Amer. Chem. Soc., 8_7_, 2664 (1975). P. C. Ford, J. D. Petersen and R. E. Hintze, Coord. Chem. Rev., 1_4_, 67 (1974). G. Malouf and P. C. Ford, J. Amer. Chem. Soc., 88, 7213 (1977). G. Manlouf and P. C. Ford, J. Amer. Chem Soc., 8_6_, 601 (1974). P. P. Zarnagar and D. G. Whitten, J. Amer. Chem. Soc., 83_, 3776 (1971). P. P. Zarnegar, C. R. Bock and D. G. Whitten, J. Amer. Chem. Soc., 85_, 4367 (1973). D. G. Whitten and M. T. MJCall, J. Amer. Clnem. Soc., 81, 5097 (1969). E. A. Koerner von Gustorf and F. W. Grevels, Fortschr. Chem. Forsch., 18, 366 (1969). 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 163 M. Wrighton, Chem. Rev., 111, 401 (1974) . M. S. Wrighton, H. B. Abrahamnson and D. L. Morse, J. Amer. @. Soc., 88, 4105 (1976). M. Wrighton, G. S. Hammond and H. B. Gray, J. Amer. Chem. Soc., 88, 4336 (1971). M. Wrighton, G. S. Hammond and H. B. Gray, Inorg. Chem, 11, 3122 (1972). M. Wrighton and D. L. Morse, J. Amer. Chem. Soc., 88, 998 (1974). M. S. Wrighton, D. L. Morse and L. Pdungsap, J. Amer. Chem. Soc., 8_7_, 2073 (1975). P. J. Giordano and M. S. Wrighton, J. Amer. Chem. Soc., 10_1_, 2888 (1979). P. J. Giordano, S. M. Fredricks, M. S. Wrighton and D. L. Morse, J. Amer. Chem. Soc., 100, 2257 (1978). S. M. Fredricks, J. C. Loung and M. S. Wrighton, J. Amer. Chem. Soc., 101, 7145 (1979). R. G. W. Norrish, Trans. Faradgy Soc., _38, 1521 (1937). N. J. Turro, "Nbdern Molecular Photochemistry", Benjamin Cummins Publishing Conpany, Menlo Park, Calif., 1978, p.182. M. A. El-Sayed, Accts., 1, 8 (1968); A. A. Lamola and G. S. Hammond, J. Chem. Phys., E, 2129 (1965). P. J. Wagner, Accounts Chem. Res., _4_, 168 (1971). D. R. Coulson and N. C. Yang, J. Amer. Chem. Soc., 88, 4511 (1966). P. J. Wagner and G. 8. Hammond, J. Amer. Chem. Soc., _88, 1245 (1966); W. D. Clark, A. D. Litt and C. Steel, J. Amer. Chem. Soc., 91, 5413 (1969); G. Porter and M. R. TOpp, Proc. Ro_y. Soc., Ser. A, 315, 163 (1970). P. J. Wagner and G. S. Hammond, J. Amer. Chem. Soc., 82, 4009 (1965). P. J. Wagner, J. Amer. Chem. Soc., 88, 5898 (1967). N. C. Yang and D. H. Yang, J. Amer. Chem. Soc., 88, 6672 (1970). P. J. Wagner, P. A. Kelso, A. E. Kerppainen, J. M. McGrath, H. N. Schott and R. G. Zepp, J. Amer. Chem. Soc., 841, 7506 (1972). 74. 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87. 88. 89. 90. 164 'P. J. Wagner, P. A. Kelso and R. G. Zepp, J. Amer. Chem. Soc., 88, 7480 (1972). F. D. Lewis, J. Amer. Chem. Soc., 8_2_, 5602 (1970). C. Walling arnd M. J. Gibian,'J. Amer. Clnem. Soc., 8_7, 3361 (1965); A. Padwa, Tet. Lett., 3465 (1964). P. J. Wagner and R. G. Zepp, J. Amer. Chem. Soc., 34, 287 (1972). . A. A. Lamola, J. Chem. Phys., :11, 4810 (1967). P. J. Wagner and G. S. Hammond, Adv. Photochem, _5_, 94 (1968); H. L. J. Backstrom and K. Sandros, J. Chem. Phys., _2_3_, 2197 (1955); S. P. McGlynn, "Molecular Spectrosc0py of the Triplet State", Prentice Hall, Englewood Cliffs, N. J., 1969, Chap. 4 arnd 6. P. J. Wagner and G. 8. Hammond, Advan. Photochem, 8, 21 (1968); D. R. Arnold, R. L. Hirnman and A. H. Glick, Tetrahedron Lett., 1425 (1964); W. Bergmark, B. Beckman and W. Lindenberger, Tetrahedron Lett., 2259 (1971). J. N. Murrell, "The Theory of the Electronic Spectra of Organic Nblecules", Methun and Co., Ltd., 1963, p. 206, 227; S. Nagakura and J. Tarnaca, J. Chem. Phys., 88, 236 (1954). D. Bryce-Smith, Pure Appl. Chem, 18, 47 (1968). P. J. Wagner, I. E. Kochevar and A. E. Kemppainen, J. Amer. Chem. Soc., 9_5_, 5604 (1973). P. J. Wagner, I. E. Kochevar and A. E. Kemppainen, J. Amer;._ Chem. Soc., 84_, 7506 (1972). J. Petruska, J. Chem. Phys., 2, 1120 (1961); N. C. Yang, D. S. McClure, S. L. Murov, J. J. Houser and R. Dusenbery, 8; Amer. Chem. Soc., 88, 5466 (1967); N. C. Yang and R. Dusenberg, Mol. Photochem, 1, 159 (1969). P.J. Wagner and A. E. Kemppainen, J. Amer. Chem Soc., 841, 7456 (1972). . W. A. Prior, "Free Radicals", McGraw Hill, New York, 1966, p. 154. G. Ciamician and p. Silber, B__e_r._, 231: 2911 (1900); 3.5, 1530 (1901). A. Schonberg and A. Mustafa, Chem. Rev., 48, 181 (1947). J. C. Scaiano, Mol. Photochem, _2_, 81 (1973/43). 91. 92. 93. 94. 95. 96. 97. 98. 99. 100. 101 . 102. 103. 104 . 165 E. Paterno and G. Chieffi, Gazz. Chem. Ita1., 88, 11, 415 (1909); 88, _1_1, 321 (1910). R. S. Davidson and P. F. Iambeth, J. C. S. Chem. Comm, 1265 (1967); S. G. Cohen and H. M. Chao, J. Amer. Chem. Soc., 88, 165 (1968); A, Padwa and W. Eisenhardt, J. Amer. Chem. Soc., 88, 1400 (1971); S. G. Cohen and N. M. Stein, J. Amer. Chem. Soc., 88, 6542 (1971); S. G. Cohen and J. B. Guttenplan, J. Amer. Chem. Soc., 8_4, 4040 (1972); S. G. Cohen, A. Parole and G. H. Parsons, Chem Rev. , 73,141 (1973); S. Inbur, H. Linshitz and S. G. Cohen, J. Amer. Chem. Soc., 102, 1419 (1980). P. J. Wagner, J. Amer. Chem. Soc., _88, 2503 (1967). G. Ciamician and P. Wilber, Chem Ber., 84_, 1554 (1911); S. G. Cohen and S. Aktipis, J. Amer. Chem. Soc., jg, 3587 (1966). S. G. Cohen and J. B. Guttenplan, J. Amer. Chem. Soc., 84_, 4040 (1972); J. B. Guttenplan and S. G. Cohen, J. Chem. Soc. Chem. Comm, 247 (1969). J. B. Guttenplan and S. G. Cohen, J. Org. Chem, 38, 2001 (1973); S. G. Cohen, A. W. Rose, P. G. Stone and A. E‘hret, J. Amer. Chem. Soc., 101, 1827 (1979). H. D. Becker, J. Org. Chem, .312: 2116 (1967); 22: 2124 (1967); 8_2_, 2140 (1967). G. 8. Hammond, W. P. Baker and W. M. more, J. Amer. Chem. Soc., 88, 2795 (1961); G. S. Hammond and P. A. Leermakers, J. Amer. Chem. Soc., 88, 207 (1962). S. G. Cohen, D. A. Laufer and W. V. Sherman, J. Amer. Chem. Soc., 8_6_, 3060 (1964). M. Bodenstein, Z. Physik. Chem, B12, 151 (1931); H. L. T. Backstrom, Z. Physik. Chem, B25, 99 (1934); C. Weizmann, E. Bergmann and Y. Hirschberg, J. Amer. Chem. Soc. , 88, 1530 (1938). J. N. Pitts, Jr., R. L. Leisinger, R. D. Taylor, J. M. Patterson, G. Recktenwald and R. B. Martin, J. Amer. Chem. Soc., 81, 1068 (1959). J. N. Pitts, Jr., H. W. Johnson and T. Kuwana, J. Phys. Chem, 88, 2456 (1962) , A. Beckett and G. Porter, Trans. Faraday Soc., 88, 2039 (1963). H. J. L. Backstrom and K. Sandros, J. Chem. Phys., 88, 2197 (1955) . G. N. Lewis and M. Kasha, J. Amer. Chem. Soc., 88, 2100 (1944); G. N. Lewis and M. Calvin, J. Amer. Chem. Soc., 6_7_, 1232. (1945). 106 . 107. 108 . 109 . 110. 111. 112 . 113 . 114 . 115 . 116 . 117. 118. 119. 120. 121. 122 . 166 H. L. Backstrom and K. Sandros, Acta. Chem. Scand., _14, 48 (1960). G. Porter and R. Wilkinson, Trans. Faraday Soc., 8_6_, 1686 (1961); G. S. Hammond and P. A. Leermakers, J. Phys. Chem, 88, 1148 (1962); W. M. Nbore and M. Ketchum, J. Amer. Chem. Soc., 84_, 1368 (1962) . G. 8. Hammond, N. J. Turro and P. A. Leermakers, J. Amer. Chem. Soc., _8_3, 2396 (1961); J. Chem. Phys., 86, 1144 (1962). G. S. Hammond, W. P. Baker and W. M. Moore, J. Amer. Chem. Soc., 83_, 2795 (1961); G. S. Hammond and W. M. Nbore, J. Amer. Chem. Soc., 81, 6334 (1959); W. M. Nbore, G. 8. Hammond and R. P. Foss, J. Amer. Chem. Soc., 88, 2789 (1961). J. A. Bell and H. Linschnitz, J. Amer. Chem. Soc., 88, 528 (1963) . G. O. Schenck, M. Czkesla, K. Eppinger, G. Matthias and M. Pape, Tetrahedron Lett., 193 (1967) . G. O. Schenck and G. Matthias, Tetrahedron Lett., 669 (1967) . H. L. J. Backstrom, K. L. Appelgren and R. J. V. Niklassun, Acta. Chem. Scand., 19, 1955 (1965). P. J. Wagner and R. A. Leavitt, J. Amer. Chem. Soc., 8_2_, 5806 (1970). P. J. Wagner and R. A. Leavitt, J. Amer. Chem. Soc., _9_5_, 3669 (1973). R. A. Leavitt, M. S. Thesis, Michigan State University, 1969, p. 28. R. A. Leavitt, Ph.D. Thesis, Michigan State University, 1971, p. 28. . A. E. Puchalski, Ph.D. Thesis, Michigan State University, 1980. P. J. Wagner and G. Capen, Mol. Photochem, _1_, 173 (1969). M. R. Kegelmand and E. V. Brown, J. Amer. Chem. Soc., 18, 4649 (1953); W. L. Bencze and M. J. Allen, J. Amer. Chem. Soc., 81, 4015 (1959); W. L. Bencze, C. A. Burckhardt and W. L. Yost, J. Org. Chem, _2_1, 2865 (1962). D. A. Nelson and E. Hayon, J. Chem Phys., _78, 3200 (1972) . F. L. Minn, C. L. Trichillo, C. R. Hunt and N. Filipeseu, 8_._ Amer. Chem. Soc., 88, 3600 (1970). 167 123. P. J. Wagner, "Creation and Detection of the Excited State", Vol _1A_, A. A. Lamola, ed., Marcel Decker, New York, 1971, p. 173. 124. K. Sandros and H. J. L. Backstrom, Acta. Chem. Scand., _18, 956 (1962); W. G. Herkstroeter and G. L. Hammond, J. Amer. Chem. Soc., 88, 6534 (1966); P. J. Wagner and I. E. Kochevar, J. Amer. Chem. Soc., 88, 2232 (1968). 125. A. A. Lamola and G. S. Hammond, J. Chem. Phys., _4_8, 2129 (1965). 126. N. J. Turro, "molecular Photochemistry", W. A. Benjamin, Inc., Reading, 14155., 1965, p. 5. 127. A. W. Adamson and P. D. Fleischauer, "Concepts of Inorganic Photochemistry, John Wiley and Sons, Inc., 1975. 128. A. E. Kemppainen and P. J. Wagner, J. Chromatographic Sci., 18, 148 (1974) . 129. E. C. Alexander and R. J. Jackson, Jr., J. Amer. Chem. Soc., 88, 5663 (1974). 130. E. C. Alexander and R. J. Jackson, Jr., J. Amer. Chem. Soc., 88, 1609 (1976). 131. F. G. Moses, R. S. H. Liu and B. H. Monroe, Mal. Photochem, _1_, 245 (1969). 132. P. J. Wagner, 1. E. Kochevar and A. E. Kemppainen, J. Amer. Chem. Soc., 84, 7489 (1972). 133. D. R. Arnold, Adv in Photochem, _6_, 328 (1968). 134. M. L. May, Ph.D. Thesis, Michigan State University, 1977, p. 15. 135. P. Ford, D. F. P. Rudd, R. Gaunder and H. Taube, J. Amer. Chem. Soc., 88, 1187 (1968). 136. K. Schug and C. P. Guengerich, J. Amer. Chem. Soc., 101, 235 (1979). 137. A. Zanella and H. Taube, J. Amer. Chem. Soc., 88, 7166 (1971). 138. C. G. Kuehn and H. Taube, J. Amer. Chem. Soc., 88, 690 (1976). 139. F.D. Lewis and T. A. Hillard, J. Amer. Chem. Soc., 'g_2_, 6672 (1970). 140. P. J. Wagner and A. E. Kempainen, J. Amer. Chem. Soc., 88, 5896 (1968). 141 . 142. 143. 144 . 145. 146. 147. 148 . 149. 150. 151. 152. 153. 154 . 155 . 156 . 168 P. J. Wagner and I. E. Kochevar, J. Amer. Chem. Soc., fl), 2232 (1968). H. Paul, R. D. Small, Jr., J. C. Scaiano, J. Amer. Chem. Soc., 100, 4520, (1978). S. L. mrov, "Handbook of Photochemistry", Marcel Decker, Inc. , New York, N. Y. , 1973, p. 34. J. L. Franklin, J. G. Dillard, H. M. Rosenstock, J. T. Herron, K. Draxl and F. H. Field, "Ionization Potentials, Appearance Potentials and Heats of Formation of Gaseous Positive Ions", National Bureau of Standards, Washington, 1969. S. Meyerson and D. J. McCollum, "Advances in Analytical Chemistry and Instrurentation", Vol. 2, Wiley, New York, N. Y., 1963, p. 186. F. P. Boer, T. W. Shannon and F. W. Mafferty, J. Amer. Chem. Soc., _98, 7239 (1968); J. Diekman, J. K. MacLeod, C. Djerassi and J. D. Baldeschweiller, J. Amer. Chem. Soc., _9_l_, 2067 (1969).] J. K. MacLeod and C. J. Djerassi, J. Amer. Chem. Soc., 89, 5182 (1967); D. R. Coulson and N. C. Yang, J. Amer. Chem. Soc., 8_8_, 4511 (1966). M. M. Green, J. M. Moldowan, M. W. Armstrong, T. L. Thompson, K. J. Sprague, A. J. Haas and J. J. Artus, J. Amer. Chem. Soc., 88, 849 (1976). P. J. Wagner, H. N. Schot and A. E. Kemppainen, J. Amer. Chem. Soc., _9__5_, 5604 (1973). E. S. Huyser, "Free Radical Chain Reactions", Wiley-Interscience, New York, N. Y., 1970, p. 79-81. A. Zanella and H. Taube, J. Amer. Chem. Soc., 3, 7166 (1971) . K. Schug and C. P. GLengerich, J. Amer. Chem. Soc., 101, 235 (1979) . C. G. KLehn and H. Taube, J. Amer. Chem. Soc., 88, 690 (1976). A. F. de Fourcroy and N. L. Vauquelin, Ann. Chem. (Paris, 48, 188 (1804); 88, 5 (1804); C. Claus, Justus Liebigs Ann. Chem, _5_0_, 283 (1846). A. Bino and F. Cotton, J. Amer. Chem. 800., 102, 608 (1980). P. Ford, D. F. P. Rudd, R. Gaunder and H. Taube, J. Amer. Chem. Soc., _9_8, 1187 (1968). 157. 158 . 159. 160. 161. 162. 163. 164 . 165. 166 . 167. 168. 169. 170. 171. 172 . 173 . 174 . 175 . 169 V. E. Alzarez, R. J. Allen, T. Matsubara and P. C. Ford, J; Amer. Chem. Soc., 16, 7686 (1974). B. S. Tovrog, S. E. Diamond and F. Mares, J. Amer. Chem. Soc., 101, 5067 (1979). M. Cussac, A. Boucherle and J. L. Pierre, Bull. Soc. Chim. Fr. , 1443 (1974): R. G. Gase and U. K. Pandit, J. Amer. Chem. Soc., 101, 7060 (1979). M. Plytzanopolos, G. Pneumatikakis, N. Hadjiliadis and D. Katakis, J. Inorg. Nucl. Chem, 88, 965 (1977). M. F. Cabral and J. de 0. Cabral, J. Inorg. Nucl. Chem, 88, 985 (1977) . A. W. Downs, M. R. McWhinnie, B. G. Naik and R. R. Osbourne, J. Chem. Soc. (A), 2624 (1970). F. A. Cotton and G. Wilkinson, "Advanced Inorganic Chemistry", John Wiley and Sons, 1972, p. 991. B. Bosnich and F. P. Dwyer, Aust. J. Chem, _1_9, 2229 (1966). D. K. Lavalee, M. D. Baughman and M. P. Phillips, J. Amer. Chem. Soc., 88, 718 (1977). R. D. Foust, Jr. and P. C. Ford, J. Amer. Chem. Soc., 84_, 5686 (1972). D. K. Lavallee and E. B. Fleischer, J. Amer. Chem. Soc., 84_, 2583 (1972) . R. E. Clarke and P. C. Ford, Inorg. Chem, _9_, 227 (1970). E. Tfouni and P. C. Ford, Inorg. Chem, 18, 72 (1980). P. W. Jolly and G. F. A. Stone, J. Chem Soc., 5257 (1965). R. J. NbKinney, G. Firestein andH. D. Kaesz, Inorg. Chem, 1_4, 2057 (1975) P. J. Wagner and A. E. Kerppainen, J. Amer. Chem. Soc., _9_0,’ 5896 (1968). H. D. Abruna, A. Y. Teng, G. J. Sammnels and T. J. Meyer, J. Amer. Chem. Soc., 101, 6745 (1979). B. A. beer, M. S. Thompson and T. J. Meyer, J. Amer. Chem. Soc., 102, 2310 (1980). 176 . 177. 178. 179. 180. 181. 182. 183. 184 . 185. 186. 187. 188 . 189. 190. 191. 192. 193. 170 J. Blum, I. PriBar and O. Buchman, Jerusalem Symp. Quantum Chem. Biochem, 18 (Catal. Chem. Biochem. Theory Exp.) , 265 (1979). J. R. Birks, "Photophysics of Aromatic Molecules", Wiley—Inter- science, London, 1970, p. 187. G.A. Crosby, K. W. Hipps and W. E. Elfring, Jr., J. Amer. Chem. Soc., 86, 629 (1974). -‘—_ A. J. Rest and J. J. Turner, Chem. Comm, 375 (1969). I. W. Stolz, G. R. Dobson and R. K. Sheline, J. Amer. Chem. Soc., 88, 1013 (1963). ___- M. S. Wrighton, G. S. Hammond and H. B. Gray, J. Amer. Chem. Soc., _9_2, 6068 (1970). M. S. Wrighton, G. 8. Hammond and H. B. Gray, J. Amer. Chem. Soc., 88, 3285 (1971). G. A. Hammond, D. E. DeMeyer and J. L. R. Williams, J. Amer; Chem. Soc., 81, 5180 (1969). R. J. Watts, T. P. White and B. G. Griffith, J. Amer. Chem. Soc., 81, 6914 (1975). -—~—.——— R. J. Watts, M. J. Brown, B. G. Griffith and J. S. Harrington, J. Amer. Chem. Soc., 87, 6029 (1975). N. J. Turro, "Nblecular Photochemistry", W. A. Benjamin, Inc., Reading, Mass., 1965, p.64. J. F. O'Donnell, J. T. Ayers and C. K. Mann, Anal. Chem, 81, 1161 (1965). A. J. Gordon and R. A. Ford, "The Chemist's Companoim", John Wiley and Sons, New York, N. Y., 1972, p. 435. J. I. Zink and R. M. Dahlgren, J. Amer. Cl‘mxm. Soc., 101, 1448 (1979). E. O. Forster, J. Chem. Phys., 8_7, 1020 (1962) . J. Gearien, E. Frank, M. Negany and C. Pohorny, J. Med. Chem, 1_4, 552 (1971). H. N. Al—Jallo, K. B. Prasad and K. S. Al—Dulami, J;_Chem; Soc. ((_2_)_, 2134 (1969). R. Adams, ed., "Organic Reactions", _1_, 163 (1942). 171 194. A. D. Allen, F. Bottomley, R. D. Norris, V. P. Reinsalu and C. V. Senoff, J. Amer. Chem. Soc., 88, 5595 (1967). 195. R. W. Parry, ed., "Inorganic Synthesis", 18, 13 (1970). 196. L. H. Vogt, Jr., J. L. Katz and S. E. Wibberly, Inorg. Chem, _4, 1157 (1965). 197. R. W. Callahan, G. M. Brown and T. J. Meyer, Inorg, Chem, 1_4_, 1443 (1975). 198. G. S. Hammond, J. Saltiel, A. A. Lamola, N. J. Turro, J. S. Bradshaw, D. O. Cowan, R. C. Counsell, V. Voght and C. Dalton, J. Amer. Chem. Soc., 88, 3197 (1964). 199. G. D. Gillispe and E. C. Lim, J. Chem. Phys., 88, 2022 (1976). 200. R. S. H. Liu and J. R. Edman, J. Amer. Chem. Soc., _9_9, 213 (1968). 201. R. S. H. Liu and R. 0. Campbell, J. Amer. Chem. Soc., 88, 6560 (1973). APPENDIX APPENDIX This section contains the raw experimental data used to determine the photOkinetic parameters by the methods given in the Experimental Section. The concentrations of reactants and standards, product to standard area ratios obtained from gas chromatography analysis and gas chromatograph column temperatures are listed . The additional abbreviations used in this section are: cyc = cyclohexane; C16 = hexadecane; C17 = heptadecane; C18 = octadecane; C19 = nonadecane; C20 = eicosane; AP = acetOphenone; BP = benzophenone; pr = propane; ng = gi§71,3-pentadiene;‘trP = E£§n§71,3-pentadiene; .grS = gisrstilbene;‘gfs = traggfstilbene; benpy = benzoylpyridine and act = actinometer. [VP] = 0.01 M in benzene. o Ia = [acetOphenoneJ/ 0.33. 172 173 Table 32 . Stern Volmer data for 1— (2—pyridy1)butanone.a [Q], (M) Area ZAP / Area C16 [ZAP], (M) 40/4 0.0b 0.316 0.00129 0.00103 0.202 0.000826 0.00206 0.156 0.000638 0.00310 0.123 0.000503 0.00413 0.097 0.000396 0.00516 0.081 0.000331 0.0C 0.273 0.000923 0.00058 0.203 0.000686 1.4 0.00116 0.170 0.000575 1 6 0.00175 0.135 0.000456 2 0 0.00233 0.118 0.000399 2 4 0.00291 0.102 0.000346 2.7 a313 mm, gc Column B at 120°C, Q = 1,3—Pentadiene; hbenzene solvent, [288] = 0.0508 M, [C16] = 0.00139 M, [C16lact = 0.00696 M, Area AP / .Area C16 = 0.0169, Ia = 0.00078 81‘1; Cacetonitrile solvent, [ZBP] = 0.0501 M, [C16] = 0.00115 M, [C16]act = 0.00765 M, Area AP / Area C16 = 0.0721, Ia = 0.0036. 81’1. Table 33 . Data for the effect of concentration of tert-butyl alcohol on ¢II for 1- (2-pyridyl)butanone.a Lt-BLOH] , (M) Area ZAP / Area C16 [ZAP] , (M) 0.0 0.299 0.00170 0.16 0.87 0.673 0.00382 0.35 3.49 0.699 0.00397 0.37 4.36 0.731 0.00415 0.38 5.23 0.754 0.00428 0.39 6.97 0.574 0.00326 0.30 abenzene solvent; 313 rm; gc Column B at 115°C; [ZBP] = 0.0534 M; [C16] = 0.00193 M; [C16lact = 0.00967 M, Area AP / Area C16 = 0.174, Ia = 0.011 81'1. 174 Table 34 . Data for the effect of concentration of l- (2—pyridyl) butanone on <1> a313 nm, gc Column B at 127° C; bbenzene solvent, [C16] act II' [ZBP] , (M) [C16] , (M) Area ZAP / Area C16 [2A9], (M) 0 0.0404b 0.00211 0.216 0.00314 0.163 0.0807 0.00423 0.134 0.00195 0,20C 0.121 0.00634 0.226 _ 0.00329 0.259 0.161 0.00845 0.160 0.00233 0,249 0.202 0.0106 0.119 0.00173 0,23d 0.04028 0.00200 0.085 0.00151 0,ng 0.0804 0.00399 0.053 0.00941 0.27f 0.121 0.00599 0.108 0.00192 0,279 0.161 0.00798 0.090 0.00160 0,309 0. 201 0. 00998 0. 059 0. 00105 0,249 = 0. 00495 M, °Area AP/ Area C16= 0. 0272, 1a =.0 00089 El "-1 ,adArea AP/ Area C16= -;1 ea 0.0544 M, Ia =0. 0019 E1 acetonitrile solvent, [C16]a ct = 0.00604 M; fArea AP/ Area C16 = 0.0573, Ia = 0.0071 E1 1; Area AP/ Area C16 = 0.178, _ 1 -1 a "’ 0.002-v El 0 Table 35 . Data for 4>_K for 1- (2-pyridyl)butanone.a Run 1b,c Run Zb'd Run 3e [ZBP]O 0.0544 M 0.0507 M 0.0753 M [C16] 0.0050 M 0.0769 M [C17] 0.0228 M Area 21318 / Area Standard: ' Unirradiated 3.077 Irradiated 0.842 0.746 2.274 -[213P] 0.00996 M 0. 0104 M 0.0196 M a313 rm, gc Column B at 138° C; bbenzene solvent; cact[C16] = 0.00499 M, Area AP/ Area C16= 0.236, Ia = 0. 0079 E1 "-1 ,ad[C16] =0. 00586 M, Area 1; eacetonitrilec solvent, [C16] act - -1 AP/ Area C16 = 0.273, Ia = O.a10 E1 0.00769 M, Area AP/ Area C16 = 0.462, Ia = 0.024 El [Cl 175 Table 36 . Stern Volmer data for 1— (3-pyridyl)butanone.a Area 3AP / Area C17 [0]. (M) [BAP], (M) 00/4 b 0.0 0.594 0.00190 - 0.00175 0.301 0.000964 0.00350 0.180 0.000577 0.00527 0.140 0.000448 0.00701 0.121 0.000388 0.00876 0.092 0.000295 0.0c 0.424 0.00138 0.00097 0.232 0.000754 1 2 0.00389 0.134 _0.000436 3 2 0.00486 0.120 0.000390 3.6 a313 nm, acetontrile solvent, gc Column B at 127°C, Q = 1,3-Pentadiene; ]”[3139] = 0.0516 M, [C17] = 0.000875 M, [016]act = 0.0584 M, Area AP/Area C16 = 0.0755, 1a = 0.029 El-l; C[3BP] 0.0499 M, [017] = 0.00089 M, 1 [016]act = 0.0561 M, Area AP/ Area C16 0.0517, Ia = 0.019 81’ . Table 37. Data for the effect of concentration of tert-butyl alcohol on ¢11 for l-(3-pyridyl)butanone.a jg-Btfl-I] , (M) Area 3AP/ Area C17 [3AP] , (M) 0.0 0.478 0.00187 0. 95 0 . 800 0 . 00313 1.90 0.940 0.00368 3.80 0.810 0.00317 4 . 75 0 . 806 0 . 00316 5 . 71 0 . 946 0 . 00370 7.61 0.705 0.00276 abenzene solvent, 313 nm, gc Column B at 130°C, [3BP] = 0.0512 M, [C17] = 0.00107 M, [C16lact = 0.00490 M, Area AP/ Area C16 = 0.127, Ia = 0.0042 El'l. 176 Table 38. Data for the effect of concentration of 1- (3-pyridy1) a butanone on (DH. [3BP], (M) (any (M) Area 3AP/ Area C17 L3AP] , (M) _g_ 0.0295b 0.00158 0.0877 0.000507 0.33c 0.0590 0.00315 0.0569 0.000656 0.43C 0.0885 0.00473 0.0653 0.00113 0,33d 0.118 0.00630 0.0464 0.00110 0,36d 0.148 0.00788 0.0369 0.00106 0,35d 0.0388e 0.00160 0.254 0.00255 0,55f 0.0620 0.00255 0.307 0.00287 0.53f 0.0776 0.00319 0.230 0.00269 0.509 0.0766 0.00319 0.220 0.00257 0.579 0.116 0.00479 0.149 0.00261 0,539 0.155 0.00638 0.098 0.00229 0.519 0.194 0. 00798 0. 080 0. 00234 0.519 a313 nm, gc Column B at 1600 C; bbenzene solvent, [C16] = 0.00457 M, act =0 0015 81 1,1Area.AP/.Area C16= acetonitrile solvent, [C16] = 0.00492 M; 0.,0499 Ia l e C:Area AP/ Area C16= 0. 0969, Ia = 0.0029 E1 act fAreaHAP/.Area.Cl6- = 0. 069, 1a = 0. 00074 El 1; 3Area.AP/ Area C16= 0. 136,1a = 0. 0014 81 1. Table 39 . Data for (1)—K for l—(3—pyridyl)butarone.a Run 1b Run 2c [3BP]O 0.0533 M 0.0577 M [017] 0.0358 M [020] 0.0251 M Area BBP/ Area Standard: unirradiated 0.746 0.684 Irradiated 0.697 0.629 -[3BP] 0. 0035 M 0. 0046 M a313 on, go Column B at 1800 C; bbenzene solvent, [C16]act = 0.00551 M, .Area.AP/.Area C16= 0. 234, 1a = 0. 0086 81 1;°acetenitr11e solvent, [C16]act = 0.0474 M, Area AP/ Area C16 = 0.108, 1a = 0.034 81’1. 177 Table 49 . Stern Volmer data for l-(4-pyridyl)butanone}:1 [Q] , (M) Area 4AP/ Area C17 [4AP] I (M) ¢O/ ‘b 0.0 0.598 0.00194 0.0038 0.349 0.00113 1. 0.0076 0.239 0.000775 2 0.0114 0.185 0.000600 3 0.0152 0.164 0.000532 3 0.0190 0.132 0.000428 4. 0.0C 0.680 0.00182 0.00384 0.383 0.00103 1 8 0.00768 0.278 0.000746 2.4 0.0152 0.209 0.000561 3.3 a313 nm, acetonitrile solvent, gc Column B at 125°C, Q = 1,3-Pentadiene. b[4BP] = 0.0502 M, (017] = 0.00106 M, [Cl6]a = 0.0057 M, Area AP/ ct Area C16 = 0.187, Ia = 0.0071 81'1. C[4BP] = 0.0504 M, [C17] = 0.00088 M, [Cl6lact = 0.00488 M, Area AP/ Area C16 = 0.08, Ia = 0.0026 81'1. Table 41 . Data for the effect of concentration of tert-butyl alcohol on (DII for l-(4-pyridyl)butanone.a [t-BIDH] , (M) Area 4AP/ Area C17 [4AP] , (M) _____ 0.0 0.083 0.000274 0 20 0.97 0.177 0.000585 0 42 1.94 0.215 0.000711 0 50 3.89 0.236 0.000780 0 55 4.86 0.248 0.000820 0 58 5.83 0.258 0.000853 0 60 7.77 0.266 0.000879 0.63 abenzene solvent, 313 nm, gc Column B at 170°C, [4BP] = 0.517 M, [C17] = 0.00108 M, [C16lact = 0.00586 M, Area AP/ Area C16 = 0.361, I = 0.014 81'1. a 178 Table 42 . Data for the effect of concentration of 1- (4-pyridy1) butanone on (bII'a [4BP], (M) [C17], (M) Area 4AP/ Area C17 [4AP], (M) 0 0.023613 0.00154 0.0509 0.00024 0.15° 0.0283 0.00185 0.0527 0.00030 0.17° 0.0378 0.00246 0.0368 0.00028 0.15° 0.0472 0.00308 0.0724 0.00068 0.18(1 0.0708 0.00461 0.0513 0.00072 0.20‘1 0.0943 0.00615 0.0395 0.00074 0.20C1 0.118 0.00769 0.0389 0.00092 0.25(1 0.0222° 0.00098 1.208 0.00362 0.57f 0.0444 0.00196 0.614 0.00368 0.58f 0.0666 0.00294 0.827 0.00744 0.589 0.110 0. 00491 0. 541 0. 00813 0.63g 3313 nm, gc Column B at 172°C. bbenzene solvent, [C16] = 0. 005 M. _1 act °Area AP/ Area C16 = 0. 0543, 1a = 0. 0018 81 .dArea AP/ Area C16= 0.110,Ia =.0 0036 El . eacetonitrile solvent, [C16] act = 0. 00466 M. fArea AP/ Area C16 = 0. 211, Ia = 0. 0065 81 1. gArea AP/ Area C16= 0657, Ia=0.020E11. Table 43 . Data for 0_ Kfor l— (4-pyridy1)butanone.a Run 1b Run 2C [4BP]O 0.0508 M 0.0647 M [C17] 0.025 M 0.045 M Area 4BP/ Area C17: Unirradiated 0.945 1.709 Irradiated 0.737 1.144 -[4BP] 0.0112 M 0.0214 M a313 nm, go Column B at 1750 C. bbenzene solvent, [C161act =.0 00573 M, Area AP/ Area C16= 0. 853, 1a = 0. 032 81 "1. Cacetonitrile solvent, [C161act = 0.00612 M, Area AP/ Area C16 = 0.611, 1a = 0.032. 81 1. 0 [A0 Are, ma 179 Table 44. Stem Volmer data for 1-(2-pyridv1)pentanone.a [Q], (M) Area ZAP/ Area C16 [ZAP] , (M) (PO/4 0.0b 0.767 0.00177 - 0.022 0.382 0.000879 2,1 0.044 0.274 0.000631 2,2 0.066 0.247 0.000569 2.6 0.088 0.196 0.000451 2.9 0.11 0.191 0.000440 3.1 0.0C 0.620 0.00149 - 0.012 0.380 0.000912 1.7 0.024 0.274 0.000657 2.3 0.036 0.217 0.000521 2,9 0.048 0.163 0.000391 3,9 0.060 0.144 0.000346 4, a313 nm. gc Column B at 120°C, 0 = 1.3-Pentadiene. bbenzene solvent, [2VP] = 0.0505 M, [C17] = 0.000783 M, [C16]act = 0.00479 M, Area AP/ Area C16 = 0.300, Ia = 0.0095 El . acetonitrile solvent, [2VP] = 0.0489 M, [C17] = 0.000816 M, [C16]act = 0.0056 M, Area AP/ Area C16 = 0.0663, Ta = 0.0021. 81' . 1 Table 45. Data for 0_K for 1-(2-pyridy1)pentanone.a Run lb'c Run 2°'° Run 3e [2VP]O 0.0501 M 0.0614 M 0.0450 M [C16] 0.0176 M [C20] 0.0263 0.0424 M Area ZVP/ Area Standard: unirradiated 0.740 0.632 Irradiated 0.707 0.608 0.570 -[2vp] 0.0022 M 0.00314 M 0.00441 M al313 nm- gc Column 8 at 135°C. bbenzene solvent. CIC161act = 0.00586 M, .Area.AP/ Area.C16 = 0.273, 1a = 0.010 81'1. d'[Cl6]act = 0.00542 Mn .Aree AP/.Area.Cl6 = 0.256, Ia = 0.0092 81‘1. eacetonitrile solution, [C16]act = 0.00769 M, Area AP/ Area C16 = 0.121, 1a = 0.006 81‘1. 180 Table 46. Data for the effect of concentration of 1- (2-pyridvl) c:AreaAP/AreaC16=0.111, Ia =0.0.04E1l dAreaAP/aAreaC16= q) a pentanone on II. [2VP], (M) [C16], (M) Area ZAP/ Area C16 [ZAP], (M) ¢ 0.02431° 0.00054 0.426 0.000679 0.17° 0.0365 0.00081 0.663 0.00158 0.18d 0.0402 0.00108 0.198 0.00126 0.11° 0.0486 0.00216 0.584 0.00185 0.21d 0.0804 0.00432 0.135 0.00171 0.29f 0.161 0.00864 0.192 0.00488 0.42f 0.0439 0.00246 0.211 0.00153 0,5311 0.0806 0.00491 0.107 0.00154 0. 69h 0.0161 0.00982 0.139 0.00398 0. 701 0. 0202 0. 0123 0.112 0. 00405 0.701 a313 nm, gc Column B at 1270 C. bbenzene solvent, [C16]a = 0.0054 M, 0. 241, =0 0086 81’1.°Area AP/ Area C16= 0.165, Ia= 0. 0059 . fArea AP/ 0. 322, Ia = 0. 011 81’1. gacetonitrile solvent, [C16] _1 i act= 0.069 , Ia = 0.0023 E1 . Area AP/ Area Ia Area C16= 0. 0049 M. hArea AP/a Area C16= C16 = 0.175, 1a = 0.0019 81 ’1. @3332. Data for the effect of _tert_-buty1 alcohol on 4’11 for 1— (2—pyridy1)pentanone .a [t-BLOH], (M) Area ZAP/ Area C16 [ZAPJ , (M) 1‘ 0.0 0.0768 0.000212 0.19 0.98 0.172 0.000474 0.41 1.96 0.185 0.000510 0.44 3.91 0.259 0.000714 0.62 4.90 0.260 0.000714 0.62 5.87 0.250 0.000689 0.60 7.82 0.281 0.000775 0.65 = 0. 0511 M, 0.0371, abenzene solvent. 313 nm gc Column B at 127°C, [2VP] [C16] = 0.000983 M, [C161act= 0.00469 M, Area AP/ Area C16= 1a = 0.0011 81'1. Table 43 . Stern Volmer data for l—(3-pyridy1)pentanone.a (01 , (M) 00/0 0b .0322 .0665 .100 .133 .166 000000 0.0° 0.0203 0.0407 0.0601 0.0813 0.102 a3131nmm gc Column B at 1250C, Q= 1,3—Pentadiene. bbenzene solvent, [3VP] = 0.0498 M, [C17] = 0.00087 M, [C161act = 0.00491 M, Area AP/ acetonitrile solvent, [3VP] = 0.0505 M, [C17] = 0.000833 M, [C161act = 0.00601 M, Area AP/ Area C16 Area C16 = 0.200, Ia 0.0642, Ia = 0.0026 81’ . .Area BAP/.Area C17 181 0.717 0.463 0.321 0.271 0.203 0.182 0.722 0.442 0.308 0.258 0.204 0.173 = 0.0066 81’1. 1 [3AP] , (M) C 0.0028 0.00147 0.00102 0.000863 0.000646 0.000580 0.00235 0.00135 0.000939 0.000787 0.000622 0.000527 l 51313 mm, gc Column B at = 0.001128M, [C16]act = 0.0040 E1 Table 49. Data for the effect of concentration of tertrbutyl alcohol on 4&1 for l—(3—pyridyl)pentanone.a [t-BL'OH] , (M) Area 3AP/ Area C17 [3AP], (M) ¢> 0.0 0.313 0.00128 0.41 1.01 0.548 0.00225 0.71 2.02 0.562 0.00230 0.73 4.04 0.551 0.00226 0.71 5.05 0.601 0.00246 0.78 6.06 0.677 0.00278 0.87 8.08 0.680 0.00279 0.88 145°C, benzene solvent, [3VP] = 0.0483 M, [C17] 0.00605 M, Area AP/ Area C16 = 0.0975, 1a = 182 Table 50. Data for the effect of concentration of l—(3-pyridy1) pentanone on 411.51 [3VP], (M) [C17] , (M) Area 3AP/ Area C16 gAp], (M) 9 0.03021D 0.00174 0.0797 0.000508 0.33C 0.0604 0.00348 0.0461 0.000587 0.39C 0. 0905 0 . 00522 0 . 0683 0 . 00131 0 . 42‘1 0.121 0.00696 0.0554 0.00141 0.45‘1 0.151 0.00870 0.0481 0.00153 0.50C1 0.0652e 0.00392 0.0771 0.00111 0.85f 0.0979 0.00588 0.1120 0.00241 0.84f 0.130 0.00783 0.0899 0.00258 0.909 51313 nm, gc Column B at 1520C. bbenzene solvent, [C161a ct = 0.00513 M. °Area AP/ Area C16 = 0.0435 I a = 0.0015 81'1. dArea AP/ Area C16 = 0.083, Ia = 0.0028 81'1. eacetonitrile solution, [C161act = 0.00591 M. fArea AP/ Area C16 = 0.037, Ia = 0-00146 81'1. gArea AP/ Area C16 = 0.0817, Ia = 0.0032 81’1. Table 51. Data for (1)-K for 1- (3--pyridy1)pentanone.a Run 11"" Run zb'd Run 3° [3VP]o 0.0472 M 0.05 0.0471 M [C17] 0.0357 [C19] 0.0292 M 0.0226 Area 3VP/ Area Standard: Unirradiated 0.0595 Irradiated 0.0698 0.0794 0.0564 -[3VP] 0.00457 M 0.00402 M 0.0046 M a313 mm, gc Column B at 1650C. bbenzene solvent. C1C161act = 0.00542 M, Area AP/ Area C16 = 0.159, Ia = 0.0057 81'1. C1(Cl6] = 0.00551 M, Area AP/ Area C16 = 0.188, Ia = 0.0069 81"1 e . acetonitrile solvent, [C16]act = 0.00474 M, Area AP/ Area C16 = 0.108, Ia = 0.0034 81’1. 183 Table 52 . Stern Volmer data for 1-(4-pyridyl)pentamne.° [Q] . (M) Area 4AP/ Area 017 [4AP] , (M) 00/4 b 0.0 0.789 0.00212 - 0.08 0.544 0.00146 .5 0.16 0.407 0.0010 .0 0.24 0.307 0.000827 .7 0.32 0.289 0.000778 .9 0.40 0.254 0.000684 .2 0.0C 0.848 0.00201 - 0.060 0.515 0.00122 .6 0.121 0.357 0.000848 .3 0.181 0.258 0.000613 .2 0.241 0.246 0.000584 _ .4 0.301 0.203 0.000482 .0 3313 mm, gc Column B at 1250C, Q = 1,3-Pentadiene. bbenzene solvent, [4VP] = 0.0614 M, [C17] = 0.00088 M, [C16]act = 0.0052 M, Area AP/ Area C16 = 0.269, Ia = 0.0093 81 . acetonitrile solvent, [4VP] (017) = 0.000776 M, [C161act = 0.00551 M, Area AP/ Area 016 1a = 0.0032 81' 1 -1c 0.0518 M, 0.0881, Table 53 . Data for the effect of concentration of tert-butyl alcohol on ¢II for 1-(4-pyridy1)pentanone.a fic-BIDH] , (M) Area 4AP/ Area C17 [4AP], (M) Q 0.97 0.547 0.00127 0.50 1.95 0.462 0.00107 0.42 3.89 0.661 0.00154 0.60 4.87 0.527 0.00123 0.48 5.48 0.530 0.00125 0.48 7.79 0.537 0.00128 0.49 abenzene solvent, 313 mm, 90 Column B at 158°C, [4VP] = 0.0503 M, [C17] = 0.00076 M, [C161act = 0.00553 M, Area AP/ Area C16 = 0.0708, I a = 0.0026 81' 1 184 Table 54 . Data for the effect of concentration of 1- (4—pyridyl) a pentanone on 011. [4VP] , (M) [017] , (M) Area 4AP/ Area C17 [4A8], (M) 0 0.0313b 0.00204 0.133 0.000830 0.20‘C 0.0625 0.00409 0.072 0.000901 0.21: 0.0938 0.00613 0.112 0.00210 0.25d 0.125 0.00818 0.092 0.00230 0.27 d 0.156 0.0102 0.074 0.00231 0.27 0.03168 0.00550 0.169 0.00284 0.55f 0.0422 0.00733 0.131 0.00295 0.57f 0.0969 0.00478 0.186 0.00272 0.58g 0.1290 0.00683 0.143 0.00299 0.59g 0.1610 0. 00708 0.145 0. 00305 0.609 ago Column B at 158° C, 313 nm. °benzene solvent, [C161act = 0. 00614 M. °Aree.AP/ Area C16 = 0.103, Ia =0 00422 81 1 .dArea.AP/.Area.Cl6= 0.207, -1 e f Ia = 0. 00847 81 Area 016 = 0.131, Ia 0.00472 81'1. acetonitrile solvent, [C161act = 0.00541. Area AP/ =0 00472 81 1. gArea AP/ Area C16 = 0.188, Ia = Table 55. Data for (1)-K for l-(4—pyridyl)pentanone.a Run 11) Run 2° [4VP]o 0.0458 M 0.0525 M [C17] 0.0443 M [C21] 0.0292 M Area 4VP/ Area Standard: unirradiated 0.531 1.629 Irradiated 0.398 1.209 -[4VP] 0.0115 M 0. 0135 M ‘1313 on, go Column B at 175° C. bbenzene solvent, [016]act =0.00583 M, Area AP/ Area C16= 0. 234, Ia= 0.0091 E1 1. c:acetonitrile solvent, [C161act = 0.00524 M, Area AP/ Area C16 = 0.644 M, Ia = 0.0225 81'1. 185 Table 56 . Stem Volmer data for 4-methy1—1- (2--pyl:'idyl)pentanone.a [Q] . (M) Area ZAP/ Area C16 [ZAP] . (M) 90/9 0.0b 0.473 0.00117 — 0.044 0.356 0.000882 1.4 0.088 0.297 0.000736 1.6 0.132 0.262 0.000649 1.9 0.176 0.225 0.000558 2.2 0.220 0.208 0.000516 2.3 0.0°'d 0.606 0.00143 - 0.045 0.398 0.000938 1.5 0.090 0.348 0.000821 1.8 0.136 0.281 0.000663 2.2 0.181 0.255 0.000601 2.4 0.226 0.214 0.000505 2.8 0.0°'° 0.666 0.00150 - 0.074 0.408 0.000918 1.6 0.147 0.319 0.000718 2-1 0.221 0.250 0.000562, 2-7 0.294 0.183 0.000412 3-6 0.368 0.175 0.000395 3-8 aQ = 1,3-Pentadiene, 313 nm, gc Column B at 140°C. bbenzene solvent, [YmZVP] = 0.0497 M, [C16] = 0.000843 M, [Cl6]act = 0.00534 M, Area AP/ Aoes.C16 = 0.207, 1a = 0.0074 81'1. °aoetonitrile solvent. dIyMeZVP] = 0.0505 M, [C16] = 0.000802 M, [C16]act = 0.00538 M, Area AP/ Area C16 = 0.0648, Ia = 0.0023 Ell-1. e[yMeZVP] = 0.0509 M, [C16] = 0.000765 M, [C16]act = 0.00553 Mg Area AP/ Area C16 = 0.0588, Ia = 0.0022 81'1. Table 57 . Data for the effect of concentration of tert-butyl alcohol on 411 for 4-methyl-l-(2-pyridy1)pentanone.a It-BLOH] , (M) Area 2AP/ Area C16 [ZAP], (M) 4) 0.0 0.274 0.00602 0.17 0.94 0.726 0.00159 0.45 1.98 0.869 0.00191 0.54 3.98 1.027 0.00226 0.66 4.97 1.116 0.00245 0.69 5.97 1.146 0.00252 0.70 7.95 1.210 0.00266 0.75 abenzene solvent, 313 nm, go Coluun B at 158°C, [YMeZVP] = 0.0398 M, [C16] = 0.000747 M, [C16]act = 0.00543 M, Area AP/ Area C16 = 0.113, Ia=0.00481" 1 v ‘— 186 Table 58 . Data for the effect of concentration of 4—methy1-1—(2-py— ridy1)pentanone on 911.51 [vMe2VP] , (M) [C16] , (M) Area ZAP/ Area C16 [ZAP], (M) 0.0235b 0.00192 0.121 0.000683 0.16c 0.0470 0.00383 0.0713 0.000803 0.19° 0.0705 0.00575 0.0916 0.00155 0.2l° 0.0904 0.00766 0.0777 0.00175 0.23d 0.1175 0.00957 0.0689 0.00193 0.24d 0.0475e 0.00327 0.498 0.00479 0.71f 0.0713 0.00491 0.602 0.00869 0.749 0.095 0.00654 0.458 0.00659 0.769 0.117 0.00977 0.387 0.0111 0.80g 0.119 0. 00818 0.375 0. 00902 0.77g a313 nm, gc Column B at 1300 C. bbenzene solvent, [C16]a = 0.00515 M. °Area.AP/.Area.C16= 0.129, Ia =0 0044 81 1 .dArea.AP/.Area C16= 0.227, Ia = 0. 0080 81‘1. eacetonitrile solvent, [C16]alct = 0. 0057 M; fArea,Ap/ .Area C16 = 0.184, la = 0. 007 81 1. 3Area AP/ Area C16= 0.307, 15 = 0.12 E1 1. Table 59. Data for (1)-K for 4-methy1—l- (2-plyridy1)pentanone.a Run 11° Run 2° [yMeZVP10 0.0421 M 0.0400 M [C16] 0.00117 M [C20] 0.0175 M Area YMZVP/ Area Standard: unirradiated 1.030 6.134 Irradiated 0.942 3.459 —[YMe2VP] 0.0036 M 0.0174 a313 nm, go Coluun B at 138° C. bbenzene solvalt, [C16]act = 0.00441 M, Area AP/ Area C16= 0.559. Ia = 0. 016 E1 1.cacetonitri1e solvent, -1 [Clslact = 0.0057 M, Area AP/ Area C16 = 0.58, Ia = 0.22 El . *— 187 Table 60 . Stern Volmer data for 3-methyl-1- (3-pyridyl)butanone.a [Q], (M) Area 3AP/ Area Cl7 [BAP] , (M) 00/4 ‘b 0.0 0.600 0.00176 - 0.0068 0.381 0.00112 1.6 0.0136 0.276 0.000810 2.2 0.0204 0.200 0.000587 3.0 0.0273 0.172 0.000505 3.5 0.0341 0.148 0.000434 4.1 0.0°'° 0.483 0.00160 - 0.0039 0.330 0.00110 1.5 0.0077 0.255 0.000847 1.9 0.0116 0.204 0.000677 2.4 0.0155 0.177 0.000588 2.7 0.0194 0.146 0.000485 3.3 0.0°'e 0.612 0.00187 - * 0.0053 0.414 0.00126 1.5 0.0107 0.307 0.000936 2.0 0.0159 0.242 0.000738 2.5 0.0213 0.128 0.000665 2.8 0.0266 0.169 0.000512 3.6 a313 rm, gC'Column B at 140°C, Q = 1,3-Pentadiene. nbenzene solvent, [BMeasp] 0.0503 M, [C17] = 0.000802 m, [C16]act = 0.00547 M, Area AP/ .Area.C16 0.152, Ia = 0.0055 81’1. °aoetonltrile solvent. dIBMe3BP] 0.0518 M, [C17] = 0.00091 M, [C161act = 0.00563 M, Area AP/ Area C16 0.055, Ia = 0.0021 81'1. °[8Me3881 = 0.0407'nn [C17] = 0.000833Mi [C16]act = 0.0055 M, Area AP/ Area C16 = 0.0554, Ia = 0.0020 81" . Table 61 . Data for the effect of concentration of tert—butyl alcohol on 9H for 3-methyl-1- (3-pyridy1)butanone.a Lt-BLOHLL (M) Area 3AP/ Area C17 [3AP] , (M) 4 0.0 0.218 0.00070 0.33 1.0 0.463 0.00148 0.70 2.0 0.476 0.00152 0.72 4.0 0.470 0.00151 0.71 5.0 0.486 0.00156 0.74 6.0 0.455 0.00146 0.70 8. 0.371 0.00119 0.56 abenzene solvent, 313 nm, gc Collmn B at 142°C, [BM-338m = 0.0495 M, [C17] =0.0088 M, [c161act = 0.00562 M, Area AP/ Area C16 = 0.574, Ia=0.0022 81’1. 188 Table 62 . Data for the effect of concentration of 3-methyl—1— (3—pyridyl) butanone on 911.11 [BMeBBPJ , (M) [C1714 (M) Area 3AP/ Area on [3APL (M) 0 0.0230° 0.00167 0.274 0.00167 0.25° 0.0461 0.00333 0.162 0.00197 0.28c 0.0691 0.00500 0.252 0.00461 0.31d 0.0921 0.00667 0.199 0.00486 0.33C1 0.1150 0.00833 0.157 0.00479 0.33° 0.0267° 0.00180 0.493 0.00325 0.67f 0.0400 0.00269 0.702 0.00691 0.779 0.0534 0.00359 0.594 0.00780 0.879 0.0667 0.00449 0.447 0.00735 0.85g a313 rm, gc Colum B at 170°C. bbemzene solvent. WCM] = 0.00577 M, Area AP/ Area C16 = 0.174, Ia = 0. 0067 81"1‘1act[Cl6]=0. 00681 M, Area AP/ Area C16 = 0.321, 1a =0. 015 81 1. ea cetonitrile solvent, [C161act= 0.00519 M. fArea AP/ Area C16 = 0.138, Ia =.0 0048 81 1. 9Area AP/ Area C16 = 0.254, Ia = 0.0047 8171. Table 63 . Data for d>_ Kfor 3—methy1-1-(3-pyridy1)butaxme. Run 1° Run 2° [BMeBBP]0 0.0691 M 0.0534 M [C17] 0.03 M 0.03 M Area BMe33P/ Area C17 Unirradiated 0.945 0.786 Irradiated 0.886 0.706 -[BMeBBP] 0.0043 M 0. 0544 M 3313 nm, 9:: Column B at 170° C. bbenzene solvelt, [C161act='o 00481 M, Area AP/ Area C16 = 0. 307, 1a =.0 0089 E1 1.caceta'litri1e solvelt, 0.00555 M, Area AP/ Area C16 = 1. [C161act = 0.118, Ia = 0.0044 El 189 Table 64 . Stern Volmer data for 3-methy1--1--(4-pyridy1)butanonrle.a [01, (M) Area 4AP/ AreaC17 MAP]. (M) 60/4. b 0.0 3.635 0.00444 - 0.0208 2.106 0.00257 1.7 0.0417 1.318 0.00161 2.8 0.0° 2.335 0.00572 - 0.0180 . 1.296 0.00317 1.8 0.0361 0.942 0.00231 2.5 0.0541 0.683 0.00167 3.4 0.0722 0.530 0.00130 4.4 0.0902 0.460 0.00113 5.1 a313 nm, gc Column B at 165°C, acetonitrile solvelt, Q = Ethyl sorbate. °[8Me481>] = 0.0508 M, [017] = 0.000399 M, [C161act = 0.00501 M, Area AP/ Area C16 = 0.283, 1a = 0.0095 81'1. °[8Me481>] = 0.0499 M, [C17] = 0.008 M, [C16]act = 0.00606 M, Area AP/ Area C16 = 0.236, 1a'= 0.0095 81'1 Table 55. Data for the effect of concentration of tert-butyl alcohol on (111 for 3-methyl-1—(4-pyridy1)butanone.a fi-BlflI-I] ,AM) Area 4AP/ Area C17 HAP] , (M) 0 0.0 0.769 0.00199 0.16 0.96 1.428 0.00357 0.29 3.85 1.647 0.00412 0.33 4.81 2.441 0.00611 0.51 5.77 2.471 0.00619 0.50 7.69 2.219 0.00555 0.49 abenzene solvent, 313 nm, go Coluun B at 165°C, [8Me4BP] = 0.0494 M, [C17] = 0.000818 M, [C16]act = 0.046 M, Area AP/ Area C16 = 0.0406 M, Ia = 0.013 E1 190 Table 66 Data for (11-K for 3-methy1-l— (4-pyridy1) butanonea Run.1° Run 2° [8Me4BPlo 0.0495 M 0.0498 M [C17] 0.0400 M 0.0400 M .Area 8Me4BP/ Area.C17: unirradiated 0.974 1.037 Irradiated 0.877 0.748 —[8)e488] 0.0094 M 0.0139 M a313 nm, go Colum B at 165°C. °benzene solvent, [C161act = 0.0046 M, .Area.AP/.Area.C16 = 1.148, Ia = 0.018 81'1. °acetonitrile solvent, [C16lact = 0.0061 M, Area AP/ Area C16 = 0.442, Ia = 0.035 81‘1. Table 67. Stem Volmer data for 4-methy1-1- (4-pyridyl) pentanonea [01. (M) Area 4AP/ Area (:17 MAP). (M) 90/9 0. 0.703 0.00165 ' 0.26 0.473 0.00111 1.5 0.52 0.344 0.00081 2.0 0.78 0.295 0.00069 2.4 1.04 0.255 0.00060 2.8 1.31 0.216 0.00051 3.3 0.0c 0.913 0.00275 - 0.171 0.615 0.00185 1.5 0.342 0.476 0.00143 1.9 0.514 0.370 0.00111 2.4 0.645 0.334 0.00101 2.7 0.856 0.285 0.00086 3.2 51313 rm, gc Column B at 140°C, Q = 1,3-Pe1tadiene. bbenzene solvent, [W] = 0.0538 M, [C17] = 0.000768 M, [C161act = 0.00571 M, Area AP/ Area C16 = 0.233, Ia = 0.0089 81'1. °aoetonitr' e solvent, [YMe4VP] = 0.0503 M, [C17] = 0.000984 M, [C16lact = 0.00505 M, Area AP/ Area C16 = 0.134, Ia = 0.0045 81’1. 11313 nm, gC Column B at 140°C, benzene solvent, [YMe4VP] Table 68. 191 Data for the effect of concentration of tert-butyl alcohol for 4-methyl-l— (4-pyridy1) pentanone .a 0 °n II [t-BLDH] l (DmobNI-‘O 0 000000 (M) Area 4AP/ Area C17 0.344 0.860 0.950 0.994 0.980 0.694 MAP] 1 (M) 0.00083 0.00207 0.00229 0.00240 0.00236 0.00167 = 0.0504 M, [C17] = 0.000788 M, [C161act = 0.00577 M, Area AP/ Area C16 = 0.127, Ia = 0.0016 81'1. Table 69. Data for the effect of concentration of 4—methy1-1— (4-pyridy1)pentanone on 911.51 [YMe4VP], (M) [C17] , (M) Area 4AP/ Area C17 [4AP], (M) 4 0.0283b 0.00190 0.0896 0.000521 0.15c 0.0378 0.00253 0.0787 0.000609 0.18° 0.0473 0.00317 0.0597 0.000579 0.17c 0.0709 0.00475 0.1120 0.00174 0.19d 0.0946 0.00633 0.0880 0.00170 0.19d 0.118 0.00792 0.0773 0.00187 0.21d 0.0234° 0.00115 0.366 0.00129 0.52f 0.0279 0.00139 0.317 0.00135 0.55f 0.0465 0.00231 0.177 0.00125 0.57f 0.0698 0.00346 0.458 0.00485 0.579 0.0931 0.00462 0.341 0.00482 0.569 0.116 0. 00577 0. 282 0. 00498 0.589 11313 nm, go Column B at 167° C. °oenzene solvent, [C16]al = 0. 00575 M. °AreaAP/AreaC16=0. 0918, Ia =.0 0034 81 1 °Area.AP/ Area C16= 0. 238, Ia = 0. 0088 81 1. eacetonitrile solvent, [C161act =0.0045 M, -1 Ia_= 0. 0024 81 1. 9Area.AP/ Area.C16= 0.0086 81 192 Table 70. Data for 111-K for 4-methy1-1-(4—pyridy1)pentanone.a [YMe4VP10 [C17] [C21] Area yNke4VP/ Area Standard: Unirradiated Irradiated -[YMe4VP] a313 rm, 9c Column B at 165°C. bbenzene solvent, 1C161act = 0.00559 M, Area AP/ Area C16 = 0.268, 1a [C16]act = 0.0057 M, Area AP/ Area C16 = 0.58, Ia = 0.22 81" . Run 1b Run 2C 0.0459 M 0.0455 M 0.045 M 0.0246.M 0.696 1.558 0.630 1.146 0.0043 M 0.012 M = 0.010 81'1. Cacetonitrile solvent, 1 Table 71. Stern Volmer data for l- (2—pyridy1)butanone hydrochloridea [Q]z (M) Area ZAPHCl/ Area C16 0.0b 0.216 0.0063 0.198 0.0126 0.195 0.0189 0.178 0.0252 0.153 0.0315 0.164 0.0° 0.271 0.046 0.149 0.093 0.117 0.139 0.110 0.186 0.088 0.234 0.081 [ZAPHCl] , (M) 0 0.000613 -_ 0.000562 1 2 0.000554 1 2 0.000506 1.3 0.000435 1 4 0.000466 1 4 0.000782 0.000430 0.000337 0.000317 0.000254 0.000234 11313 nm, gc Column B at 108°C, acetonitrile solvent, Q = 1.3-Penta- diene. b[ZBPm1] = 0.0251 M, [C16] = 0.000966 M, [C161act = 0.0055 M, Area AP/ Area C16 = 0.164, 1a = 0.006 81' . 1 °[28m:l] = 0.0284 M, [C16] = 0.00981 M, [C161act= 0.00504 M, Area AP/ Area C16 = 0.208, 1a = 0.007 81'1 193 Table 72. Data for the effect of concentration of tert-butyl alcohol on 1’11 for 1- (2-pyridy1) pentanone hydrochloride."1 [t—Buon], (M) Area 2APHC1/ Area C16 [ZAPHC1] , (M) 0 0.0 0.145 0.000431 0.14 0.99 0.188 0.000558 0.082 1.98 0.202 0.000600 0.12 3.97 0.235 0.000698 0.14 _ 4.95 0.242 0.000719 0.14 5.94 0.237 0.000704 0.14: 7.93 0.236 0.000701 0.14 abenzene solvent, 313 nm, go Column B at 111°C. [28PHC1] = 0.0509 M, [C16] = 0.00101 M, [C161act = 0.00458 M, Area AP/ Arae C16 = 0.0165, Area C16 = 0.0808, Ia = 0.0027 81’ Table 74. Data for 4__K for 1- (2-pyridy1) butanone hydrochloride.a [ZBPKZ1] [C16] Area My Area C16: Unirradiated Irradiated -[ZBPHCl] 1 0.0496 M 0.0337 M 0.659 0.633 0.0020 M I = 0.0050 81’1. a Table 73. Data for the effect of concentration of 1— (2—pyridy1) butanone hydrochloride on 411.° [ZBPIIIl] , (M) [C16] , (M) Area 2APHCl/ Area C16 (2APHC11, (M) a» 0.0231 0.00173 0.0529 0.000269 0.097b 0.0461 0.00345 0.0202 0.000305 0.14° 0.0692 0.00518 0.0207 0.000315 0.12° 0.0922 0.00690 0.0148 0.000300 0.ll° 0.1150 0.00863 0.0118 0.000299 0.11C 11313 nm, acetonitrile solvent, gc Column B at 138°C, [C161act = 0.00498 M. °Area AP/ Area C16 = 0.0405, Ia = 0.0013 814. °AreaAP/ —*)_V_?......T.:Z . .15. ( ..., j t, 8......5. 81“.. .1 1.2. 3— 194 Table 74 . Continued . a313 nm, acetonitrile solvent, gc Colu'nn B at 1350C, [C161act = 0.0511 M, Area AP/ Area C16 = 0.187, Ia = 0.0064 814. Table 75 . Data for ¢_K for 1- (3-pyridyl) butanone hydrochloridea [3BPI-C110 0.0552 M [C17] 0.0395 M Area 3BPHC1/ Area C17: unirradiated 0.456 Irradiated 0.408 -[3BPI-I:l] 0.0058 M 8‘313 rm, acetonitrile solvent, gc Column B at 1700C, [C161a ct = 0.0056 M, Area AP/ Area C16 = 0.456, Ia = 0.17 814. Table 76 . Data for «1_K for 1— (4-pyridy1)butanone hydrochloride.‘1 [4BPHC1]O 0.0504 M [C17] 0.0375 M Area 4BPI-Cl/ Area C17: Unix-radiated 0.533 Irradiated 0.481 -[4BPI'C1] 0.0049 M °3l3 nm, acetonitrile solvent, go Column B at 170°C, [C161act = 0.00532 M, Area AP/ Area C16 = 0.711, Ia = 0.025 814. Table 77. Data for the effct of concentration of l- (3-pyridy1) butanone hydrochloride on (111 . [3BPHC1] , (M) [C17] , (M) Area 3AP11C1/ Area C17 [3APHC1] , (M) 0 0.023b 0.00179 0.0984 0.000645 0.20C 0.045 0.00358 0.0527 0.000691 0.21c 0.091 0.00176 0.0403 0.000260 0.27d 0.114 0.00896 0.0311 0.000109 0.26°- 0.023° 0.00167 0.159 0.000972 0.18f 0.046 0.00336 0.0993 0.00122 0.235 0.078 0.00569 0.123 0.00256 0.22g 0.092 0.00669 0.112 0. 00274 0. 239 aacetonitrile solvent, 313 nm, gc Column B at 170°C.b [C16] act= 0.00859.M.. gArea.AP/.Area C16 = 0. 033, Ia = 0. 0019 -81 1 .°Area.AP/ Area C16 = 0. 108'1a = 0. 0062 81 [C161act = 0. 00555 M. Area AP/ .Area.C16 = 0.311, Ia = 0.012 E1 4. 9Area.AP/.Area.Cl6 = 0.611, Ia = 0.023 81’1 Table 78 . Stern Volmer data for 1- (4-pyridyl) butanone hydrochloridea [Q], (M) Area 4APHC1/ Area C17 [4APH:1] , (M) °o/‘1’ 0.0° 0.389 0.000458 - 0.0053 0.316 0.000372 1.2 0.0106 0.289 0.000341 1.4 0.0158 0.269 0.000317 1.5 0.0211 0.255 0.000300 1.5 0.0264 0.233 0.000275 1.7 0.0c 0.489 0.000625 - 0.027 0.284 0.000363 1.8 0.081 0.165 0.000211 3.0 0.108 0.138 0.000177 3.6 0.136 0.119 0.000152 4.2 a313 m), gc Column B at 140°C , acetonitrile solvent, Q = 1, 3-Pentadiene, bl4BPKZl] = 0.0233 M, [C17] = 0. 000385 M, [C161act='o 00524 M, Area AP/ Area C16 = 0.157,I = 0. 0055 814°[48P801] = a0. 0228 M, [C17]= 0.000418 M, [C16] = 0.00476 M, Area AP/ Area C16 = 0.199, Ia = 0.0063 81’1. act .11- 196 Table 79. Data for the effect of concentration of tert-butyl alcohol on 011 for 1—(3-pyridyl)butanone hydrochloride.a [t-BLDHL (M) Area 3API-II1/ Area C17 [3API-K21] , (M) 0 0.0 0.141 0.000469 0.23 0.95 0.190 0.000639 0.31 1.90 0.201 0.000668 0.33 3.90 0.256 0.000851 0.42 5.70 0.249 0.000828 0.41 7.60 0.211 0.000701 0.34 abenzene solvent, 313 nm, go Column B at 178°C, [3BPHCl] = 0.0463 M, [C17] = 0.000908 M, [C16]act = 0.00859 M, Area AP/ Area C16 = 0.272, I = 0.016 El-l. a Table 80. Stern Vblmer data for l-(3-pyridy1)butanone hydrochloride.° [Q], (M) Area 3APHI1/ Area C17 [3API~I21] , (M) 40/4 b 0.0 0.993 0.00137 - 0.071 0.781 0.00108 1.3 0.106 0.703 0.00097 1.4 0.141 0.633 0.00087 1.6 0.0C 0.411 0.000662 - 0.035 0.331 0.000533 1.2 0.071 0.300 0.000483 1.4 0.108 0.268 0.000432 1.5 0.141 0.250 0.000403 1.6 0.176 0.224 0.000361 1.8 a313 1811, go Column B at 1400C, acetonitrile solvent, Q = 1,3-Penta- diene. °[38PHC1] = 0.0252 M, [C17] = 0.000377 M, [C16]act = 0.00535 M, Area AP/ Area C16 = 0.132, Ia = 0.0047 814. °[38PHCl] = 0.0169 M, [C17] = 0.00044 M, [C161act = 0.00613 M, Area AP/ Area C16 = 0.065, Ia = 0.0026 81'1. 197 Table 81 . Data for the effect of concentration of 1-(4-pyridy1) butanone hydrochloride on 0 II . a [488881] , (M) [C17], (M) Area 4APHCl/ Area C17 [4APHIZl], (M) 4 0.020 0.00143 0.0516 0.000226 0.094° 0.041 0.00285 0.0258 0.000225 0.094° 0.061 0.00428 0.0254 0.000332 0.14 ° 0.081 0.00571 0.0162 0.000283 0.12 ° 0.101 0.00713 0.0124 0.000271 0.11 ° 0.121 0.00856 0.0081 0.000212 0.08 ° a313 nm, gc Column B at 1600C, acetonitrile solvent, [C16] a ct = 0.00573 M. °Area AP/ Area C16 = 0.053, Ia = 0.0020 814. °Area AP/Area C16 = 0.132, Ia = 0.0051 81'1. Table 82 . Data for the effect of concentration of tert-butyl alcohol on 411 for 1-(4-pyridy1)butanone hydrochloride.a [emmL(m Me4mmuAmaa7 ammu,m) 4 1.85 0.069 0.000164 0.063 3.71 0.129 0.000307 0.11 4.65 0.159 0.000379 0.14 5.56 0.139 0.000331 0.12 7.41 0.136 0.000324 0.12 E1313 mn, gc Column B at 1600C, benzene solvent, [4BPHC1] = 0.0424 M, [C17] = 0.000778 M, [C161act = 0.0045 M, Area AP/ Area C16 = 0.0897, Ia = 0.0027 81'1. 198 Table 83. Stern‘VOlmer data for l-(2-pyridy1)pentanone hydrochloride.a [Q], (M) Area 2APHC1/ Area C16 [2APH21] , (M) «no/4) 0.0 0.290 0.00580 - 0.086 0.199 0.00398 1.5 0.188 0.169 0.00338 1.8 0.257 0.135 0.00270 2.2 0.342 0.110 0.00220 2.7 0.428 0.105 0.00210 2.8 a313 nm, gc Column B at 135°C, acetonitrile solvent, Q = 1,3-Penta- diene, [2VPI-Ill] = 0.0259 M, [C16] = 0.0068, [C16]a = 0.00604 M, .Area AP/ Area C16 = 0.154, Ia = 0.0062 81’1. ct Table 84 . Data for the effect of concentration of tert-butyl alcohol on (111 for l- (2-pyridyl) pentanone hydrochloridea [t-BIDH]_L (M) Area 2APHC1/ Area C16 [ZAPHCl], (M) 0 0.0 0.108 0.00155 0.14 0.91 0.120 0.00173 0.15 1.82 0.143 0.00206 0.18 3.65 0.171 0.00246 0.21 4.56 0.193 0.00277 0.24 7.29 0.218 0.00312 0.27 abenzene solvent, 313 nm, gc Column B at 135°C, [2VPI-I21] = 0.0495 M, [C16] = 0.00489 M, Area AP/ Area C16 = 0.707, Ia = 0.023 814. Table 85 . Data for the effect of concentration of 1-(2—pyridy1) pentanone hydrochloride on 0111.51 12mm], (M) 5161, (M) Area 2APHC1/ Area C16 [ZAPI-Cl], (M) 4> 0.024 0.00159 0.0927 0.000437 0.12° 0.049 0.00319 0.0486 0.000456 0.12° 0.073 0.00478 0.0734 0.000313 0.12C 0.097 0.00637 0.0442 0.0000828 0.11c 0.121 0.00796 0.0321 0.0000751 0.088° a313 rm, gc Column B at 138°C, acetonitrile solvent, [C161act = 0.0058 M, °Area AP/ Area C16 = 0.0971, Ia = 0.0037 81'1. °Area.AP/ Area.C16 = 0.221, Ia = 0.0055 81'1. 199 Table 86. Data for nyK for 1-(2—pyridyl)pentanone hydrochloride.a [MI-C110 0.0498 M [C16] 1 0.0365 M Area ZVPI-ICI/ Area C16: Unirradiated 0.566 Irradiated 0.512 -[2VPI'C1] 0.0048 M a313 nm, acetonitrile solvent, [C16] = 0.00511 M, Area AP/ Area C16 = _1 act 0.388, Ia = 0.013 E1 , gc Column B at 135°C. Table 87. Stern Volmer data for 1- (3—pyridyl) pentanone hydrochloridea [Q], (M) Area 3API-C1/ Area C17 '[3APnc1], (M) (no/4 0.0° 0.470 0.000676 - 0.10 0.354 0.000509 1.3 0.20 0.285 0.000410 1.7 0.30 0.182 0.000262 2.6 0.40 0.172 0.000247 2.8 0.50 0.139 0.000200 3.5 0.0° 0.328 0.000826 - 0.09 0.253 0.000637 1.5 0.199 0.211 0.000531 1.8 0.298 0.151 0.000380 2.5 0.397 0.123 0.000310 3.0 0.496 0.101 0.000254 3.7 b aacetonitrile solvent, 313 nm, go Column B at 135°C. Q = 1,3-Penta- diene, [3VPHC1] = 0.0268 M, [C17] = 0.000393 M, [C16] = 0.00592 M, .Area AP/ Area.C16 = 0.628, Ia = 0.025 81'1. °Q = Ethyl sorbate, 0.0497 M, [C17] = 0.000688 M, [C161act = 0.00538 M, Area AP/ 0.235, Ia = 0.0084 81‘1. [3VPHCl] Area C16 200 0.254, Ia = 0.010 81' a313 nm, gC Column B at 170°C, acetonitrile solvent. b[C16] 0.00525 M, Area AP/ Area C16 = 0.238, 1a = 0.0083 E1 . 0.00613 M, Area AP/ Area C16 1 l c act - [C161act = Table 88 . Data for the effect of concentration of 1- (3-pyridy1) pentarnone hydrochloride on 0n . a [3VPHCl], (M) [C17], (M) Area 3API-IC1/ Area C17 [3APHC1], (M) 4) 0.0467 0.00321 0.178 0.00209 0.26° 0.0701 0.00481 0.179 0.00315 0.29C 0.0934 0.00642 0.148 0.00348 0.30C 0.1170 0.00802 0.115 0.00358 0.31c Table 89 . Data for the effect of corncentration of tert-butyl alcohol on 111 for l-(3-pyridy1)pentanone hydrochloride.a [t-BLDH], (M) Area 3APHC1/ Area C17 [3APHC1], (M) 9 0.0 0.655 0.00221 0.21 1.05 0.704 0.00238 0.23 1.85 0.743 0.00251 0.24 3.71 0.800 0.00270 0.26 4.99 0.789 0.00265 0.26 5.56 0.818 0.00275 0.27 7.41 0.744 0.00251 0.24 11313 nm, go Column B at 176°C, benzene solvent, [3VPH21] = 0.0497 M, [C17] = 0.000922 M, (C161act = 0.00504 M, Area AP/ Area C16 = 0.302, _ -1 Ia — 0.010 E1 . (Table 90. Data for 9+8 fOr 1—(3=pyridy1)pentanone hydrochloride.a [3178112110 0.0409 M [C17] 0.0367 M Area 3VPHL‘I/ Area C17: 1 Unirradiated 0.618 Irradiated 0.500 -[3VPI-Cl] 0.0095 M a313 m), acetonitrile solvent, [C16]a ct = 0.005041M, Area AP/ Area C16 = 1 0.235, Ia = 0.0079 81" , go Column B at 180°C. 201 Table 2] . Stern Volmer data for 1- (4-pyridy1)pentanone hydrochloride.“1 [Q], (M) Area 4APHC1/ Area C17 [4API-1Cl] , (M) (no/0 0.0b 0.359 0.000816 — 0.172 0.216 0.000491 1.7 0.343 0.164 0.000373 2.2 0.515 0.134 0.000305 2.7 0.859 0.101 0.000230 3.7 0.0C 0.487 0.00123 - 0.173 0.406 0.00103 1.2 0.346 0.282 0.000715 1.9 0.520 0.216 0.000547 2.3 0.693 0.193 0.000489 2.6 0.866 0.149 0.000378 3.3 0.0d 0.380 0.000806 - 0.172 0.263 0.000558 1.5 0.344 0.192 0.000407 2.1 0.517 0.147 0.000312 2.7 0.689 0.125 0.000265 3.2 0.861 0.106 0.000225 3.7 0.08 0.921 0.00148 — 0.228 0.591 0.000951 1.5 0.456 0.521 0.000839 1.8 0.684 0.417 0.000671 2.2 0.911 0.353 0.000568 2.6 1.139 0.310 0.000499 2.9 0.0f 0.770 0.000835 - 0.00690 0.752 0.000815 1.0 0.0104 0.749 0.000811 1.0 0.0138 0.742 0.000804 1.0 0.0173 0.671 0.000727 1.0 » ..— aacetonitrile solution, gc Column B at 140°C. bQ = 1,3-Pentadiene, 313 nm, [4VPnCl] = 0.0444M, [C17] = 0.000743 M, [C161act = 0.00618 M, .Area.AP/ Area.C16 = 0.149, Ia = 0.0061 #1'1. °Q = 1,3-Pentadiene, 313 nm, [4VPHCl] = 0.0477 M, [C17] = 0.000828 M, [C161act = 0.00541 M, .Area AP/ Area C16 = 0.226, Ia = 0.0082 81‘1. 90 = Ethyl sorbate, 313 nm, [4mm] 0.0497 M, [C17] = 0.000693 M, [C16[act = 0.00433 M, Area AP/ Area C16 0.277, Ia = 0.0080 814. °0 = E-xylene, 313 rm, [4mm] = 0.0103 M, [C17] 0.000526 M. Q = Naphthalene, 366 nm, [4VPHC1] = 0.0102 M, [C17] 0.000354 M. .e 202 Table 92 . Data for the effect of concentration of tert-butyl alcohol on 411 for 1-(4-pyridy1)pentanone hydrochloride.a [t-BLOH] L (M) Area 4API-C1/ Area C17 [4API-C1] L (M) (D 0.0 0.150 0.000500 0.11 0.97 0.136 0.000454 0.10 1.92 0.141 0.000470 0.10 3.87 0.129 0.000430 0.094 4.83 0.128 0.000427 0.094 5.80 0.125 0.000417 0.091 abenzene solvent, 313 nm, gc Column B at 165°C, [4VPHCl] [C17] = 0.00109 M, [C161act = 0.00481, Area AP/ Area C16 Ia = 0.0046 81’1. 0.0502 M, 0.142, Table 93 . Data for the effect of concentration of 1—(4—pyridyl) pentanone hydrochloride on 011 .a [4VPI-I21], (M) [C17] , (M) Area 4API-I21/ Area C17 [4APIIZ1], (M) (1) 0.0235 0.00175 0.0824 0.000442 0.099b 0.0470 0.00350 0.0423 0.000453 0.10° 0.0705 0.00525 0.0506 0.000813 0.10C 0.094 0.00700 0.0455 0.000975 0.12° 0.117 0.00875 0.0382 0.00102 0.13C aacetonitrile solvent, 313 rm, go Column B at 165°C, [C161act = 0.00436 M. °Area.AP/ Area.Cl6 = 0.116, Ia = 0.0033 81'1. °Area.AP/.Area C16 = 0.205, Ia = 0.0060 E1 . Table 94 . Data for °-n< for l- (4-pyridyl) pentanone hydrochloride. a [4VPHCl]O 0.0472 MP 0.0489.M° [C17] 0.0283 M 0.0378 M Area 4VPI-C1/ Area C17: unirradiated 0.692 0.544 Irradiated 0.634 0.500 -[4VPI-I21] 0.0037 M 0.0040 M aacetonitrile solution, gc Column B at 178°C, 313 nm. b[C16]a ct = 0.0051 M, Area AP/ Area C16 = 0.789, Ia = 0.027 814. c[C16]act = 0.00511 M, Area AP/ .Area.C16 = 0.388, Ia = 0.132 81'1. 203 Table 95 . Stern Volmer data for 4-methy1-1— (2—pyridy1)pentanone hydrochloride.a [Q]I (M) Area 2APHC1/ Area C16 [2APHCl], (M) 1o” 0.0 0.723 0.00232 - 0.06 0.555 0.00178 1.4 0.12 . 0.453 0.00145 1.6 0.24 0.352 0.00113 2.1 a313 nm, go Column B at 135°C, acetonitrile solvent, Q = 1,3-Pentadiene, [yMeZVPHZl] = 0.0479 M, [C16] = 0.00109 M, [C161act = 0.00511 M, Area AP/ Area C16 = 0.352, Ia = 0.012 81'1. Table 95 . Data for the effect of concentration of 4—nrnethyl-1- (2—pyridy1)pentanone hydrochloride on 11H .a ineZVPKZl] AM) [C16] , (M) Area ZAPHCI/Area C16 [ZAPI-Cl] , (M) 0.0235 0.00129 0.184 0.000698 0.16b 0.0470 0.00257 0.113 0.000854 0.19° 0.0705 0.00386 0.108 0.00123 0.15° 0.0940 0.00514 0.078 0.00118 0.073C 0.118 0.00643 0.036 0.000681 0.083C 51313 mu, gc Column B at 135°C, acetonitrile solvent, [C16] ct = 0.00546 M. °Area AP/ Area C16 = 0.123, Ia = 0.0045 814. Area AP/ .Area.C16 = 0.222, Ia = 0.0081 81’1. Table 97. Data for 111-K for 4-methyl-1— (2-pyridy1) pentanone hydrochloride.a [W1] 0 0.0698 M [C16] 0.0555 M Area beZVH-lCl/ Area C16: Unirradiated 0.826 Irradiated 0.744 - [yMeZVPHJl] 0.0069 M aacetonitrile solvent, go Column B at 135°C, 313 nm, [C16]alct = 0.0055 M, Area AP/ Area C16 = 0.753, 1a = 0.028 Ell-1. 204 Table 98. Data for the effect of concentration of tert-butyl alcohol on 1111 for 4-methy1-1- (2-pyridy1)pentanone hydrochloride.a [t-BLDH], (M) Area ZAPHCl/ Area C16 [2API-Cl] , (M) 4) 0.0 0.136 0.000272 0.13 0. 98 0 .192 0 . 000384 0 . 18 1.95 0.205 0.000410 0.19 3 . 90 0 . 252 0 . 000505 0 . 24 4.88 0.296 0.000593 0.28 5 . 85 0 . 250 0 . 000501 0 . 24 7.80 0.302 0.000605 0.28 abenzene solvent, 313 nm, go Column B at 135°C, [yMezvpmzl] = 0.0488 M, [C16] = 0.000681 M, [C161act = 0.00681 M, Area AP/ Area C16 = 0.0681, Ia = 0.00309 814. Table 99. Stern Volmer data for 3-methy1-l— (3—pyridyl)butanone hydrochloride.a [Q], (M) Area 3APHC1/ Area C17 [3mm] , (M) 40/4 0.0 0.795 0.00162 - 0.061 0.404 0.000826 2.0 0.121 0.339 0.000692 2.4 0.242 0.193 0.000394 4.2 0.303 0.159 0.000325 5.0 aacetonitrile solvent, 313 nm, gc Column B at 170°C, Q = Ethyl sorbate, [8Ma3BPHC1] = 0.0274 M, [C17] = 0.000558 M, [C16]act = 0.00532 M, Area AP/ Area C16 = 0.272, Ia = 0.0097 814 Table 100. Data for <1> for 3-methy1-l— (3-pyridyl)butanone -K hydrochloride.a [Blvle3BPHCl]o ’ [C17] Area MBPI-Cl/ Area C17: Unirradiated Irradiated -[EMeBBPHC1] aacetonitrile solvent, 313 nm, go Column B at 170°C, [C161act = 0.00555 M, Area AP/ Area C16 = 0.754, Ia = 0.028 814. 205 Table 101). Data for the effect of concentration of 3-methy1-l- (3-pyridyl) butanone hydrochloride on (DH .a [8Me3BPml] , (M) [C17] , (M) Area 3APnCl/ Area C17 [3APHC1] , (M) 0 0.0224 0.00149 0.277 0.00151 0.15° 0.0449 0.00298 0.135 0.00147 0.17b 0.0673 0.00446 0.202 0.00100 0.18° 0.0896 0.00595 0.172 0.000875 0.21c 0.1120 0.00744 0.155 0.000422 0.23° aacetonitrile solvent, 313 nm, gc Column B at 170°C, [C16]act = 0.00506 M. °Area AP/ Area C16 = 0.257, Ia = 0.0087 814. °Area AP/ .Area C16 = 0.533, Ia = 0.018 81'1. Table 102. Data for the effect of concentration of tert-butyl alcohol on (DII for 3-methy1-1- (3-pyridy1)butamne hydrochloridea [t-BLOI-I] , (M) Area 3API{21/ Area C17 [3APII21] , (M) (I) 0.0 0.857 0.00182 0.18 1.02 0.998 0.00212 0.21 2.05 1.063 0.00226 0.22 4.10 1.347 0.00286 0.29 5.12 1.037 0.00220 0.21 6.14 1.233 0.00262 0.25 8.19 1.171 0.00249 0.24 abenzene solvent, 313 nm, go Colum B at 170°C, [swam] = 0.0513 M, [C17] = 0.00058 M, [C161act = 0.00507 M, Area AP/ Area C16 = 0.541, Ia = 0.018 81‘1. 206 Table 103. Data for the effect of concentration of 4-methyl-1- (4-pyridy1) pentarnone hydrochloride on 0 a II' [yMe4VPI-El] , (M) [C17] , (M) Area 4API-II1/Area C17 [4APPI21] , (M) <1) 0.0230 0.00148 0.0740 0.000328 0.1 b 0.0459 0.00295 0.0387 0.000349 0.13C 0.0689 0.00443 0.0539 0.000731 0.14C 0.0919 0.00591 0.0409 0.000740 0.140 0.115 0.00739 0.0334 0.000755 0.14 aacetonitrile solvent, 313 nm, gc Column B at 170°C, [C16] ct = 0.00637 M. °Area AP/ Area C16 = 0.0632, Ia = 0.0030 814. Area AP/ Area C16 = 0.127, Ial = 0.0054 81’ 1 Table 104. Stern Volmer data for 3—nrnethyl-1-(4-pyridyl)butanone [4API-Cl] , (M) hydrochloridea Q] (M) Area MAE-CU Area C17 0.0 0.697 0.061 0.216 0.120 0.143 0.180 0.122 0.240 0.103 0.300 0.094 0.00152 0.000471 0.000321 0.000266 0.000225 0.000205 (DO/ 0 aacetonitrile solvent, 313 rm), 9:: Column B at 170°C, Q = Ethyl sorbate, [BMe4BPHC1] = 0.0501 M, [C17] = 0.000713 M, [C161act = 0.00533 M, Area AP/ Arae C16 = 0.274, Ia = 0.0097 81’ . 1 Table 105. Data for 111-K for 3-methy1—1-(4-pyridy1)butarmne hydrochloride? [BMe4BPHC1]O 0.0501 M [C17] 0.0228 M Area BMS‘BPI-Cl/ Area C17: Unirradiated 0.986 Irradiated 0.910 -[8Me4BPMC1] 0.0039 M aacetonitrile solvent, gc Column B at 165°C, [C16] act = 0.00533 M, Area AP/ Area C16 = 0.183, Ia = 0.0065 81' . 1 207 Table 106 . Data for the effect of concentration of tert-butyl alcohol on 111 for 3emethy1-l—(4-pyridyl)bntanone hydrochloride.a [t-BIDH] , (M) Area 4APHCl/ Area C17 [4APHCl] , (M) (p 0.0 0.436 0.00137 0.16 0.92 0.293 0.000924 0.12 1.84 0.305 0.000961 0.12 3.67 0.366 0.00115 0.099 4.59 0.344 0.00108 0.14 5.51 0.345 0.00109 0.15 7.35 0.299 0.000942 0.12 abenzene solvent, 313 nm, go Column B at 165°C, [ Me4BPHC1] = 0.0513 M, [C17] = 0.00103 M, [C161act = 0.00533 M, Area AP/ Area C16 = 0,347, 1a = 0.0123. Table 107. Data for the effect of concentration of 3-methy1—1— (4-pyridy1) butanone hydrochloride on (pH . a [BMe4BPHClL (M) [C17] , (M) Area 4APHC1/ Area C17 [4APKZ1],(M) a 0.0166 0.0033 0.262 0.00265 0.19° 0.0331 0.0066 0.139 0.00281 0.21° 0.0497 0.0099 0.083 0.00251 0.18° 0.0662 0.0132 0.119 0.00481 0.20° 0.0828 0.0165 0.0782 0.00394 0.16° 0.0993 0.0198 0.067 0.00406 0.17C aacetonitrile solvent, 313 nm, go Column.B at 165°C, [C16]act = 0.00661 M. °Area AP/ Area C16 = 0.204, Ia = 0.0090 81'1. °Area.AP/.Area C16 = 0.55, Ia = 0.024 81’1. Table 108 . Data for 4>_K for 4—methyl-1- (4-pyridy1)pentanone hydrochloride.a [,MNPHCIIO 0.0787 M [C17] 0.0355 M Area yMe4VPI-Cl/ Area C17: unirradiated 0.896 Irradiated 0.816 -[yMe4VPnnCl] 0.0070 M aacetonitrile solvent, go Column B at 170°C, 313 nm, [C161act = 0.00555 M, Area AP/ Area C16 = 0.820, Ia = 0,030 El'l 208 Table 109 . Stern Volmer data for 4—methyl-1-(4-pyridyl)pentannone hydrochloride.a [Q], (M) Area 4APHC1/ Area C17 [4APPI21] , (M) (Do/1) 0.0° 0.177 0.000473 - 0.121 0.141 0.000377 1.3 0.241 0.114 0.000305 1.6 0.362 0.106 0.000283 1.7 0.482 0.094 0.000251 2.3 0.0° 1.409 0.00352 - 0.223 0.821 0.00205 1.7 0.445 0.760 0.00190 1.9 0.668 0.609 0.00152 2.3 0.890 0.506 0.00125 2.8 1.113 0.443 0.00111 3.2 b aacetonitrile solvent, 313 nm, go Column B at 170°C. Q = 1,3-Penta- diene, [newnncl] = 0.0505 M, [C17] = 0.00083 M, [C161act = 0.0048 M, Area AP/ Area C16 = 0.11, Ia = 0.0035 81'1. °Q = Ethyl sorbate, [yMe4VPI-IC1] = 0.0645 M, [C17] = 0.000816 M, [C161act = 0.00481 M, .Area.AP/.Area C16 = 0.895, Ia = 0.029 81’1. Table 110 . Data for the effect of concentration of tert—butyl alcohol on 411 for 4amethy1-l-(4-pyridy1)pentanone hydrochloride.a [t-Bnfli] , (M) Area 4API-I21/ Area C17 [4APII21] , (M) 0 0.0 0.362 0.000651 0.12 0.91 0.366 0.000659 0.13 1.82 0.358 0.000644 0.11 4.00 0.375 0.000675 0.12 5.47 0.323 0.000581 0.10 7.29 0.278 0.000500 0.86 £1benzene solvent, 313 nm, go Column B at 170°C, [ Me4VPHC1] = 0.0504 M, [C17] = 0.000588 M, [C161act = 0.00681 M, Area AP/ Area C16 = 0.137, I a = 0.00622. 209 Table 111. Data for the effect of additives on (DII for 1- (4-pyridy1) pentanone . a [ZnCl ]L(M)b [4VP], (M) Area 4AP/ Area C17 MAP], (M) 4 0.0157 0.0496 0.294 0.000695 0.16 0 . 0297 0 . 0496 0 . 264 0 . 000624 0. 14 0 . 0517 0 . 04 96 0 . 257 0 . 000607 0 . 14 (MVP), (M)° 0.0101 0.0496 0.216 0.000510 0.12 lRupy] , (M)° 0.0061 0.0496 0.210 0.000496 0.11 [BrRe (CO) :]L (M) C 0.00320 0. 0188 0. 0781 0. 000185 0.042 [Re4VP], (M)c 0.000137 0.0188 0.114 0. 000331 0.061 a313 nm, go Column B at 170°C, [C161act = 0.00572’M, Area-- AP/ Area C16 = 0.116, Ia = 0.0044 814, [C17] = 0.000772 M. °aoetonitri1e solvent. C benzene solvent . Table 112 . Data for output of the optical bench? t. (hr.) Area pr/ Area cyclohexane % conversion lrr. 18° 0.0171 0.17 24° 0.0239 0.24 32° 0.0139 0.32 12° 0.0563 0.63 44° 0.218 2.4 aacetonitrile solvent, 313 nm, gc Column A at 50°C a[VP] = 0.0564 M, [cyc] = 0.00256 M. °[VP] = 0.0503 M, [cyc] = 0.00281 M. 210 Table 113. Quantun yield data for 4-acetylpyridine hydrochloride and B—xylene (BH) in acetonitrile.a [BH] , (M) Area DI'E/ Area C15 Ia, 81"1 43‘? 0.313 0.103 0.295 0.00531 0.625 0.119 0.295 0.00633 0.938 0.114 0.295 0.00608 1.251 0.130 0.295 0.00691 1.563 0.162 0.295 0.00868 1.896 0.136 0.210 0.0102 2.189 0.174 0.210 0.0130 2.501 0.175 0.210 0.0130 °3l3 nm, [4APHCl] = 0.0102 M, [C15] = 0.0123 M, go Column 8. Table 114 . Quantun yield data for 4-acetylpyridine hydrochloride and l-phenylethanol (BB) in acetonitrile .a [BI-I] , (M) Area AP/ Area C18 [C18] , (M) Ia, 814 4%“ 0.100 0.300 0.00737 0.431 0.0169 0.201 0.253 0.01020 0.267 0.0319 0.301 0.553 0.00488 0.217 0.0427 0.401 0.217 0.01704 0.187 0.0655 0.502 0.253 0.01704 0.187 0.0719 °3l3 nm, [4APHC1] = 0.01 M, Absorbance correction = 1.34, go Column A. Table 115. Quantun yield data for 3-acetylpyrid1'3ne hydrochloride and l-phenylethanol (BH) in acetonitrile.a [BI-I] , (M) Area AP/ Area C18 [C18] , (M) Ia, 814 4:?“ 0.106 0.544 0.00488 0.623 0.0166 0.106 0.189 0.01020 0.431 0.0174 0.212 0.805 0.00488 0.267 0.0322 0.318 1.022 0.00488 0.417 0.0466 0.318 0.197 0.01704 0.267 0.0489 0.502 0.129 0.03660 0.203 0.0908 51313 nm, [3API-Cl] = 0.01 M, Absorbance correction = 1.623, gc Column A. 211 Table 116. Data for the sensitized lrra' diation of c_:_i_s_-l,3- pentadiene by the pyridyl ketones .a [c-P], (M) [t-P], 0M) 8 1c+t 0.499° 0.0273 0.0708 0.50 0.661 0.0353 0.0641 0.50 0.998 0.0308 0.0534 0.47 1.001 0.0374 0.0374 0.52 1.0 (AP) 0.0397 0.0416 - 0.399C 0.0256 0.0637 0.43 0.499 0.0268 0.0538 0.44 0.588 0.0303 0.0460 0.50 0.997 0.0316 0.0316 0.51 0.997 (AP) 0.0331 0.0337 - 0.401(1 0.0203 0.0507 0.36 0.501 0.0219 0.0440 0.39 0.661 0.0240 0.0364 0.42 1.002 0.0250 0.0255 0.45 1.002 (AP) 0.0317 0.0314 - abenzene solvent, 313 nm, gc Column C. a[2VP] = 0.0492 M, [AP] = 0.1 m. °[3VP] = 0.0495 M, [AP] = 0.0943 M. °[4VP] = 0.0532 M, [AP] = 0.0938 M. Table 117. Data for the effect of water on 011 for 1-(4—pyridy1) pentanone.a [4VP] , (M) % water Area 4AP/ Area C17 [4AP], (M) (15 0.052b 1 0.730 0.00306 0.57 0.055 2 0.754 0.00316 0.58 0.063 3 0.591 0.00248 0.47 0.061C 0 0.413 0.00118 0.45 0.056 2 0.489 0.00140 0.58 0.055 3 0.455 0.00130 0.54 0.057 4 0.420 0.00120 0.50 aacetonitrile solvent, 313 nm, gc Column B at 125°C. b[C17] = 0.0014 M, [Clam = 0.00539 M, Area AP/ Area C16 = 0.160, Ia = 0.0058 814. °[C17] = 0.000933 M, [C161act = 0.00525 M, Area AP/ Area C16 = 0.111, Ia = 0.0039 81'1. 212 Table 11 8. Quantunn yield data for 4-acety1pyridine hydrochloride and 2—pr0panol(BH) in acetonitrile.a [BH] , (M) Area acetone/ Area cyc [acetone], (M) I , 81’1 4°01”: a acetone 0.126° 0.0595 0.00121 0.012 0.10 0.251 0.0818 0.00166 0.012 0.15 0.377 0.115 0.00230 0.012 0.20 0.502 0.0864 0.00175 0.0075 0.23 0.753 0.112 0.00227 0.0075 0.30 0.879 0.122 0.00247 0.0075 0.32 1.004 0.126 0.00255 0.0075 0.33 0.126° 0.0320 0.00532 0.0059 0.057 0.251 0.0519 0.00862 0.0059 0.093 0.378 0.0693 0.0115 0.0059 0.12 0.504 0.0798 0.0133 0.0059 0.14 0.630 0.0533 0.00886 0.0092 0.15 0.756 0.0595 0.00989 0.0092 0.16 0.882 0.0645 0.0103 0.0092 0.18 1.008 0.0695 0.0115 0.0092 0.20 51313 nm, gc Column F. b[4APHC1] = 0.0113 M, [cyc] = 0.00662 M. <:[4API-1221] = 0.0103 M, [cyc] = 0.0543 M. 3313 nm, gc Column F. b °[3APHC1] = 0.00992 M, [cyc] = 0.00533 M. Table 119 . Quantun yield data for 3-acety1pyridine hydrochloride arnd 2-propa1nol(BH) in acetonitrile? -1 corr [BI-I] , (M) Area acetone/ Area cyc [acetone] , (M) 1a , El (pace tone 0.501° 0.0314 0.000623 0.014 0.044 0 . 626 0 . 0210 0 . 000416 0 . 0084 0 . 049 0.752 0.0295 0.000585 0.0084 0.069 0.877 0.0319 0.000633 0.0084 0.074 1.00 0.0409 0.000811 0.0084 0.081 0.125c 0.0513 0.000837 0.018 0.047 0. 250 0. 0490 , 0. 000799 0. 018 0. 044 0 . 366 0 . 0426 0 . 000711 0 . 018 0 . 039 0.501 0.0321 0.000765 0.018 0.043 0.626 0.0459 0.000763 0.0094 0.049 0 . 751 0 . 0398 0 . 000653 0 . 0094 0 . 069 0. 870 0 . 0326 0 . 000708 0 . 0094 0 . 075 1.00 0.0244 0.000752 0.0094 0.080 [3APHC1] = 0.00973 M, [cyc] = 0.00648 M. 213 Table 120. Data for the effect of concentration of 4-acety1pyridine hydrochloride on 4m in acetonitrile . a [4APHC1] , (M) Area D'I‘E/ Area C15 [D'I‘E] , (M) (1DI‘E 0.0124 0.297 0.000167 0.0074 0.0220 0.359 0.000195 0.0077 0.0376 0.395 0.000214 0.0080 0.0470 0.411 0.000223 0.0083 0.0746 0.453 0.000246 0.0091 0.0809 0.455 0.000247 0.0091 a3l3 nm, [C15] = 0.00571 M, 1a = 0.027 Ell-1, gc Column B. Table 121. Stern Volmer data for 4-acety1pyridine hydrochloride in acetonitrile.a [4APHC1] = 0.0101 M, [cyc] [4APHCl] = 0.0105 M, [eye] 0. 00543 M. [Q] , (M) Area acetone/ Area cyc [acetone] , (M) 00/ 0 0.00142° 0.0348 0.000679 1.0 0.00427 0.0328 0.000640 1.1 0.00569 0.0304 0.000593 1.2 0.00711 0.0290 0.000566 1.2 0.0107 0.0265 0.000517 1.4 0.0142 0.0239 0.000466 1.5 0.0016l° 0.0428 0.000700 2.0 0.00807 0.0413 0.000675 2.1 0.0121 0.0391 0.000639 2.1 0.0161 0.0376 0.000615 2.2 0.0202 0.0334 0.000546 2.4 ago Column F, [2—propanol = 0.377 M. bQ = Naphthalene, 366 nm, 0.00648 M. °Q = Ethyl sorbate, 313 nm, 214 Table 12 2 . Stern Volmer data for 3—acetylpyridine hydrochloride [Q] , (M) 0.00166 0.00333 0.00498 0.00664 0.00830 0.0124 0.00408C 0.00816 0.0122 0.0163 0.0204 ago Column 1?, [2-propanol] in acetonitrile . a Area acetone / Area cyc [acetone] , (M) 4 /4> 0.0304 0.0280 0.0251 0.0242 0.0216 0.0198 0. 0323 0 . 0348 0 . 0316 0 . 0279 0 . 0250 0.000475 0.000437 0.000392 0.000378 0.000337 0.000309 0 . 000528 0 . 000569 0 . 000517 0. 000456 0 . 000409 0.0670 M. °Q = Naphthalene, 366 nm, [3APHC1] = 0.0103 M, [cyc] = 0.00519 M. °Q = Ethyl sorbate, 313 nm, [3APHC1] = 0.0125 M, [cyc] = 0.00543 M. ' Table 121 . Fragmentation data for the pyridyl ketone ruthenium (II) camplexes.a [Ru4AP], (M) [C18] , (M) Inj T Area 4VP/ Area C18 [4AP], (M) 0.005 0.0005 25030 0.0 0.0 0.005 0.0005 2806C 0.059 0.000092 0.005 0.0005 32°d° 0.057 0.000088 0.005 0.0005 320 C 0.0804 0.0013 [Ru4VP], (M) [C17], (M) Area 4VP/ Area C17 [4VP], (M) 0.0105°'° 0.0106 0.0058 0.00011 0.0105° 0.0106 0.0051 0.00012 0.0105°'e 0.0106 0.0046 0.00011 0.00454 0.00158 0.0126 0.000044 0.01029 0.00156 0.0248 0.00011 aacetonitrile solvent, gc Column B at 14 0°C . b [triphenylphosphine] = dreflux 24 hr. ereflux 48 hr. fbutyro- 0.115 M. room temperature, dark. nitrile solvent, [triphenylphosphine] = 0.058 M. gCI-IBCN solvent, [LiCl] = 1.16 M. u 215 Table 124 . Stern Volmer data for [Ru (M13) 5(l-(4-pyridyl)pentanone)] a [Ru4VP] , (M) [Q] 1 (M) Area pr/ Area cyc [Pr] , (M) (PO/4) 0.0105° 0.0 0.181 0.000395 - 0.0102 0.187 0.104 0.000297 2.2 0.0103 0.562 0.0746 0.000163 3.1 0.0103 0.937 0.0367 0.000080 6.6 0.0103C 0.0 0.108 0.000238 - 0.0101 0.099 0.0558 0.000123 2.0 0.0107 0.197 0.0406 0.0000893 2.7 0.0097 0.296 0.0395 0.0000867 3.1 0.0103 0.394 0.0304 0.0000669 3.5 0.0099 0.493 0.0251 0.0000552 4.6 ‘10 = Ethy; sorbate, acetonitrile solvent, 313 nm, gc Column A at 50°C. °[cyo] = 0.00190 M, [C17] = 0.0017 M, [cyo]act = 0.0057 M, Area pr .,’Area cyc = 0.484, [C16]act = 0.00549 M, Area AP/ Area C16 = 0.577, 1a = 0.019 El-l. C[cyc] = 0.0011 M, Area pr/ Area cyc = 0.389, [C16]act = 0.0048 M, .Area AP/ Area C16 = 0.480, Ia = 0.014 81’1. Table 125 . Stern Volmer data for [Ru N43)5(l-(3-pyridyl)pentamne)] a [BF4]2. [RuBVP] , (M) [O], (M) Area pr/ Area cycb _[pr] . (M) o/ (1 0.0101° 0.0 0.0997 (0.0) 0.00109 - 0.0098 0.060 0.0586 (0.379) 0.000642 1.7 0.0104 0.181 0.0336 (0.669) 0.000368 2.9 0.0094 0.302 0.0225 (0.570) 0.000247 4.4 0.0098d 0.0 0.0666 (0.0) 0.000128 - 0.0091 0.061 0.0372 (0.473) 0.0000716 1.8 0.0103 0.123 0.0272 (0.474) 0.0000524 2.4 0.0096 0.184 0.0243 (0.479) 0.0000468 2.7 0.0105 0.245 0.0198 (0.478) 0.0000381 3.4 ‘10 = Ethyl sorbate, acetonitrile solvent, 313 rm. hNumbers in parenthesis are Area 3VP/ Area C17. °[cyo] 0.00172 M, [C17] = 0.000978 M, [cyclact = 0.00548 M, Area pr/ Area cyc = 0.446, [Cl6]act = 0.0048 M, Area AP/ Area C16 = 0.566, Ia = 0.013 814. °[cyo] = 0.000963 M, [C17] = 0.001 M, [CYC1act = 0.00548 M,-Area pr/ Area cyc = 0.297, [C161act = 0.0048 M, Area.AP/ Area.Cl6 = 0.356, Ia = 0.010 81'1. 216 Table 126. Stern Volmer data for [Ru(NH3)5 (4-methyl—1-(4—pyridyl) pentanone” [BF 4] 2.51 [RuvMe4VP]. (M) [Q] .(M) Area Pr/ Area cyc [Pr] .(M) 40/4 0.00976° 0.0 0.256 0.000558 - 0.00953 0.201 0.129 0.000281 2.0 0.00957 0.602 0.0611 0.000133 4.2 0.0103 1.003 0.0346 0.0000754 7.4 0.00981C 0.0 0.313 0.000669 - 0.0102 0.085 0.223 0.000467 1. 4 0.0105 0.169 0.159 0.000340 2. 0 0.0102 0.254 0.128 0.000274 2. 5 0.0102 0.339 0.118 0.000229 2. 9 0.0102 0.423 0.107 0.000253 3. 3 aQ = Ethyl sorbate, acetonitrile solvent, gc Column A at SOOCblcyc1= 0.00109 M, [C17] = 0.0017 M, [Cyc1act = 0.00571 M, [C161act = 0.00594 M, .Area pr/.Area C16 = 0.504. Area.AP/ Area.C16 = 0.575, Ia = 0.019 81'1. °[cyo] = 0.00107 M, [C17] = 0.0017 M, [Cyc1act = 0.00548 M, Area pr/ Area cyo = 0.434, [C16]act = 0.0048 M, Area AP/ Area C16 = 0.539, _ -1 a "" 0016' El 0 Table 127. Stern Volmer data for [Ru(NH3) 5(3-met.hyl—1-(3—pyridyl) butanone” [BF4] 2. (Ru 81mm]. (M) (0] , (M) Area pr/ Area gc° (pr) . (M) 4’e’ ‘1’ 0.0103 0.0 0.1180 (0.0778) 0.00260 - 0.0094 0.96 0.0341 (0.175) 0.000750 3.2 0 . 0101 0 . 191 0 . 0252 (0 . 206) 0 . 000554 5 . 1 0.0102 0.242 0.0263 (0.225) 0.000578 5.3 0.0102 0.287 0.0172 (0.240) 0.000378 7.2 0. 0098 0. 382 0. 0130 (0. 329) 0.000286 9.8 aQ= Ethyl sorbate , acetonitrile solvent, 313 nm. hNumbers in parenthesis are Area 3VP/ Area C17, gc Column A at 50° C, gc Column B at 140° C. alcyc] = 0.0011 M, [C17] = 0.00192 M, [cyo]a ct = 0.00548 M, Area pr/ Area 5517c = 0.378, [C161act = 0.0048 M, Area AP/ Area C16 = 0.498, 1a = 0.14 El . 217 Table 123. Stern Volmer data for [Ru(MnI3)5(3-methyl-l-(4-pyridyl) butanone” [BF4]2.a [RUBIVE4BP11 (M) [Q] , (M) Area Pr/ Area cyc [pr] , (M) (Do/(1 0.0106 0.0 0.333 0.000946 — 0.0093 0.0577 0.192 0.000545 1.7 0.0097 0.115 0.141 0.000400 2.5 0.0090 0.173 0.102 0.000290 3.2 0.0100 0.231 0.086 0.000244 3.7 0.0101 0.289 0.067 0.000190 4.6 aQ = Ethyl sorbate, acetonitrile solvent, 313 mm, gc Column A at 50°C, [cyo] = 0.00142 M, [C17] = 0.00233 M, [cyo]act = 0.00988 M, Area pr/ Area cyc = 0.491, [C161act = 0.00608 M, Ia = 0.030 814. Table 129. Quantum yield data for [Ru(NH3)5(4-acetylpyridi.nne)] [BF 412) 'with 2-propanol(BH) in acetonitrile.a —1 [BH] , (M) Area acetone/ Area cyc Ia, E1 ¢acetone 0.201: 0.0304 0.015 0.033 0.402d 0.0323 0.015 0.035 0.602e 0.0337 0.0062 0.086 0.805 0.0426 0.0062 0.11 1.00 0.0484 0.0062 0.13 a313 rm, go Column F, [oyo] = 0.00519 M. °[Ru4AP] = 0.0099 M. °[Ru4AP] = 0.0099 M. °[Ru4AP] = 0.00961 M. e[Ru4AP] = 0.00998 M. f[Ru4AP] = 0.011 M. Table 130. Quantun yield data for [Ru (NI-I3) 5(3—acetylpyridinen [BF4]2 with 2—proparnol (BH) in acetonitrile.a -1 [BH] , (M) Area acetone/ Area cyc Ia’ E1 ¢acel 0.199: 0.0166 0.015 0.018 0.400d 0.0236 0.015 0.034 0 . 599d 0. 0209 0 . 0062 0. 054 0.7996 0.0281 0.0062 0.069 0.999 0.0327 0.0062 0.084 E“313 mm, go Column F, [cyo] = 0.00519 M. °[Ru3AP] = 0.00949 M. °[Rnn3AP] = 0.00937 M. °'°[Ru3AP] = 0.0104 M. °[Ru3AP] = 0.010 M. Table 131. [Rn4AP], (M) 0.0096b 0.0101 0.0099 0.0128 0.0104 0.0111 0.0109 C 0.00848d 0.00982 0.0107f 0.0101 0.00876 0.009943 0.00901h 0.00798 0.0104 .121r.fl!1 0.0 0.00231 0.00462 0.00770 0.0116 0.0154 756 5 595 5 OOOOO 00000 0.0 0.0503 0.00924 0.0274 0.0510 218 Stern Volmer data for [Ru(NH 3)5 Area acetone/ Area cyo 0.0338 0.0318 0.0325 0.0456 0.0306 0.0333 .0332 .0319 .0328 .0340 .0337 00000 0.0319 0.0340 0.0332 0.0335 0.0329 [acetone] , (4-acety1pyridine) ] [BF (M) a 412' 0.00061 0.00057 0.00059 0.00082 0.00055 0.00060 0.00060 0.00058 0.00060 0.00061' 0.00061 0.00058 0.00061 0.00060 0.00061 0.00059 aacetonitrile solvent, gc Column F, [cyo] = 0.0060 M, [2—pr0panol] = 0.599 M. bQ = naphthalene, 366 mm. 1,3—cyclooctadiene, 313 nm. eQ = 2,3-dimethy1but-2—ene, 313 mm. C Q = funaronitrile, 313 mm. dQ = f Q: 2,4-hexadieneol, 313 nm. 90 = 1-naphthylacetic acid, 366 nm. hQ = 2-chloronaphthalene , 366 nm. Table 132. Stern Volmer data for [R11(M13)5(3-acety1pyridine)] [BF [RIJ3AP] , (M) 0.0101 0.00994 0.0108 0.0103 0.0098 0.0113 [Q] L (M) 0.0 0.00231 0.00462 0.00770 0.0116 0.0154 Area acetone / Area cyo 0.0250 0.0163 0.0241 0.0245 0.0257 0.0236 0.00044 0.00028 0.00042 0.00043 0.00045 0.00041 aacetonitrile solvent, 366 nm, gC Column F, [cyo] = 0.0058 M, [2-pmpanol] = 0.609 M. a 412° [acetone] , (M) Table 133 . [ReZAP] , (M) 0.00101 0.00101 [Re3AP] , (M) 0.0076 0.00135 0.00104 [Re4AP] . (M) 0.00997' 0.00997 0.00997 0.00997 0.01820 [ReZBP] . (M) 0.00124 (Remap) . (M) 0.00139 (Rem) MM) 0.000386 (m1 , 1M) 0.00547 0.00118 0.00089 [Re3VP] . (M) 0.00429 [Re4VP1L (M) 0.0093 0.0113 0.0093 0.0093 0.0113 0.0124 0.0124 0.0124 219 Fragmentation data for the complexes .a [C17] . (M) 0.0115 0.0134 [C17] 1 (M) 0.0166 0.0115 0.0134 [C1714 (M) 0.00525 0.00525 0.00525 0.00525 0.0115 [C16]i(M) 0.0111 1917],(M) 0.0104 1917].(N9 0.0104 [C171,04) 0.0166 0.0115 0.0134 [C17] 1 (M) 0.0166 [€17] . (M) 0.0124 0.0093 0.0124 0.0124 0.0093 0.0093 0.0093 0.0093 rheniun (I) pyridyl ketone Inj T. Area ZAP/ Area C17 [ZAP] , (M) 235 0.00627 0.0020. 259 0.0225 0.0010 Inj T. Area 3AP/ Area C17 [3AP] , (M) 230 0.153 0.0091- 235 0.0352 0.0015 250 0.0286 0.0014 Inj T. Area 4AP/ Area C17 (4AP] ,(M) 145 0.234 0.0038 190 0.450 0.0072 200 0. 984 0. 016- 210 1 . 019 0 . 016-... 235 0.063 0.022 Inj T. Area ZBP/ Area C16 [ZBP] , (M) 235 0.0347 0.00092 Inj T. Area 3BP/ Area C17 [3BP],(M) 235 0.0449 0.0012 Inj T. Area 4BP/ Area C17 [4BP] , (M) 249 0.0125 0.00033 Inj T. Area ZVP/ Area C17 [2VP]ij) 230 0.0818 0.0030 235 0.0299 0.00075 250 0.0399 0.0010 Inj T. .Area 3VP/ Area C17 [3VPLLOM) 230 0.233 0.0085 Inj T. Area 4VP/ Area C17 [4VP] , (M) 140 0.388 0.0096 140 0.363 0.0093 180 0.545 0.013 195 0.868 0.021 195 0.852 0.022 208 1.043 0.025 223 0.983 0.024 230 1.005 0.024 aTenperature in 0C, benzene solvent, gc Column B at 130°C. 220 Table 134 . Quantum yield data for the rutheniun (II) acetylpyridine complexes . a [RuAP] , (M) [C17] , (M) Area AP/ Area C17 R114AP 0.0103 0.0158 0.0 Ru3AP 0.00917 0.0013 0.11 RUZAP 0.00846 0.00034 0.0 aacetonitrile solvent, 313 nm, gc Column B at 1250C, [C16]act - 0.00508 M, Area AP/ Area C16 = 0.541, Ia = 0.018 814. Table 135 . Photochemical data for BrRe (CO) 3(2VP)2.a Area 2AP/ Area C17 Area ZVP/ Area C17 [2VP] , (M) '0 ex ReZVP-1 0 1.366 0.00341 0. 51°c ReZVP-2 0 1.745 0.00436 0. .051)c sensReZVP-l 0 1.681 0.00420 0. 31 sensReZVP—Z 0 1.163 0.00290 0. 075° abenzene solvent, 313 nm, gc Column B at 125°C, sens = acetophenone @ 0.0494 M, [ReZVP] = 0.00697 M, [ReZVP] = 0.00586 M, [(217] = 0.00114 M, [C16] act = 0. 00538 M. °Area AP/ Area C16 = 0.475, I 0. 017 El 1. °Area AP/ Area C16 = 3. 63, Ia = 0. 13 814. UV(benzene) 465 mm (8: 3945 M 1cm4 ) 277 nm (c 15208 M 4on4 ), 6313;!“ = 6126 M4cm4. Table 136 . Photochemical data for BrRe(CO)3(3VP)2.a Area 3AP/ Area C17 Area 3VP/ Area C17 [3VP] , (M) <1>_ K Re3VP-1 0 2.19 0.00823 0.07cz:° Re3VP-2 0 4 .51 0. 0169 0 . l4 sensReBVP-l 0 3.23 0.0121 0.04g° sensRe3VP—2 0 4.27 0.0160 0.18 abenzene solvent, 313 nm, gc Column B at 130°C, sens = acetOphenone @ 0.0488 M, [Re3VP] = 0.00936 M, [ReBVP] = 0.00938 M, [C17] = 0.00170 M, [C16]alct = 0.00567. °Area AP/ Area C16 = 0.36, Ia - 0.14 814. °Area AP/ Area C16 = 3.901. UV(benzene) sh m 300 nm (e 7999 M'1cm4) l -l —l -1 276nm(810250M-cm ),e =7422M an . 313nm 221 Table 137. Photochemical data for BrRe(CD)3(4VP)2 and .BrRe(CO)3(4AP)2.a Area 4AP/ Area C17 Area 4VP/ Area C21 0 -1< Re4AP° 4.58 - 0.0725 Re4VP 0.0 1.22 0.0101 Area 4AP/ Area C17 Area 4VP/ Area C21 [4VP] , (M) (1)-K Re4VP-1° 0 7.40 0.020 0.0° e Re4VP-2 0 5 59 0.015 0.059 sensRe4VP-l 0 7.50 0.020 0.0 e sensRe4VP-2 0 4 . 89 0 . 013 0 . 035 abenzene solvent, 313 nm, go Column B at 120°C. °[Re4AP] = 0.0108 M, [Re4VP] = 0.0100 M, [C17] = 0.00115 M, [C21] = 0.006; M, [C161act = 0.00523 M, Area AP/ Area C16 = 2.154, Ia = 0.075 814, UV analysis: Re4VP prior to hv (benzene) 272 nm (c 14060 M4cm4) 342 m) (c 9726 14" cm4); Re4VP after 8 hr. hv (benzene) 272 mu (8 14590 M4cm4)_ 340 nm broad (c 8030 M4cmn4). °sens = acetophenone (a. 0.0431 M, [Re4VP] = 0.00997 M, [Re4VP]sens = 0.0101 M, [C17] 0.000975 M, [C21] = 0.00103 M, [C16]act = 0.00543 M. dArea AP/ Area C16 0.683, I;=1 = 0.0243 814. eAnltea AP/ Area C16 = 4'93’11a = 0.18 81" UV after h\) 276 nm (e 9550 M am4) 343 nm (e 8335 M“ 1 l can-1) . Table 138 . Data for thesensitized isanerization of gig-1,3-pentadiene by BrRe(CO)3(pyrid_1'.nne)2.a <1> [C-P] I (M) [t-P]L (M) B c+t 0 . 4027 0 . 0024 0 . 00574 0 . 025 0 . 5033 0 . 0022 0 . 00439 0 . 023 0.6644 0.0030 0.00458 0.032 1.007 0.0027 0.00276 0.029 0.755 (AP) 0.0491 0.0660 - abenzene solvent, 313 mm, [Repy] = 0.000488 M, [AP] = 0.103 M, gc Column C at 50°C. 222 Table 139 . Data for the sensitized isanerization of trans-stilbene by 8r8e4C0)3(pyridine)2.a [t-S] , (M) [g—S] , (M) Area E—S/ Area C18b Area g-S/ Area C18 t c 0.0080 0.0000599 1.532 (0.0035) 0.0175 0.0058 0.0100 0.0000972 1.565 (0.0044) 0.0156 0.0092 0.0199 0.0001655 1.562 (0.0088) 0.0134 0.016 0.0399 0.000360 1.604 (0.0177) 0.0146 0.086 1- 0155 (BP) 0 .0753 — - .. anoenzene solvent, 366 nm, [Repy] = 0.000488 M, [BP] = 0.103 M, go Column C. bNumbers in parenthesis are [C18] . Table 140. Data for the sensitized iscmerization of fi-lfi-pentadiene by 8r-Re(C0)3[l-(3-pyridyl)pentanone]2.a (c-P). (M) [t-P]. (M) 8 “’ca: 0.410° 0.0095 0.0238 0.36 0.501 0.0111 0.0220 0.42 0.661 0.0136 0.0206 0.51 1.00 0.0107 0.0107 0.40 0.751 (AP) 0.0165 0.0195 - 0.402 0.0073 0.0181 0.32 0.503 0.0073 0.0145 0.32 0.664 0.0078 0.0118 0.34 1.00 0.0097 0.00964 0.42 c: 1.01 (AP) 0.0143 0.0121 - abenzene solvent, 313 nm, gc Column C. b[Re3VP] = 0.000254 M, [AP] = 0.0973 M. °[Re3VP] = 0.00026 M, [AP] = 0.105 M. Table 141 . Data for the sensitized isamerization of c_i_s_-l ,3—pentadiene by BrRe (CO) 3 [1- (2-pyridyl) pentanone] 2 ? [c-P]. (M) (t-P). (M) B ¢c+t 0.492 _ 0.0011 0.00275 0.0044 0 . 504 0 . 0013 0 . 00253 0 . 0061 0.684 0.0025 0.00310 0.0085 1 . 01 0 . 0027 0 . 00260 0 . 011 0.805 (BP) 0.531 0.148 - ahenzene solvent, 313 rm, [ReZVP] = 0.00278 M, [BP] = 0.120, go Column C. 223 Table 142. Data for the sensitized iscmerization of trans-stilbene by 8r8e(co)3[1-(3epyridyl)pentanone]2.a [fig-S] , (M) [g-SJ , (M) Area t-S/ Area C18 Area 95/ Area C18 etc 0.0083 0.000236 1.445 (0.0039) 0.0471 1.99 0.0104 0.000273 1.492 (0.0049) 0.0403 1.72 0.0207 0.000335 1.505 (0.0097) 0.0246 1.42 0.0414 0.000463 1.515 (0.0194) 0.0170 1.04 abenzene solvent, 366 nm, [Re3VP] = 0.00165 M, [BP[ = 1.1016 M, gc Column D. hNumbers in parenthesis are [C18] . Table 143. Data for the sensitized isomerization of gig-1,3—pentadiene wammmbuqewewnmmmmera [grP], (N0 [trP]. (M0 8 4tfic 0.401° 0.0086 0.0214 0.77 0.501 0.0088 0.0176 0.78 1.002 0.0099 0.00987 0.88 0.751 GNP) 0.0062 0.00822 - 0.401C 0.0046 0.0116 0.58 0.501 0.0050 0.0100 0.62 0.661 0.0064 0.00963 0.80 1.002 0.0090 0.00904 1.1 1.002 (AP) 0.0039 0.00440 - 0.0080(1 0.001 0.0547 0.0016 0.0160 0.0005 0.0429 0.0025 0.0240 0.0009 0.0367 0.0032 0.0399 0.0017 0.0265 0.0041 0.998 0.0546 0.00981 0.028 0.09669 (APl) 0.0129 0.153 - 0.998 (AP2) 0.0054 0.00561 - abenzene solvent, 313 nm, go Column C. °[Re4VP] = 0.000385 M, [AP]= 0.104 M. °[8e4vp] = 0.000361 M, [AP] = 0.0978 M. °[Pe4VP] = 0.000266 M, [APl] = 0.104 M, [mm = 0.0969 M. 224 Table 144. Data for the sensitized isanerization of trans—stilbene by BrRe (CO) 3 [1- (4-pyridyl) pentanone] 2 . a b [_t-S] , (M) [9-8] , (M) Area E-S/Area C18 Area g-S/Area C18 <1> t+c 0.00799C 0.000388 - - 0.66 0.00999 0.000411 - - 0.70 0.0199 0.000682 - - 1.16 0.0399 0.000197 - - 1 26 0.202 (BP) 0.000249 - — - 0.008d 0.000357 1.644 (0.0034) 0.0768 0.67 0.020 0.000390 1.68 (0.0085) 0.0334 0.68 0.040 0.000482 1.73 (0.0169) 0.0212 0.84 0 . 0507 (BP) 0. 000531 abenzene solvent, 366 nm, go Column D. b( ) [C18] . c:[Re4VP] = 0.00361 M, [BP] = 0.995 M. lee4VP] = 0.0038 M, [BP] = 1.003 M. Table 145. Data for the sensitized iscmerization of cis-1,3-pentadiene by 8r8e(00)3(3-ebenzoy1pyridine)2.a [g—P] . (M) [E-P]. (M) B 00% 0.399 0.0080 0.0203 0.41 0.499 0.0091 0.0182 0.47 0.993 0.0111 0.0139 0.69 0.749 (AP) 0.0111 0.0148 - abenzene solvent, 313 nm, go Colum C, [Re3benzpy] = 0.000346 M, [AP] = 0.111 M. Table 146. Data for the sensitized iscmerization of trans-stilbene by BrRe (c0) 3 (3-benzoylpyridine) 2 .a [jg-S] , (M) [g—S] , (M) Area E-S/ Area C18 Area g-S/Area C18 ¢t~+C 0.0081 0.000243 1.634 (0.0038) 0.0487 0.33 0.0102 0.000247 1.622 (0.0047) 0.0373 0.35 0.0203 0.000284 1.589 (0.0095) 0.0214 0.41 0.0406 0.000356 1.592 (0.0135) 0.0135 0.51 0 . 0504 (BP) 0 . 000273 - - - abenzene solvent, 366 nm, [Rebenzpy] = 0.0122 M, [BP] = 1.002 M, go Column D. bNmbers in parenthesis refer to [C18] .