'3 “a, ht. $33154 ggffifiéfiw 3'4". ff 1 )4 EK‘ Wham; 5m f t U9. flhx&uV 'a A ... I",‘"' R5?“ 1! "A" I...‘ . :ut‘...l$'< \ $32.3? . p1! ‘+._J .. ‘ ”WV?" . ‘”‘ 45¢ {-.«.-~~"='"‘~‘:;:‘1 ”A? .3? mwfififl‘k-TL . (- I‘d: annulpol «an: any as u: was, .mazn... K *‘L ‘21 :31 n. "a V3.1? . ~53?“ -A mtg: ' :31. " 1.11 ‘ “‘ mg“ :4 . " I: :‘w E h “m “-13% ‘, NW .- m «an-.39.. an; , H . 1-4 '- «(can A {L J. ,. :) mm. .L- ‘ "My. "WI-Hr'lr w 'r9-l sITY LIBRARIES AAA9AA'A AAAA9A9 AAA A99AA AAA AAA AA9A9AAA l This is to certify that the dissertation entitled PART I PHOTOINDUCED SULFUR-CARBON BOND CLEAVAGE PART II PHOTOCYCLIZATION 0F 0THRO-BENZOYL N-ALKYLANILINIUM IONS presented by Qunjian Cao has been accepted towards fulfillment of the requirements for ph.D. degreein Chemistry 3' ruggrofear Datejac ' AKII/YY/ ' I MS U is an Affirmative Action/Equal Opportunity Institution 0-12771 LIBRARY Mlchlgan State A Unlverslty Puce IN RETURN édxié remcé’é this'éheckout from your record. TO AVOID FINES tetum on or before date due. DATE DUE DATE DUE DATE DUE WWI MSU I. An Affirmative Action/Equal Opportunity Institmion ammo-9.1 PARTI PHOTOINDUCED SULFUR-CARBON BOND CLEAVAGE PART II PHOTOCYCLIZATION OF ORTHO-BENZOYL N-ALKYLANILINIUM IONS By Qunjian Cao A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Chemistry 1990 63‘0- 9693 ABSTRACT PART I PHOTOINDUCED SULFUR-CARBON BOND CLEAVAGE PART II PHOTOCYCLIZATION OF ORTHO-BENZOYL N-ALKYLANILINIUM IONS by Ounjian Cao PARTI The photochemistry of several alkylthiophenyl ketones and alkylthiomethylphenyl ketones has been investigated. Upon irradiation, homolytic sulfur-carbon bond cleavage was observed as a major chemical process. p-(Phenylsulfinyl)methylbenzophenone, p-(phenylsulfonyl)methyl- benzophenone and some corresponding (halomethyl)benzophenones and (halomethyl)acetophenones were also studied to compare the reactions of the corresponding ketones. Maximum quantum yields of the photoreactions were obtained by using thiophenol to trap all radicals that escaped from solvent cages. Triplet lifetimes for all the ketones were determined by Stern-Volmer quenching experiments. lntramolecular charge-transfer to triplet excited carbonyl group from sulfur was observed in o-benzylthiobenzophenone and o-benzylthio- acetophenone. The rate constants of carbon-sulfur bond cleavage were deduced from the triplet lifetimes. The relative rates of substituted p-methyl- benzophenones, which is SOPh ~ Br > SPh > Alkyl-S > Cl > SOzPh, reveal the stabilities of the radicals that are generated from carbon-sulfur bond cleavage. Meta substituted phenyl ketones exhibited much lower rate constants compared to their para analogs. This may be due to a lack of spin density at the meta position compared to the para position in the excited triplet state. PART II The photochemistry of o-benzoyI-N-alkylanilinium salts was investigated. Irradiation of o-benzoyltrimethylanilinium tetrafluoroborate. in acetonitrile solution and in solid state affords 1,1-dimethy|,3-hydroxy-3-phenyl-2,3- dihydroindolium tetrafluoroborate. The quantum yield of the reaction is 0.34. This is in direct contrast to the known inactivity of o-benzoyl-N,N- dimethylaniline. Evidently, a positive charge on the nitrogen changes the nature of the excited state from 3(1r,rr*) to 3(n,1r*). The photoreaction proceeds via intramolecular &hydrogen abstraction by the triplet carbonyl oxygen followed by 1,5-biradical coupling to form the substituted dihydroindole product. The rate constant was evaluated ( k = 6.8 x 107 s") and it appears that, compared to 0+ butylbenzophenone ( k = 109 s"), the positive charge on the nitrogen deactivates the reaction. Similarly, irradiation of o-benzoyl-N,N-dibenzylanilinium chloride yielded, in acetonitrile solution, N-benzyl-2,3-diphenylindole. Interestingly, the quantum yield is only 0.0067, plausibly because an unknown process ( k = 109 s") from triplet excited state decays to the ground state ketone. The photocyclization reaction follows the same mechanism. Stern-Volmer analyses for both systems allowed the calculation of qu values as well as the estimation of the respective lifetimes (15 and 0.24 ns). ACKNOWLEDGMENTS The author wishes to thank Professor Peter J. Wagner for his help, guidance and innumerable entertaining discussions during the course of this work. The author is also grateful to the National Science Foundation and Michigan State University for financial support. Finally, the author wishes to thank all members of Dr. Wagner's group. Their friendship and kindness made the time during this work very pleasant. Table of Contents Chapter List of Tables List of Figures List of Schemes Introduction A. Photophysics of Aromatic Carbonyl Compounds B. 8-Hydrogen Abstraction Reaction and 1,5-Biradicals C. lntramolecular Charge-Transfer Quenching By Sulfur and Nitrogen D. Photoinduced Sulfur-Carbon Bond Cleavage Part I. Photoinduced Sulfur-Carbon Bond Cleavage Results A. Preparations of the Ketones B. Identification of Photoproducts C. Molecular Mechanics Calculations D. Spectroscopy E. Kinetic Results 1. Quantum Yields 2. Triplet Lifetime Discussion A. Mechanism B. Radicals C. Triplet Lifetimes of Ketones Page VIII XIII 1 1 14 21 21 21 24 28 29 29 29 3O 48 48 53 54 D. Reactivities of C-S Bond Cleavage 63 Part II. Photocyclization of Ortho-Benzoyl N-Alkylanilinium Ions ------------- 71 Results 71 A. Preparation and Identification 71 B. Photocyclization and Identification of Photoproducts 73 1. Photoproduct from o-BenzoyltrimethylaniIinium Tetrafluoroborate 73 2. Photoproducts from o-BenzoyI-N,N-dibenzylaniline Hydrochloride 74 3. Irradiations of Some Other Anilium Ions 75 4. Irradiation of o-Benzoyl-N-benzylaniline 75 C. Kinetic Results 75 1. Quantum Yields 75 2. Triplet Lifetime 76 D. X-Ray Crystallography 76 Discussion 86 A. Biradical Process 86 B. Triplet Excited State Lifetimes 88 C. 8-Hydrogen Abstraction Rate Constants 89 D. Nature of the Triplet Excited States 91 E. Effect of water on Quantum Yield 92 F. The Charge Effect 93 G. Suggestions for Further Investigation 94 Experimental 1 00 A. Preparation and Purification of Materials 100 1. Solvents 100 2. Internal Standards 100 VI 3. Quenchers 4. Ketones B. Techniques 1. Photochemical Glassware 2. Sample Preparations 3. Degassing Procedure 4. Irradiation Procedure 5. Analysis Procedure 6. Calculation of Quantum Yield 7. Spectroscopic Measurements C. Isolation and Identification of Photoproducts D Molecular Mechanism Calculations Appendix List of References VII 101 102 125 125 125 125 126 126 127 128 129 141 143 200 List of Tables Table Page 1. Minimized Energies of Different Conformations of p-Alkylthiobenzophenones 31 2. UV Absorption Data for Various Ketones 32 3. Phosphorescence Spectra at 770K in 2-Methyltetrahydrofuran ------ 33 4. Kinetic Data for Various Alkylthiophenylketones 34 5. Kinetic Data for Various Substituted Methylphenyl Ketones in the Presence of 0.05-O.1 M Thiophencl 35 6 Maximum Quantum Yields of Ketones 56 7 Inverse Lifetimes of Ketones 57 8 Kinetic Data for Alkylthiophenyl ketones 61 9 Kinetic Data for Methylphenyl ketones Derivatives 62 10. Relative Rates for C-S Bond Cleavage of Alkylthiobenzophenone-- 63 11 Relative Rates for C-S and C-X Bond Cleavage of p-Methylbenzophenone Derivatives 64 12. Relative Rates for C-S and C-X Bond Cleavage of Methylphenyl Ketone Derivatives 65 13. Relative Minimal Energies for Conformations of Alkyl Thiobenzophenone 68 14. C-S Bond Dissociation Energies 70 15. Ultraviolet and Phosphoresence Spectra of o-Benzoylaniline Derivatives in Methanol 77 VIII 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27 28. 29. Quantum Yields and qu's for Disappearance of o-BenzoyltrimethylaniIinium Tetrafluoroborate upon Irradiation of o-Benzoyltrimethylanilinium Tetrafluoroborate in Acetonitrile solution 77 Quantum Yields and ch's for 1-Benzy|,2,3-diphenylindole from Irradiation of o-BenzoyI-N,N-dibenzylaniline Hydrochloride in Acetonitrile 78 Kinetic Data for o-Benzoyltrimethylanilinium Tetrafluoroborate and o-BenzoyI-N,N-dibenzylaniline Hydrochloride 89 Values of the Response Factors in GC Analysis 144 Values of the Response Factors in HPLC Analysis 145 Quenching of 4,4'-Dithiodibenzophenone Formation upon Irradiation of p-Benzylthiobenzophenone 147 Quantum Yields of Irradiation of p-(Benzylthio)benzophenone -------- 147 Quantum Yields of Irradiation of p-(t-Butylthio)benzophenone --------- 148 Quenching of 4,4'-Dithiodibenzophenone Formation upon Irradiation of p-t-Butylthiobenzophenone 149 Quenching of 4,4’-Dithiodibenzophenone Formation upon Irradiation of p-(sec-Butylthio)benzophenone 150 Quantum Yields of Irradiation of p-(sec-Butyllthio)benzophenone---151 Quenching of 4,4’-Dithiodiacetophenone Formation upon Irradiation of p-(Benzylthio)acetophenone 152 Quantum Yield of Irradiation of p-(Benzylthio)acetophenone in Benzene 152 Quenching of Toluene Formation upon Irradiation of o-(Benzylthio)benzopheno .e 153 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44 Quantum Yields of Irradiation of o-(Benzylthio)benzophenone in Benzene 154 Quenching of Dibenzyl Formation upon Irradiation of o-(Benzylthio)acetophenone at 366nm 155 Quantum Yield of Irradiation of o-(Benzythio)acetophenone- --------- 156 Quantum Yield of Irradiation of o-(Benzythio)acetophenone ----------- 156 Quenching of p—Methylbenzophenone Formation upon Irradiation of p-(Phenylthio)methylbenzophenone 157 Quantum Yields of Irradiation of p-(PhenyIthio)methybenzophenone 158 Quantum Yield of Irradiation of p-(PhenylthioI)methbeenzophenone 158 Effect of Thiophenol Concentration on Quantum Yield of Irradiation of p-(PhenyIthio)methybenzophenone 159 Quantum Yields of Irradiation of p-(t-Butylthio)methylbenzophenone 1 60 Quenching of p-Methylbenzophenone Formation upon Irradiation of p-(t-Butylthio)methylbenzophenone 161 Quantum Yields of Irradiation of p—(sec-Butylthio)methylbenzophenone 1 62 Quenching of p-Methylbenzophenone Formation upon Irradiation of p-(sec-Butylthio)methylbenzophenone 163 Quenching of p-Methylbenzophenone Formation upon Irradiation of p-(n-Butylthio)methylbenzophenone 164 Quantum Yield of Irradiation of p-(n-Butylthio)methylbenzophenone 1 64 Quantum Yield of Irradiation of p-Bromomethylbenzophenone ----- 165 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. Quenching of p-Methylbenzophenone Formation upon Irradiation of p-ChIoromethylbenzophenone 166 Quantum Yield of Irradiation of p-ChIoromethylbenzophenone ----- 167 Quantum Yield of Irradiation of p-(PhenylsuIfinyl)methylbenzophenone 168 Quenching of p-Methylbenzophenone Formation upon Irradiation of p-(PhenyIsquonyI)methylbenzophenone ----------- 169 Quantum Yield of Irradiation of p-(Phenylsulfonyl)methylbenzophenone 170 Effect of Thiophenol Concentration on Quantum Yield of Irradiation of p-(Phenylthio)methyacetophenone 171 Quenching of p-MethyI Acetophenone Formation upon Irradiation of p-(Phenylthio)methylacetophenone 172 Quantum Yield of Irradiation of p-(Phenylthio)methylacetophenone-172 Quenching of p-Methyl acetophenone Formation upon Irradiation of p-Bromomethylacetophenone 173 Quantum Yield of Irradiation of p-Bromomethylacetophenone ------ 174 Quantum Yields of Irradiation of m-(Phenylthio)methylbenzophenone 175 Quenching of m-Methylbenzophenone Formation upon Irradiation of m-(Phenylthio)methylbenzophenone 176 Quantum Yields of Irradiation of m-ChIoroxymethylbenzophenone 1 77 Quenching of m-Methylbenzophenone Formation upon Irradiation of m-ChIoromethylbenzophenone 178 Quantum Yields of Irradiation of m-(Phenylthio)methylacetophenone 179 XI 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70 71 72. Quenching of m-Methylacetophenone Formation upon Irradiation of m-(PhenyIthio)methylacetophenone Quantum Yield of Irradiation of o-BenzoyI-N,N-dibenzylaniline Hydrochloride Effct of Water on Quantum Yield for Irradiation of o-BenzoyI-N,N-dibenzylaniline Hydrochloride _ Quenching of N-benzyl-2,3—diphenylindole Formation upon Irradiation of o-BenzoyI-N,N-dibenzylaniline Hydrochloride--- Quenching of N-BenzyI-2,3-diphenylindole Formation upon Irradiation of o-BenzoyI-N,N-dibenzylaniline Hydrochloride in 8% Aqueous Acetonitrile Solution Quenching of N-BenzyI-2,3-Diphenylindole Formation upon Irradiation of o-Benzoyl-N,N-dibenzylaniline Hydrochloride in 4% Aqueous Acetonitrile Solution by Sodium Sobate Quenching of N-BenzyI-2,3-diphenylindole Formation upon Irradiation of o-BenzoyI-N,N-dibenzylaniline Hydrochloride in 8% Aqueous Acetonitrile Solution by Ethyl Sobate Quenching of N-BenzyI-2,3-diphenylindole Formation upon Irradiation of o-BenzoyI-N,N-dibenzylaniline Hydrochloride in 8% Aqueous Acetonitrile Solution by 1-Naphthylethylamine Hydrochloride Stern-volmer Analysis of o-BenzoyltrimethylaniIinium Tetrafluroborate in Acetonitrile solution Stern-volmer Analysis of o-BenzoyltrimethylaniIinium Tetrafluroborate in Acetonitrile Solution Torsion Angles for N-benzyI-2,3-diphenylindole Bond Angles for N-benzyI-2,3-diphenylindole Bond Distances for N-benzyI-2,3-diphenylindole XII 180 181 181 182 183 184 185 186 187 188 189 191 193 List of Figures Figure P399 1. Quantum Yields of Irradiation of p-(PhenyIthio)methylbenzophenone and p-(Phenyithio)methylacetophenone vs. the Concentrations of Thiophencl 36 2. Stern-Volmer Plot of o-(Benzylthio)acetophenone with 1-Methylnaphthalene and of o-(Benzylthio)benzophenone with Naphthalene in Benzene Solution 37 3. Stern-Volmer Plot of p-(Phenylthio)methylacetophenone and of p-(Phenylthio)methylbenzophenone with Naphthalene in Benzene Solution 38 4. Stern-Volmer Plot of p-(n-Butylthio)methylbenzophenone, p-(sec-Butylthio)methylbenzophenone and p-(t-Butylthio)methylbenzophenone by Naphthalene in Benzene Solution 39 5. Stern-Volmer Plot of p-(Benzylthio)acetophenone with 1-Methylnaphethalene and of p-(Benzylthio)benzophenone by Naphthalene in Benzene Solution 40 6. Stern-Volmer Plot of p-(t-Butylthio)benzophenone with Naphthalene in Benzene Solution 41 7. Stern-Volmer Plot of p-(sec-Butylthio)benzophenone with Naphthalene in Benzene Solution 42 XIII 10. 11. 12. 13. 14. 15. 16. 17. 18 19 20 Stern-Volmer Plot of p-ChIoromethylbenzophenone with Naphthalene in Benzene Solution Stern-Volmer Plot of p-PhenylsuIfonylmethylbenzophenone with Naphthalene in Benzene Solution Stern-Volmer Plot of m-(Phenylthio)methy|acetophenone with Naphthalene in Benzene Solution Stern-Volmer Plot of m-(Phenylthio)methylbenzophenone with Naphthalene in Benzene Solution Stern-Volmer Plot of m-ChIoromethylbenzophenone with Naphthalene in Benzene Solution Stern-Volmer Plot of o-BenzoyI-N,N-dibenzylaniline Hydrochloride with Ethyl Sorbate in Aqueous Acetonitrile Solution Stern-Volmer Plot o-BenzoyI-N,N-dibenzylaniline Hydrochloride with Sodium Sorbate in 4 % and 8% Aqueous Acetonitrile Solution Effect of Water in Acetonitrile Solution on Quantum Yield of o-BenzoyI-N,N-dibenzylaniline Hydrochloride and Quantum Yield N-Benzyl-2,3-diphenylindole upon Irradiation of o-Benzoyl-N,N-dibenzyIaniIine Hydrochloride Stern-Volmer Plot of o-benzoyltrimethylanilinium Tetrafluroborate with Ethyl Sorbate in Acetonitrile Monitored by UV at 340 nm -------- Stern-Volmer Plot of o-benzoyltrimethylanilinium Tetrafluroborate with 2,4-hexadiene in Acetonitrile Monitored by IR at 1674.5-1664.5 cm-1 X-ray Structure of N-benzyl,2,3-diphenylindole UV Spectra of 0.002029 M o-Benzylaniline Hydrochloride ------------ UV Spectra of 0.0017 M o-BenzoyI-N,N-dibenzylaniline XIV 43 44 45 46 47 79 80 81 82 83 84 85 85 List of Schemes Scheme Page 1. Modified Jablonski Diagram for an Excited Ketone 2 2. Mechanism of SC bond cleavage of ketosulfides 52 3. Available Hydrogen Abstraction Pathway for o-Benzoyl N-Alkylanilinium tetrafluoroborate 86 Available Hydrogen Abstraction Pathway for o-BenzoyI-N,N-dibenzylaniIine Hydrochloride -- 87 Phosphoresence Spectra for m-MeAP, m-MeBP, m-PhSCHzAP and m-PhSCHzBP in 2-MethyItetrahydrofuran 195 Phosphoresence Spectra for p-BzSBP, p-t-BuSBP, p—sec-BuSBP and p-n-BuSBP in 2-Methyltetrahydrofuran 196 Phosphoresence Spectra for p-PhSCHzBP, p-CICHzBP, p-t-BuSCHzBP and p-n-BuSCHzBP in 2-Methyltetrahydrofuran ----- 197 Phosphoresence Spectra for p-BzSAP, o-BzSAP, o-BzSBP and p-PhSCHgAP in 2-MethyItetrahydrofuran 198 Phosphoresence Spectra for o-BzzNBPzHCI, o-BzzNBP and o-Me3NBPzBF4 in MeOH lEtOl-l 199 XV INTRODUCTION EEIII'IE I'GIIC | The photochemistry of carbonyl compounds is one of the most active and fundamental fields of research in organic photochemistry. The carbonyl chromophore, especially the aromatic carbonyl chromophore, can be excited by absorption of photons in near ultraviolet light to give products that can be easily isolated and analyzed. A wide variety of photophysical and photochemical reactions can occur via the excited state of the aromatic carbonyl. Hence, it provides a very useful tool in systematic studies of both synthetic and mechanistic organic photochemistry. To understand carbonyl photochemistry, it is necessary to know the photophysics of the excited state which is described with a modified Jablonski diagram in Scheme 1.1 Absorption of light by a carbonyl compound promotes a molecule from singlet ground state (So) to the singlet excited state (Sn). Internal conversion from Sn to S1 is very efficient and we only need to consider the S1 state.2 The excited S1 state molecule can decay to the ground state molecule by emission of light (kf) or by radiationless transition (kd) to ground state. The half occupied molecular orbitals in S1 have paired electron spins. However , the more stable electronic configuration is the one having unpaired hv k, kd kd kp products products ,0 l . l Scheme 1. Modified Jablonski Diagram for an Excited Ketone. spins. Thus, the excited singlet state S1 can undergo intersystem crossing to an triplet excited state (Tn). The rate constant of intersystem crossing (kisc) for benzophenone is about 1011 S'1 and it is believed that this is the case for most of simple phenyl ketones.4»5 Since the rate constants of intersystem crossing of phenyl ketones ( kisc ~ 1011 5'1 ) are so large, compared to rate constants of fluorescence ( k1 ~ 105-109 5'1 ) and rate constants of nonradiative decay ( kd ~ 105-108 S'1 ), we need only consider the lowest triplet excited state (T1 ).2v6 The excited triplet state can also decay via phosphorescence ( kp ~ 101- 104 S‘1 ) and the low rate of the T1 to So transition is caused by its spin- forbiddenness.3 However, radiationless decay from the excited triplet state to ground state is also possible. In addition, singlet and triplet excited states can undergo chemical reactions to products. It ought to be mentioned that direct transitions from So to T1 are also spin-forbidden and can be ignored for low intensity excitation. There are two different types of triplet excitation of the aromatic carbonyl compounds with quite different physical and chemistry properties. An n,n* triplet excitation transfers an electron into a u' antibonding orbital from the carbonyl nonbonding orbital and results in an electron poor oxygen. This deficiency gives an n.1t" triplet excited state a chemical behavior similar to that of an alkoxy radical.7 Reactions arising from the n,1r* triplet excited state are those expected from the alkoxy radical. A 1r,1r* triplet excited state is the one in which a 1: orbital electron is promoted into a n‘ antibonding orbital and results in a shift of electron density from the aromatic n-system to the carbonyl oxygen, producing an electron rich oxygen. The 1r,1t* triplet excited state is less reactive to radical reactions at the carbonyl oxygen than is the me“ triplet excited state. R 3inst“) <:>—<° CH” <:>=<°' 3(1wt‘) Phenyl ketones have 1r,1t* triplet energies very close to those of n,n* triplets. Substituents on the benzene ring of phenyl ketones stabilize or destabilize the the two excited states in different way and therefore determine which triplet excited state is the lowest. Usually, electron withdrawing groups stabilize the n,1r* transition and electron donating groups stabilize 1r,1r* transition. The polarity of different solvents also has an effect on the relative triplet energy of the two levels. Thermal equilibrium of the two triplets can be reached if the two triplet state are close to each other within a few kcals and as a result, ketones with a 1t,1t* lowest triplet can undergo hydrogen abstraction from the n,n* triplet excited state with low efficiency.6 A mixture of the two triplets is also possible if the two excited state are close enough.8 Bfi-lll III I' B l' IIE-B' I' I Photoexcited ketones undergo characteristic hydrogen abstraction from suitable donors having reactive hydrogens. This reaction was first reported by Ciamician and Silber in 1900.9 Excited benzophenone abstracts hydrogen from ethanol to generate benzophenone ketyl radicals. Benzpinacol is formed by coupling of radicals. OH ‘CO CH3CHZOH’ ”C —_7 P“ (1] i Ph Ph Ph Hydrogen abstraction can also occur from a position within the ketone molecule. lntramolecular hydrogen abstraction was first observed by Norrish.10 This reaction is known as the Norrish II reaction, which involves formation of a 1,4-biradical11 via abstraction of a y-hydrogen by the excited carbonyl oxygen. The biradical can either cleave into a smaller ketone and an olefin, or cyclize to cyclobutanol:1 2 O “V OH Ph U ———> - - —- Ph H‘U CH / OH 3 >= + \= HO Ph The reactivity for internal hydrogen abstraction depends largely on the nature and multiplicities of the excited state. It has been well accepted that hydrogen abstraction occurs more efficiently from n,1r* excited ketones.7 The radical-like oxygen of an n,1c* excited ketone behaves in the same way as an alkoxy radical. Ring substituents that lower the 1r,1t* excited state energies will decrease the reactivity of the reaction. In an unconstrained system, an excited ketone shows a preference for abstraction from the y—position. It was believed that the reaction proceeds via a six-membered cyclic intermediate.13 Later studies showed that 8-hydrogen abstraction is competitive with y-hydrogen abstraction in a system with activated 8-hydrogen and inactive y—hydrogens.” Both entropy and enthalpy factors determine the ratio of the formation of 1,4-biradical and 1,5-biradical. The preference for 1,4-biradical formation over 1,5-biradical formation is because of the lower entropy for forming a smaller six-membered transition state in y-hydrogen abstraction. Introducing substituents on the 8-carbon may change the y/ 6-hydrogen abstraction ratio but cannot prevent the formation of a 1,4-biradical because of a strong entropy effect. Therefore, to study 8-hydrogen abstraction, systems with no y-hydrogen have to be used. Reactions of acyclic B-alkoxy ketones were reported.15'25 The biradicals generated from 8-hydrogen abstraction undergo cyclization to cis- and trans- cyclopentanols and disproportionation to enol of the starting ketone, which was confirmed by isotope experiments. Solvents strongly influence the distribution of the products and influence the cis/trans ratio of the cyclization products. A nonpolar solvent such as benzene favors the product with methyl group trans to phenyl group (E) and polar solvents such as t-BuOH favor the product with methyl group cis to phenyl group (2)115 L . H “9 : hv OH o —> O —> . + ‘6‘ O U benzene ' Ph‘“ 0 P” Ph Z Ph l E MD __, 0 Lo \ ,h/v Ph The photochemistry of a-(o-tolyl)ketones were investigated.16 Three competing reactions were found. They were 8-hydrogen abstraction followed by cyclization, a-cleavage and 1,3-aryl migration: \ 11: I \ . OH OH I// // . Q. R 2 2 1 R2 1 R R1 — R2\ / 0 \ / # R1CHO The photocyclyzation of o-benzyloxybenzaldehyde was reported by Pappas.17 Z and E-2-phenyI-3-hydroxy-2,3-dihydrobenzofuran were obtained.18 Photolysis of several methyl o-aryloxyphenyl glyoxylates also gave Z and E 3-hydroxy-2,3-dihydrobenzofurans.19 Dependency of stereoselectivity )Ph :h :h 0 o 0 .6” hv o" R ———> OH O + R = HorCOzMe 2 E on temperature and solvents was investigated. The Z isomer with the phenyl and carbomethoxy groups trans to each other are more favored at low temperatures than at higher temperatures and preferred more in the nonpolar solvent than in the polar solvent. Lappin reported20 the photolysis of 2-benzyloxy-4-dodecyloxy- benzophenone. The reaction gave 6-dodecyloxy-2,3-dihydro-2,3-diphenyl-3- 8 benzofuranol as product. The triplet n,1c* excited state was believed to be involved in the process and the lifetime of the excited state was measured (30 ns). jh jh Ph 0 hv 0 ' O O ____’ OH ___> OH 0 Ph D Ph [g Ph R0 no RO R = 012H25 Wagner and Meador21 studied the photochemistry of o-alkoxyphenyl ketones which undergo photocyclization to benzodihydrofuranols via 6- hydrogen abstraction: O I R20 I"l2 . (ll; IN 0) O OH 9 The rate constants of o-methoxybenzophenone (5 x 105 s"), 2,6- diacylmethoxybenzene (1 x 107 s"), o-benzyloxybenzophenone (2 x 107 s") and 2,6-dimethoxybenzophenone (2 x 105 s") were measured. The low rate constants for 8-hydrogen abstraction are caused by conformational factors, especially by an equilibrium between syn and anti rotamers of the o-alkoxy group. The rate difference between o-methoxybenzophenone and o- benzylbenzophenone indicates that C-H bond strengths are also important. The relatively low rate constant of 2,6-dimethoxybenzophenone shows that the triplets reach rotational equilibrium about the benzene-carbonyl bond before reaction. 0 1| 0 (II) 0* 0” A r C o w 0 a 0 ., anti syn The lower rate constants of o-methoxyacetophenone ( <105) and o- benzyloxyactophenone ( 2 x 106 S'1 ) relative to the corresponding benzophenone derivatives reflect the low reactivity of 1m" lowest triplets in hydrogen abstraction.22 O’Connell23 reported that photolysis of 2,4-di-tert-butyl-6-methoxy- benzophenone gave a cycloaddition product that is a 3,3-dimethyl-1-indanol derivative. This result indicated that 8-hydrogen abstraction from the tert-butyl group was much faster than that from methoxy group. 10 hv Wagner and Scaian024 reported the rate constant for 6-hydrogen abstraction in 2-t-butylbenzophenone (k = 109 ). X-ray analysis indicated that this fast 8-hydrogen abstraction was due to a suitable conformation with tert- butylphenyl ring twisted 69° from coplanarity with the carbonyl which holds tert- butyl hydrogens within the bonding distance of the oxygen: hv Aoyama25 reported the photolysis of 2-dimethylamino-benzophenone. O N(CHa)2 COPh O O Lg /Q * ‘NHCH, 11 1-MethyI-3-phenylindole was obtained in a very low yield together with 2- methylaminobenzophenone. This low yield is expected because the lowest triplet excited state is 1c,1r* and is because of conformational restriction. lntramolecular charge-transfer quenching by nitrogen atom also accounts for the low yield. O . O I .“o: . l..:- .1 : O :1... . .10 L 00:. Photochemical charge—transfer reaction was first observed by Cohen26 in the photoreduction of benzophenone. The reduction is 1000 times faster by Et3N than by isopropanol. The mechanism was suggested to involve a rapid electron transfer from nitrogen to the triplet excited carbonyl followed by a proton shift. .. . a... 3(RZC=O)* + RCH2NR2——> 3(RZC-O' RZNCHZRV = RZCOH + RCHNR2 Wagner27 studied the quenching of triplet valerophenone by triethylamine and dimethyl tert-butylamine. Both amines quench the triplet state with the same rate constant and no difference was observed for the rate constants in benzene and acetonitrile. On the other hand, the rate constants in 12 benzene and acetonitrile are 10 times faster than in methanol. The facts indicated that a charge transfer complex was involved rather than radical ions. Wagner, Kemppainen and Jellinek investigated the intramolecular charge-transfer quenching of a-dimethylaminoacetophenone, y- dimethylaminobutyrophenone and 8-pyrrolidinovalerophenone.27 The results 0 O CSHSgCHZNMBZ C6H5£CH20H20H2NM92 O CGHSECHZCHZCHZCHZNO indicated that tertiary amines can quench singlet excited states of phenyl ketones although the rate constants of intersystem crossing for phenyl ketones are very high (kisc ~ 1011 s"). The singlet quenching efficiency decreased as the distance of the amino substituent increased. Charge transfer complexes are also involved in the triplet excited state of y- and 8-aminoketones and the rate constants for intermolecular quenching also decreased as the distance increased. The charge transfer complexes formed from y- and 8-aminoketones cannot form biradicals by hydrogen abstraction because of the conformational restrictions that results in low quantum yields for type II reaction (0.046 for 6- pyrrolidinovalerophenone and 0.015 for y—dimethylaminobutyrophenone in benzene). The slow formation of the triplet charge-transfer complex of or- aminoketone is caused by conformational factors for approach of the lone pair on nitrogen to the oxygen. The high efficiency of type II products for the 13 hydrochloride salt of the 8-aminoketone(0.38 compared to 0.08 for 8-amino ketone) indicates the absence of competing charge transfer quenching from both singlet and triplet excited states. The large kqt values for the hydrochloride salts of 5- and y-aminoketones(570 and 720 compared to 33 and 4.5 for free amino ketone) reflect the lack of competing charge transfer quenching from triplet excited states and very slow H-abstraction. Other heteroatoms such as sulfur, phosphorous, antimony and arsenic can also form C-T complexes with excited carbonyl groups.28 Wagner and Lindstrom investigated a—, [3- , y—, 8- and 6-phenacyl sulfides, sulfoxides and sulfones.29 They found that the rate constants for charge-transfer (kc‘r) are maximum for n = 2 and decrease for n > 3. Since the C-T quenching O O O 1311940112158 Ph&(CH2),,SOR Phg(CH2),,SOZR R = n-butyl, thflYl n = 1, 2, 3, 4, 5 is a through-space process and controlled by conformational factors, five or six atom cycles are the most favorable. SR is a better quencher than NR2 for n = 1 - 3 is because of the longer reach of sulfur 3p orbital compared to a nitrogen sp3 orbital. The rate constants km for intramolecular quenching of PhCO(CH2)n- SBu are 160, 550, 290, 17, <2 ( x 107 s-1)1or n = 1, 2, 3, 4, 5 respectively. 14 The photoinduced homolytic cleavage of carbon-sulfur bonds is of interest to a wide range of physical and organic chemists. Compounds which undergo photochemically-induced carbon-sulfur bond cleavage are useful as synthetic intermediates30 and as initiators for free radical polymerization.31 Photolysis of sulfides, sulfoxides and sulfones results in the production of radical species via homolytic cleavage of the carbon-sulfur bond. These free radicals have been studied with physical methods, such as CIDNP32, EPR,33 and flash photolysis34 as well as with chemical methods. Haines35 first reported the decomposition of simple alkylsufides upon irradiation at 254 nm for 65 hours. H2 and saturated hydrocarbon related to the alkyl on the sulfur were found. Later, Milligan36 found CH4, CzHe and CH3$SCH3 by irradiation of methylsulfide in gas phase. Callear and Dickson34 established that the carbon-sulfur bond cleavage was the primary process which generated methyl and methylthiyl radical by using flash photolysis at 195 nm: R'SR hV : IE" + SR Adam and Elliot33 investigated the photolysis of several simple alkyl sulfides at 254 nm in dilute glasses of 3-methylpentane. The radical pairs that hv . - EtSEt > EtS + Et h (CHaCHchzlzs ——-V——-> CH30H20H2' + -SCHZCHZCH3 15 reacted with each other gave rise to the main diamagnetic products . Knight37 reported the photolysis of simple alkyl sulfides in the gas phase using 229 nm Iightor sensitization by triplet mercury.38 Quantum yields were pressure dependent. In the case of methy Iethyl sulfide, the products of photolysis are Csz, CH3$SC2H5, 02H5$SC2H5, CH4, CH3$CH3, C2H5SC2H5, C3H3, CzH4, C2H5SH and CH3$H.37 All of the products are formed from radical recombination, hydrogen abstraction and radical disproportionation. Quantum yields for decomposition of methyl sulfide, methylethyl sulfide and ethyl sulfide at 254 nm were also determined (0.51, 0.46 and 0.49 respectively).38 The nature of the C-S a-cleavage in photochemical reactions of sulfoxides has been studied in detail with the CIDNP technique by Muszkat.32 In the photoreactive ortho-substituted phenyl methyl sulfoxides, the triplet spin H CH4* T=- esca e CH3 CH CH * ArSOCHa ——-hv 3(ArSO+CH3) p RS 3 3 =- RSCH3* T=- recombining II ArSOCHa T(CH3) = + correlated methyl- arylsulfinyl radical pair, CH3 + ArSO, was formed and detected by CIDNP method. The photochemical behavior of some methyl vinyl sulfoxides such as cyclopent-1-enyl sulfoxide and cyclohex-1-enyl sulfoxide were similar to that of the ortho-substituted methyl phenyl sulfoxides.32 16 O 3 0 ‘ SC5H5CH3 hV SC 6HSCH 3 8:0 8:0 CH! - .1. CH3 Photolysis of methyl B-substituted ethyl sulfoxide caused sulfur-carbon bond cleavage only at the ethyl-sulfinyl bond.32 0 CH-OSECHZCHZSICH3—L _’3(CH3—OSECHZCH2+ flow) 0 ’/o &* * ll CHa—OS CHZCHZSCHs In 1956, Schonberg39 reported photochemical reactions of desoxybenzoin derivatives in sunlight. Didesyl cystal was obtained in each reaction from sulfur-carbon bond cleavage followed by radical coupling reaction. 17 0 o sunfight , . CsHsgCHSR ——> csHsgcle + SR C6"‘I5 / CsHS (CGHSCOHC6H5)2 R = CeHs, o-CeH4CH3, m-CeH4CH3, p-CeH4CH3. COCeHs Hill40 et al described the photoprocesses of aryl phenacyl sulfides and benzyl phenacyl sulfides and related ketosulfides. The products obtained are generated from carbon-sulfur bond cleavage. The C-S bond cleavage may be 0 0 “SR hv > (RS)2 + ‘Kmr 600%th x . x a; x = H, R = p-tolyl b; x = H, R = 2,4,6-Me306H2 c; x = Cl, R = p-tonI d; x = OH, R = p-tolyl f; x = OMe, R = p-tolyl g; x = Ph, R = p-tolyl h; x = H, R = benzothiazol-2—yl j; x = H, R = PhCO k; x = H, R =803Na I; x = H, R = PhCOCHgS m; x =CI, R = PhCHg n; x = OH, R = PhCHg p; X = 0M9, R = PhCH2 direct in the case that there is no active y—hydrogen available in those molecules or may happen via y—hydrogen abstraction as in the case of compounds m, n and p. 18 Caserio“1 reported the the photolysis of B-keto sulfides with y-hydrogen. Labelling experiments proved that C-S bond cleavage ocoured via intramolecular hydrogen abstraction. Photolysis of phenacyl alkyl sulfides in deuterochloroform did not give the deuterated acetophenone product, a result that excluded primary C-S bond homolytic cleavage. R! h 0* R” 06H5COCHZSCHR'R" V : Y" 8 Ph RI ~ R" Ph 0H 0 Mr ~ “Y + if k 7 "—7 Ph Ph ' S S R' = R" = H R' = CH3, R" = C6H5 R' = CH3, R" = H Padwa42 investigated the photolysis of a-benzylthioacetophenone and a-benzylthio-4-acetylbiphenyl. The quantum yield of acetophenone product and 1/‘t for a-benzylthioacetophenone in benzene were reported as 0.35 and 7 x 109 $4, respectively. For a-benzylthio-4-acetylbiphenyl, the values are 0.04 and > 1010 s". The difference reflects the different natures of the triplet excited states of the two B-keto sulfides. a-Benzylthioacetophenone has a lowest n,1r* 19 triplet excited state and a-benzylthio-4-acetylbiphenyl has a lowest 1r,1r* triplet excited state. The low quantum yield and short lifetime (1) of a-benzylthio-4- acetylbiphenyl suggest the formation of a charge transfer complex which generates the starting ketone with a rate much faster than hydrogen abstraction. More detailed work on phenyl ketosulfides has been done by Wagner and Lindstrom43. Phenyl ketones have two different low lying triplets, n, n' and 1t, 11'. Absorption and phosphorescence spectra indicate that the n, n’ and 1:, 1? transitions both involve some population of the C-S o"r orbital. This mixing, together with the free spin density on the excited carbonyl carbon, appeared to determine the rate constant for cleavage. The photochemistry of ketones of the structures PhCOCHgSR, PhCOCHgSOR, PhCOCHgSOgR, and p-X-PhCOCHgSPh gave primarily OH kr (13 0 ——>Ph. CHZSQRZ ———> Ph&CH3 + S=CR2 O 05. + PhOCHZSCHRZ kcr: pthstCan \ ground state ketone k 0 / .1. PhOCHz + 9:0an l O O Ph&CH3 + S=CR2 + (Ph80H2)2 + (SCHR2)2 20 acetophenone when irradiated in the presence of thiophenol. According to related work,43 ketosulfides in general undergo two competitive intramolecular triplet reactions: CT quenching and y-hydrogen abstraction. These B-ketosulfides undergo B—cleavage only to the extent that its rate competes with those of the other two reactions. Kinetic studies of B-cleavage reactions of ketones have been done. Oxidation of the sulfur decreased both ky and kCT- However, the RS(O) radical was eliminated much more rapidly than either RS or RSOg, such that B- cleavage becomes a dominant reaction for the ketosulfoxides and a major reaction for the ketosulfones. a-Alkyl substitution resulted in sharp increase of the yield of phenyl ketone which indicates that the more substituted a-keto radicals undergo more disproportionation. 21 PART I. PHOTOINDUCED SULFUR-CARBON BOND CLEAVAGE AND PHOTOGENERATED SULFUR RADICALS Results WWW Substituted alkylthiophenylketones were prepared44 by Sn2 reaction of R NaC ‘ / I + RZSH 2 03 > R1 / \ \X \\| 362 R1 = CH3, R2 = CH2Ph, ortho, o-(benzylthio)acetophenone (o-BzSAP) R1 = CH3, R2 = CH2Ph, para, p-(benzylthio)acetophenone (p-BzSAP) R1 = CH3, R2 = n-octyl, ortho, o-(octylthio)acetophenone (o-CBSAP) R1 = Ph, R2 = CH2Ph, ortho, o-(benzylthio)benzophenone (o-BzSBP) R1 = Ph, R2 = CH2Ph, para, p-(benzylthio)benzophenone (p-BzSBP) R1 = Ph, R2 = n-Bu, para, p-(n-butylthio)benzophenone (p-n-BuSBP) R1= Ph, R2 = t-Bu, para, p-(t-butylthio)benzophenone (p-t-BuSBP) R1 = Ph, R2 = sec-Bu, para, p-(sec-butylthio)benzophenone (p-sec-BuSBP) 22 the corresponding halophenyl ketones with alkyl mercaptan in the presence of sodium carbonate or potassium hydroxide. o-(Methylthio)benzophenone (o-MeSBP) was prepared45 by the methylation of o-mercaptobenzoic acid with dimethyl sulfate and then treated with thionyl chloride followed by Friedel-Crafts acylation of benzene: OOH OOH + (CH3) 2804 /NaOH H3O SOClz : ———->- ———> H CH3 OCl 9 CH3 AlCl3/PhH¥ C 0 o-MeSBP Bromomethylphenyl ketones were prepared by bromination of the corresponding tolyl ketones with NBS: 9 o C NBS/CCI ' R/ I \\ 4 =: If}: I \\ \ . CH3 \CHZBr R = CH3, para, p-bromomethylacetophenone (p-BrCHgAP) R = Ph, para, p-bromomethylbenzophenone (p-BrCHzBP) R = Ph, meta, m-bromomethylbenzophenone (m-BrCHzBP) R = CH3, meta, m-bromomethylacetophenone (m-BrCHgAP) 23 Chloromethylphenyl ketones were prepared by chlorination of the corresponding tolyl ketones with sulfuryl chloride: (,3 o I C so Cl CCI R, I \ 2 2’ ; R’CI \ X . CH3 \CH2CI R = Ph, para, p-chloromethylbenzophenone (p-ClCHgBP) R = CH3, mata, m-chloromethylacetophenone (m-CICH2AP) para-(Phenylsulfinyl)methylbenzophenone (p-PhSOCHgBP) was prepared by oxidation of the ketosulfide in acetone.with excess 30% aqueous hydrogen peroxide: 0 O l C I , H O lacetone ,C Ph 2 2 = Ph 0 SPh Ph Alkylthiomethylacetophenones and alkylthiomethylbenzophenones were prepared by nucleophilic substitution reactions of the corresponding 24 bromomethyI-phenyl ketones with the appropriate mercaptan in the presence of sodium carbonate: R’C \ HSRflNflzCO: RIC I x R1 CH28r R = CH3, R1 = Ph, para, p-(phenylthio)methylacetophenone (p-PhSCHgAP) R = Ph, R1 = Ph, para, p-(phenylthio)methylbenzophenone (p-PhSCHgBP) R = Ph, R1= n-butyl, para,p-(n-butylthio)methylbenzophenone (p-n-BuSCHgBP) R = Ph, R1 = Ph, mata, m-(phenylthio)methylbenzophenone (m-PhSCHgBP) R = CH3, R1 = Ph, mata, m-(phenylthio)methylacetophenone (m-PhSCHgAP) R = Ph, R1 = t-butyl, para, p-(t-butylthio)methylbenzophenone (p-t-BuSCHgBP) R = Ph, R1 = sec-butyl, para, p-(sec-butylthio)methylbenzophenone (p-sec- BuSCHQBP) para-(Phenylsulfonyl)methylbenzophenone (p-PhSOzCHzBP) was prepared by oxidation of the ketosulfide in acetic acid with excess 30% aqueous hydrogen peroxide: 0 O I I C C , H O /acetic acid , Ph 2 2 : Ph ("3 SPh SPh be an. sal 25 Ell IT I' IEII || Irradiation of 0.1-0.2 g of p-BzSBP, p-BzSAP and o-BzSAP in 50 ml benzene afforded a mixture of C-S bond cleavage products: toluene, bibenzyl and disulfides. The disulfide products were separated by silica gel column chromatography with hexane and ethyl acetate as eluent. Their structures were confirmed based on NMR, IR, and Mass spectrometry. Bibenzyl was identified by GC retention time in comparison with commercially available authentic samples: hv I}SCH2Ph'—T PhCH20H2Ph + R = Ph, para position, 4,4'-(dithio)dibenzophenone (p-BPS)2 R = CH3, para position, 4,4’-(dithio)diacetophenone (p-APS)2 R = CH3, ortho position, 2,2’-(dithio)diacetophenone (o-APS)2 Irradiation of 0.2 g of o-BzSBP in 50 ml benzene with a Pyrex filter until 0 Sr“. hv, Pyrex O \ O o = O O S o-BzSBP thioxanthen-9-one 26 100% conversion afforded a product that was isolated on silica gel column with hexane and ethyl acetate as eluent. The structure was identified by NMR, IR and Mass spectra as thioxanthen-9-one. The product could not be detected by GO in experiments run to under 10% conversion. Irradiation of 0.1-0.2 g o-BzSBP or o-BzSAP in 50 ml benzene in the presence of 0.1 M thiophenol afforded a mixture of C-S bond cleavage products, namely toluene and o-mercaptobenzophenone(o-HSBP) or o- mercaptoacetophenone(o-HSAP). Both o-HSBP and o-HSAP were separated by silica gel chromatography using hexane and ethyl acetate as eluent. The structures of mercaptans were confirmed by NMR, IR and Mass spectrometry and toluene was identified by comparing its retention time with authentic sample. ——I> PhCH3 + HSF’h O-BZSBP o-HSBP o-BzSAP o-HSAP Irradiation of p-t-BuSBP and p-sec-BuSBP at 313 nm or 366 nm gave (p- BPS)2 as product. The products were identified by HPLC retention time using authentic sample. hv Ph II Ph \ l/—S 2 SR p-t-BuSBP (p-BPS)2 p—sec-BuSBP 27 Irradiation of p-PhSCH2BP, p-BuSCH2BP, p-BrCH2BP, p-CICH2BP, p- PhSOCH2BP, p-PhSO2CH2BP, p-t-BuSCH2BP and p-sec-BuSCH2BP in the presence of 0.05-0.1 M thiophenol at 313 nm or 366 nm gave as products p- methylbenzophenone (p-MeBP) and phenyldisulfide (PhSSPh). The products were identified by GC using commercially available authentic samples. Irradiations of p-PhSCH2AP and p-BrCH2AP in the presence of 0.05 - 0.1 M thiophenol at 313 nm or 366 nm gave as products p-methylacetophenone (p-MeAP) and PhSSPh. The products were identified by GC using commercially available authentic samples. Irradiation of m-PhSCH2BP and m-CICH2BP in the presence of 0.05-0.1 M thiophenol at 313 nm or 366 nm gave as products m-methylbenzophenone (m-MeBP) and PhSSPh. The products were identified by (30 using commercially available authentic samples. Irradiation of m-PhSCH2AP in the presence of 0.05-0.1 M thiophenol at 313 nm or 366 nm gave as products m-methylacetophenone (m-MeAP) and PhSSPh. The products were identified by (30 using commercially available authentic samples: O o \ by R | = R \ + PhSSPh X HSPh I K CHz-X CH3 R= CH3,Ph X = PhS, Cl, Br, t-Bu, n-Bu, Sec-Bu, SOPh, SO2Ph 28 Irradiations of o-MeSBP, o-C3SAP or p-n-BuSBP in the presence of thiophenol, for more then 48 hours, gave no significant products. CIII IIII . CIII' A molecular modeling software, PCMODEL, distributed by Serena Software, Box 3076, Bloomington, IN 47402-3076, was used to calculate the minimum energy of different conformations of molecules. The MMX force field is used in this program which is derived from the MM2 1987 force field. The energies listed in Table 1 are the total energies of special conformations of the molecules. The total energy is the sum of the 11 system, bond stretching, bond bending, torsional, and non-bonding interaction energies. The energies of different conformations of p-t-BuSBP, p-sec-BuSBP, p-n- BuSBP and p-BzSBP were calculated using the dihedral drive method. For the comformation in Table 1, the solid line is a benzene ring: the sulfur atom attached on the benzene is toward us and a is the dihedral angle between RS and the benzene ring. Minimum energies were calculated for every 15° from a = o to 360° (Table 1). W The UV absorption spectra were recorded for all the ketones. The wavelengths of the absorption maxima and their corresponding extinction coefficients are reported in Table 2. 29 Phosphorescence spectra were taken for all the ketones at 77K in 2- methyltetrahydrofuran with ketone concentrations of about 0.04 M. The triplet energies of the ketones were calculated from the highest energy (0,0) band and are given in Table 3. E I? I' II L_Quan1um_¥19_lds - Quantum yields for product formation and for ketone disappearance were determined by irradiation at 313 nm or 366 nm in a merry- go-round apparatus at room temperature. Solutions containing 0.005-0.02 M ketone in benzene were irradiated in parallel with degassed benzene solutions of 0.1 M valerophenone as an actinometer.48 The ketone conversion was controlled at about 10%. All samples were degassed by three freeze-thaw cycles prior to irradiation. Compound to internal standard ratios were measured by GC or HPLC. Quantum yields are calculated by equation 1 and 2. o = [Cl/{lo x (1-1o-Ak)} (1) IO = [AP] / { 0.33 x (1 - 1o-Avp)} (2) where [C] is the concentration of the products, lo is the intensity of the light absorbed by the ketone solution. [AP] is the concentration of acetophenone from the valerophenone actinometer, Ak and Avp are the optical densities of ketone and valerophenone under the irradiation condition. When the A is larger 30 than 2, the term (1-10'A) can be ignored and the error is less than 0.01. Product quantum yields were obtained by adding 0.05 M thiophenol to the photolysis solutions. A plot of Quantum yields vs. the concentrations of HSPh are given in figure 1. The values of the quantum yields are listed in Tables 4-5. unpleLLiLQtime - Stern-Volmer quenching analysis was performed by 366 nm irradiation of the ketone solutions containing varying amounts of either naphthalene or 1-methylnaphthalene. Conversions were kept below 10% for the sample without quencher and the plots of (Dc/<1) vs concentrations of quenchers were linear up to quantum yield ratios of 3-5. (Dc/<1) = 1 + kq1;[Quencher] (3) According to equation 3, kq1: values are obtained from the values of slopes of the plots. They are listed in Tables 4-5. All the Stern-Volmer plots are presented in figures 2-12. 31 Table 1. Minimized Energies of Different Conformations of p-(Alkylthio)benzophenones in kcal/mole. ‘55.“ a p-t-BuSBP p-sec-BuSBP p-n-BuSBP p-BzSBP 0 38.94 35.79 33.81 40.42 15 38.31 35.45 33.50 40.07 30 36.76. 34.42 32.64 39.36 45 34.79 33.18 31.67 38.40 60 32.90 32.08 30.87 37.49 75 31.53 31.43 30.38 36.95 90 30.84 31.33 30.22 36.80 105 31.34 31.50 30.40 36.95 120 32.63 32.04 30.97 37.62 135 34.54 33.06 31.67 38.90 150 36.70 34.38 32.68 39.99 165 38.37 35.44 33.59 40.48 180 38.97 35.85 33.93 40.52 195 38.37 35.49 33.48 40.19 210 36.72 34.50 32.61 39.37 225 34.57 33.19 31.60 38.32 240 32.66 32.00 30.77 37.40 255 31.36 31.36 30.31 36.87 270 30.85 31.31 30.21 36.75 285 31.61 31.50 30.45 36.95 300 32.88 32.06 31.16 37.66 315 34.76 33.07 31.60 38.94 330 36.74 34.31 32.55 40.07 345 38.30 35.36 33.44 40.51 360 38.91 35.80 33.81 40.47 32 Table 2. UV Absorption Data for Various Ketones Ketones u,1c*1 n,1t‘2 n,1r* 313 nm 366 nm MMX (s) lmax (8) MMX (e) 8 6 p-BzSBP(Ha) 242(17732) 31 1 (20315) 17500 P-BzSBP(Bb) 315(18850) 334 p—BzSAP(H) 297(15871) 304(18340) 8900 p-BzSAP(B) 305(19557) 16200 1 5 p-t-BuSBP(H) 255(21680) 309(4580) 348(235) p-t-BuSBP(B) 312(4345) 4300 1 70 p-n-BuSBP(H) 244(14525) 315(18341) o-BzSBP(H) 243(20934) 279(5172) 334(855) o-BzSBP(B) 336(1077) 970 530 o-BzSAP(H) 230(16872) 270(5970) 334(2308) o-BzSAP(B) 338(1930) 1450 790 p—BrCH28P(Ha) 257124027) 348(59) 81 1 1o p—BrCH2BP(Bb) 344(181) 130 105 p-CICH28P(H) 253(23615) 348(142) 64 91 p-CICH28P(B) 344(158) 92 93 p-PhSOCH28P(H) 253(14470) 274(10925) p-PhSOCH2BP(B) 343(212) 1 1 1 p-PhSOzCH2BP(H) 255(19161) p-PhSO2CH28P(B) 344(169) 1 10 99 Valerophenone(H) 323(49) 45 4.8 Valerophenone(B) 321 (54) 51 3.8 p-PhSCH2AP(B) 510 1 2 p-PhSCH2BP(B) 1090 96 p—n-BuSCH2BP(B) 99 m-PhSCH2AP(B) 240 23 m-PhSCH28P(B) 490 84 p-t-BuSCH2BP(B) 342(234) 400 1 34 p-sec-BuSCH2BP(B) 344(234) 460 97 m-CICH2BP(B) 343(131 ) 77 70 p—BrCH2AP(B) 12 p-BrCHgAFKH) 250(3597) 289(286) ain cyclohexane. bin benzene. Table 3. Spectroscopic data for phenyl ketones. 33 Ketone 7.041(an IET1o_o)(kcal/mol)a M‘flnm) Aencm“) State BP 417.6(5) 68.5 (68.6)46 455.0 1469 ml: AP 391.2 (s) 73.1 (73.7)46 416.4 1539 n,1r* p-MeBP 415.2 (s) 68.9 (68.7)47 444.0 1574 n,1t‘ p—MeAP 397.2 72.0 (72.9)47 ---b -- m: m-MeBP 416 (s) 68.8 445 1574 n,1r* m-MeAP 393 72.8 (73.1)47 420 1644 m: p-BZSBP 446 64.1 -- - mt" p-t-BuSBP 421 (s) 67.9 452 1504 n.1r‘ p-sec-BUSBP 446 64. 1 —- -—- tut" p-n-BuSBP 440 65.0 -- -- 1r,n* p-BzSAP 438 65.3 — — 11.11' o-BzSBP 437 65.4 — -- mu" o-BzSAP 437 65.4 - -- 1m" p-PhSCHzBP 416 (s) 68.7 447.0 1644 n,1r* p—t-BuSCH2BP 419( s) 68.3 449.0 1609 n.1r’ p-n-BuSCHzBP 417 (s) 68.6 447.0 1609 ml: p—CICH2BP 417 (s) 68.6 447.0 1609 n.1r‘ p-PhSCH2AP 397.0 72.0 -- - mu" m-PhSCH2BP 416 (s) 68.8 447.0 1644 mt" m-PhSCHZAP 395 72.4 — -- 1w: aPhosphorescence Spectra at 770K in 2-Methyltetrahydrofuran in kcaI/mol. Triplet energy: ET = 2.86 x 104/ Mnm). bno vibrational structructure. 34 Table 4. Kinetic Data for Various Alkylthiophenylketones in Benzene. hv I E—SR' —> R'H + R'-R' + 1 ;__SH+ I 78 2 1. 2 3 4 Compound aka 1 a «>23 (1)33 (D43 kg‘tb p-BzSBP 0.40 0.15 0.17 125 p-t-BuSBP 0.37 0.18 683 p-sec-BuSBP 0.019 0.0052 7670 p-BZSAP 0.47 --- 0.16 --- 0.24 70 O-BZSBPc 0.0041 0.0041 --- 0.0026 --- 2.1 o-BzSAP 0.036 --- 0.018 --- 0.019 11.6 o-BzSAPC 0.081 0.081 --- 0.064 --- aIrradiation at 313 nm. bIrradiated at 366 nm. Naphthalene was used as quencher. C3in the presence of 0.05 M thiophenol. 35 Table 5. Kinetic Data for Various Para Substituted Methylbenzophenones in Benzene in the Presence of 0.05-0.1 M Thiophencl. Compound aka 4’2 (bphssph kg’tb p—PhSCH2BP 0.27 0.19C 0.18 0.74 p-t-BuSCH2BP 0.35 0.18c 27.6 p-2-BuSCH2BP 0.34 0.19c 16.9 p—BuSCH2BP 0.36 0.20C 16.5 p-BrCH2BP 0.45 0.300 <0.1 p-CICH2BP 0.48 0.48(3 11 p-PhSOCH2BP 0.33 0.35C <0.1 p-PhSOzCHzBP 0.35 0.29c 515 p-PhSCH2AP 0.31 0.35d 0.24 p-BrCH2AP 0.22 0256’ <0.1 m-PhSCHzBP 0.47 0.396 40 m-CICH2BP 0.036 0.0349 31 1 m-PhSCH2AP 0.36 0.321‘ 1.9 alrradiated in benzene at 313 nm. bIrradiated in benzene at 366 nm. Naphthalene was used as quencher. CQuantum yield of p-MeBP. dQuantum yield of p-MeAP. eQuantum yield of m-MeBP. fQuantum yield of m-MeAP. 36 0.4" a 0.3- - ‘5‘ (D 0 2 0., —o— p-PhSCHgAP —*— P'PhSCHzBP 0 0 I r I F I I f I I 0 00 0 02 0.04 0.05 0 08 0 10 0 12 [HSPh].M Figure 1. Quantum Yields of Irradiation of p-(Phenylthio)- methylbenzophenone and p-(Phenylthio)methylacetophenone vs. the Concentrations of Thiophencl. 37 3! 2d ' o (Do/d) 1 A 14 0 o-BzSAP A o-BzSBP 0 ‘ I W I ‘ I ' I V 1 0.0 0.1 0.2 0.3 0.5 [Quencher], M. Figure 2. Stern-Volmer Plot of o-(Benzylthio)acetophenone with 1-Methylnaphethalene and of o-(benzylthio)benzophenone with Naphthalene in Benzene Solution. (Do/d) Figure 3. 38 3'! A 2‘ A ‘ A . ' 1 O p-PhSCHzAP A p-PhSCHzBP 0 ' 1 ' I 1 I 0 1 2 3 [Naphthalene], M Stern-Volmer Plot of p-(Phenylthio)methylacetophenone and of p-(Phenylthio)methylbenzophenone with Naphthalene in Benzene Solution. O/ S 2 O..— I (D 'U :- 2 Q: We investigated several derivatives of acetophenone and benzophenone with sulfur-carbon bonds attached to the phenyl ring. To compare the results, several para and meta substituted halomethyl- benzophenones and halomethylacetophenones were also investigated. The results of photolysis of a variety of acetophenone and benzophenone derivatives are shown in Tables 4-8. All the compounds studied afford carbon-hetero atom homolytic bond cleavage products except for o- 50 (methylthio)benzophenone, p-(n-butylthio)benzophenone, and o-(octylthio)- acetophenone which are inert to the light. Wagner and Lindstrom”:51 reported the photolysis of p-(phenylthio)- methylacetophenone. The reaction afforded p-methylacetophenone as product. This reaction was suggested to occur via a homolytic carbon-sulfur bond cleavage process to generate radicals: o o 0 hv _, . Ph —> SPh HSPh _+ S CH2 CH3 In the present system, evidence for a reaction mechanism which involves free radicals as intermediates is given below. First, the formation of coupling products - disulfides and bibenzyls - can be well explained by the radical process which rules out heterolytic cleavage as a possible mechanism: as + C'HZR' FISCHzR' < g>~ RSSR + R'CHZCHZR' as + CHZR' Also the reactivity of sulfoxide is much higher than that of sulfone in spite of the fact that SOPh is a poorer anionic leaving group compared to SOzth52 51 Secondly, the trapping experiment of the reaction by thiophenol29:53 supported the radical process. In the absence of hydrogen donor, the reaction 0 SCHzPh h, o s- . o S. )b : 2b+CH2Ph —~/b+éH2Ph HSPh l 0 SH 0 s 2b + 0'13"“ )K : + PhCHZCHZPh 2 + SPh \ PhSSPh gives only radical coupling products. In presence of thiophenol, most of the radicals that escape the radical cage are trapped and hydrogen abstraction products are preferred. For example, the products of photolysis of o- (benzylthio)acetophenone are dibenzyl and 2,2’-dithiodiacetophenone, while 52 the products in the presence of HSPh are toluene, o-thioacetophenone and phenyldisulfide. The increase of the quantum yields indicates that the decrease of the coupling of the radicals back to ground state starting ketone. The change of the distribution of the products indicated that the radicals generated by homolytic S—C bond cleavage are intercepted by thiol before they can find each other. Based on the radical process, a mechanism of photoinduced homolytic sulfur-carbon bond cleavage of ketosulfides is presented in Scheme 2. All the detail of the mechanism will be discussed: k 3K‘ ' > [Radicals] RV km diffusion out 3C-T‘ of cage 1K* Radicals / \ HSPh hv 21:13:. K products products Scheme 2. Mechanism of 8-0 Bond Cleavage of Ketosulfides 53 838019818 It is well established that a radical cleavage processes involve initial formation of caged radical pairs which can diffuse apart or couple back to ground state starting compounds.43v54-55 The radicals that escape from the cage can then form coupling products or hydrogen abstraction products if there is a hydrogen donor in the reaction system. Wagner and Lindstrom studied the photolysis of some substituted phenacyl phenyl sulfides.43 The quantum yields of phenyl alkyl ketone formation increased to a maximum of about 0.4 in the presence of 0.05 M thiophenol. They concluded that about 40 % of the initial radicals escape from the radical cage before they couple to the starting ketones. The experimental data we obtained for the quantum yields vs. the concentration of thiophenol reach maximum value when the concentration increases to 0.02 M. The highest value for this maximum quantum yield is around 0.40. Similar results have also been reported for other triplet radical pairs.55 Therefore, we conclude that 40 % of the radicals escape from solvent cages. The photolysis of p-BzSBP or p-t-BuSBP in the presence of 0.1 M thiophenol gives only 4,4’- dithiodibenzophenone and p-thlobenzophenone since the p-benzoylphenylthiyl radical is more stable than phenylthiyl radical and thiophenol cannot trap all the radicals. The quantum yield of 4,4’-dithiodibenzophenone from irradiation of p- BzSBP and p-t—BuSBP is 0.17 and 0.18 (corresponding to 34% and 36% for the quantums yield for free radicals). Photolysis of p-BzSAP gave quantum yields of 4,4’-dithiodiacetophenone of 0.24(corresponding to 48% quantum yield for free radical). Therefore, we conclude that nearly all the thiyl radicals that escape the solvent cage are couple to disulfides for the para substituted (alkylthio)benzophenone or (alkylthio)acet0phenone and we can apply this result to the photolysis of p-sec-BuSBP. varil 093 max radic 60% conlir well-l kcallr k9l0n. and U direct] equal; Willie plot a, lhe Qt: 2500 i 54 Table 6 presents the maximum quantum yields for the photoproducts of a variety of keto sulfides together with some keto halides. Since the S-C bond cleavage is the only reaction that the photolysis of these sulfides undergo, the maximum of the quantum yields represent a measurement of the cage effect of S-C bond cleavage reaction. This indicates that 40% of the initially formed radicals are able to escape from the solvent cage to form products and the other 60% of the radicals couple back to starting ketones in the solvent cage. GI'III'II' III That the radicals are formed exclusively from triplet excited states is confirmed by quenching studies. Naphthalene and a-methylnaphthalene are well-known triplet quenchers with triplet excited state energy at 60.9 and 60.8 kcaI/mol,56 respectively, and can quench the triplet excited states of phenyl ketones (64-74 kcal/mol) with a diffusion controlled rate constant. Straight lines and unity intercepts obtained from the Stern-Volmer plot exclude any products directly from singlet excited states. The triplet lifetime of ketones can be obtained from the following equafion: r=SIope/kq where r is the triplet lifetime of ketone, slope is calculated from Stern—Volmer plot and kq is the rate constant of quenching reaction. It is widely accepted that the quenching of triplet ketones by energy transfer in the benzene solution at 25°C is diffusion-controlled and kq is about 6 x 109 M'1 s“.57 Scaiano and llag org; 3001 001 can SUIT] there where lorpl neces Ilpiet 0f [he Chemic mpkl; meaSu IISUls SUIIUf : 55 Wagner measured rate constants of several quenching reactions of various organic molecules with a number of triplet quenchers and found the value above was accurate.58 Table 7 gives the 1/1: value deduced from Stern-Volmer plot. The triplet lifetime is a measurement of how fast the excited triplet states can decay. The reciprocal of the triplet lifetime is generally expressed as the sum for rate constants of all the physical and chemical decay reactions which the excited state undergoes, i.e. 1/‘t=£kr+2kd where kr is the rate constant for a chemical reaction and kd is the rate constant for physical decay. For a reaction involving more than one process, it is necessary to estimate the individual contribution of each process to the overall triplet lifetime. Radiative deactivation (phosphorescence) usually has a rate constant kp of the order of 101- 104 54.59 It can not compete with other physical and chemical processes and therefore can be ignored in this system. The typical value for the rate constant kd of the radiationless decay of triplet phenyl ketones is in the order of 105 -106 S'1 .60 Wagner and Trumanf"1 measured ms for substituted acetophenones and benzophenones and the results fit this range very well. Therefore, it is reasonable to assume that the sulfur substituted benzophenones, acetoohenones, p-methylacetophenones 56 Table 6 Maximum Quantum Yields for photoproducts of Ketones ketones Product ‘Dmax p-BzSBP (p-BPS)2 0.17 p-t-BuSBP (p-BPS)2 0.18 p-sec-BuSBP (p-BPS)2 0.0052 p-BzSAP (p-APS)2 0.24 o-BzSBP o-HSBP 000“ o-BzSAP o-HSAP 0.081 p-PhSCH2BP p-MeBP 0.19 p-t-BuSCH2BP p-MeBP 0.18 p-sec-BuSCHzBP p-MeBP 0.19 p-n--BuSCH2BP p-MeBP 0.20 p-BrCH2BP p-MeBP 0.30 p-CICH2BP p-MeBP 0.48 p-PhSOCH2BP p-MeBP 0.35 p-PhSO2CH2BP p-MeBP 0.29 p-PhSCH2AP p-MeAP 0.35 p-BrCH2AP p-MeAP 0.25 m-PhSCH2BP m-MeBP 0.39 m-CICHzBP m-MeBP 0.034 m-PhSCH2AP m-MeAP 0.32 Table O 0 T1 (n "C _ C") p’PI p-l-B 9590- MB m-Ph m~Cl Table 7. Triplet lifetimes of Ketones 57 Compound kq’t, M‘1 1, sec 'I/‘t, S'1 p-BzSBP 125 2.1 x 10-8 4.8 x 107 p-t-BuSBP 683 1.1 x 10-7 8.8 x 106 p-sec-BuSBP 7668 1.3 x 10-6 7.8 x 105 p-BzSAP 69.9 1.2 x 10-8 8.6 x 107 o-BzSBP 1.97 3.2 x 10-10 2.9 x 109 o-BzSAP 11.6 1.9 x 10-9 5.5 x 108 p-PhSCHzBP 0.74 1.2 x 10--10 8.3 x 109 p-f-BuSCH2BP 27.6 4.6 x 10-9 2.2 x 108 p-sec-BuSCH2BP 16.9 2.8 x 10-9 3.6 x 108 p-n-BuSCH2BP 16.5 2.8 x 10-9 3.6 x 108 p-PhSOCH2BP <0.1 > 1.7 x 10-11 > 5.8 x 1010 p-PhSOzCHzBP 515 8.6 x 10-8 1.2 x 107 p-BrCH2BP <0.1 > 1.7 x 10-11 > 5.8 x 1010 p-CICH2BP 11 1.8 x 10-9 5.5 x 108 p-PhSCH2AP 0.24 4.0 x 10-11 2.5 x 1010 p-BrCH2AP <0.1 > 1.7 x 10-11 > 5.8 x 1010 m-PhSCH2BP 40 6.7 x 10-9 1.5 x 108 m-CICHzBP 311 5.2 x 10-8 1.9 x 107 m-PhSCHzAP 1.9 3.2 x 10-10 3.2 x 109 58 and p-methylbenzophenones have similar kd values. Since the triplet decay rates of most ketosulfides measured in this study are in the order of 107 -101 0 s", the kd accounts only less than 1% of the overall triplet decay of the compounds. Thus, the contribution of radiationless decay to the lifetimes can be ignored in most cases. As indicated in the lntroduction,23»29 the sulfur atom of sulfides quenches the triplet ketone intermolecularly or intramolecularly through charge- transfer(CT) interactions. Cohen and Guttenplan62 have measured intermolecular CT quenching of phosphorescence of benzophenone triplet by sulfides by charge-transfer in benzene. The kCT values for phenyl methyl sulfide and p-chlorophenyl methyl sulfide are 6.0 x 107 and 2.2 x 107 M-1 s-1 respectively. If we assume that the intermolecular CT process in our system is on the same order, and consider that the concentration of ketosulfides used in the experiment is usually about 2 x 10"2 M, the contribution of intermolecular charge-transfer ([K] x kCT) to triplet decay is calculated to be about 105-106 M'1 s". The low quantum yield of the photolysis of p-sec-BuSBP indicated an intermolecular charge-transfer process. Since the 1/1: of p-sec-BuSBP is only 7.8 x 105 M'1 5'1, the charge-transfer process is fast enough to compete and causes low quantum yield. Singer85 measured triplet self quenching in derivatives of benzophenone. A charge transfer process via exciplex intermediate was proposed. The rate constants of self quenching Iggq are 2.8 x 103, 2.2 x 107 and 1.8 x 106 M"1 s'1 for 4,4'-bis(dimethylamino)benzophenone, 4,4'- dimethoxybenzophenone and 4,4'-dimethylbenzophenone, respectively. He found that log ksq is linear in op+ (-1.7, -0.778 and -0.311 for dimethylamino, methoxy and methyl, respectively85). Since of of methylthio is 060485, the ksq value of alkylthiophenyl ketones is expected to be around 107 M'1 s4. inUa Unds phen; 59 Another physical decay process of triplet excited states of ketones is the intramolecular quenching by sulfur atom through a CT process. Wagner and Lindstrom29 measured several CT rate constant values (kcr = 5.5 x 109 s-1) of B-(n-butylthio)propiophenone in benzene. They also indicated that the phenylthio group is a less active quencher than the alkylthio group (for example kc-r = 2.9 x 109, 2.5 x 109, 0.8 x 109 s-1 for y-(n-butylthio)butyrophenone, y-(t- butylthio)butyrophenone and y—(phenylthio)butyrophenone respectively). The results we obtained for the photolysis of alkylthiophenyl ketones are unusual since the photolysis of p-BzSAP and p-BzSBP gave higher quantum yields(0.18 and 0.17, respectively) and low triplet reactivities(r = 1.2 x 10'8 s and 2.1 x 10'8 s, respectively) while their ortho analogs gave low quantum yields(0.064 for o- BzSAP and 0.0026 for o-BzSBP) and high triplet reactivities(1: = 1.9 x 10'9 s for o-BzSAP and 3.2 x 10--1 0 s for o-BzSBP). The unusual results are similar to the study reported by Padwa in the reactions of 8-keto sulfides.42 The different behavior of o-BzSAP and o-BzSBP being relative to p-BzSAP and p-BzSBP suggests a different mechanism for the ortho substituted ketones. The low quantum yields and short lifetimes suggest a rapid decay competing with radical cleavage, the formation of an intramolecular CT complex by the interaction of the excited carbonyl group and sulfur. The CT complex can undergo reverse charge-transfer process to generate a ground state starting ketone.42.43 Since the intramolecular charge-transfer process occurs through- space,63 in which five or six atom cyclic conformations are the most favorable, it is not feasible for the para substituted ketones to achieve a conformation that can form a CT complex: 60 i o' 5 8+ SCH2Ph kcr 0 SCHzPh k. ———> R 0 SCHzPh R R In the present system, the only products detected are the C-S bond cleavage products. Therefore, there is only one rate constant kr for the chemical process. The equation then can be written as 1/1:=kr+2‘,kd (4) where kr is the rate constant of the chemical process and EM is the sum total contribution of physical decay process. We already concluded that 40 % of the original radical pairs diffuse from solvent cages. By dividing the maximum quantum yields by 0.40, we obtained the quantum yields Or for the SC bond cleavage. Table 8 contains kr and de for alkylthiophenyl ketones. In the case of o- BzSBP and o-BzSAP, de equals the rate constant of intramolecular CT by sulfur atom(kCT) and the other decay processes can be ignored. The results are close to results reported by Wagner and Lindstrom.29 lntramolecular C-T in o- BzSAP is 7 times slower than in o-BzSBP. In the case of p-BzSBP, p-t-BuSBP and p-sec-BuSBP, de is the sum of contributions via intermolecular C-T by sulfide and nonradiative decay. Intermolecular C-T reaction and nonradiative decay cannot be detected within the experimental error for p-BzSAP. The result is reasonable, since 1/r is 8.6 x 107 s-1 and zkd is <106s-1. 61 Table 8 Kinetic Data for Alkylthiophenyl Ketones Compound (Dmax (Dr 1/1, s'1 kr, 6'1 de ,s'1 p-BzSBP 0.17 0.85 4.8 x 107 4.1 x 107 7.0 x 106 p-t-BuSBP 0.18 0.90 8.8 x 106 7.9 x 106 9.0 x 105 p-sec—BuSBP 0.0052 0.026 7.8 x 105 2.0 x 104 7.6 x 105 p-BzSAP 0.24 1.00 8.6 x 107 8.6 x 107 < 106 o-BzSBP 0.0041 0.0103 2.9 x 109 3.0 x 107 2.9 x 109 o-BzSAP 0.081 0.203 5.5 x 108 1.1 x 108 4.4 x 108 Table 9 contains values for kr and Xkd for alkylthio- ,chloro- and bromo- substituted methylphenyl ketones. The percentage that kr‘s contribute to the 1:“ values were obtained by dividing the maximum quantum yield by 0.40. The 2kd obtained represents total decay from the triplet excited state and is in a range of 103-1010 S'1 for most ketones. We already indicated that the rate constant of intramolecular C-T is in the range of 107-108 M'1 see1 for p-BzSBP, p-t- BuSBP and p-sec-BuSBP. If we use the same range for alkylthiomethylphenyl ketones, the contribution of C-T to 1/‘t lies in the range of 105-106 8’1, considering that sulfide concentration is only 0.01-0.02 M. Therefore, intermolecular C-T reaction can be ignored. Since no products other than the S- C bond cleavage products were detected, Ekd may represent some unknown processes that occurs from triplet excited states. 62 Table 9 Kinetic Data for Methylphenyl Ketones Derivatives. Compound 5.8 x 1010 > 4.4 x 1010 > 1.4 x 1010 p-CICH2BP 0.48 100% 5.5 x 108 5.5 x 108 < 107 p-PhSOCHzBP 0.35 88% > 5.8 x 1010 > 5.1 x 1010 > 7.0 x 109 p-PhSOzCHzBP 0.29 73% 1.2 x 107 8.7 x 106 3.3 x 106 p-PhSCH2AP 0.35 88% 2.5 x 1010 2.2 x 1010 3.0 x 109 p-BrCH2AP 0.25 63% > 5.8 x 1010 > 3.7 x 1010 > 2.1 x 1010 m-PhSCH2BP 0.39 98% 1.5 x 108 1.5 x 108 3.0 x 106 m-CICHzBP 0.034 8.5% 1.9 x 107 1.6 x 106 1.7 x 107 m-PhSCH2AP 0.32 80% 3.2 x 109 2.6 x 109 6.0 x 108 p-BrCH2VP50 0.25 63% > 5.8 x 1010 > 3.7 x 1010 > 2.1 x 1010 p-CICH2VP50 0.43 100% > 5.8 x 1010 > 5.8 x 1010 m-CICH2VP50 0.22 55% 2.9 x 108 1.6 x 108 1.3 x 108 apercentage of contribution to kr. 63 DB |"|' [El-SI II Several factors seem to affect the rates of the S-C bond cleavage reaction: the stability of the radicals, the SC bond energy and the nature of the triplet excited state. In free radical chemistry, some of the early work64 suggested the order of stability for sulfur radicals to be SPh > SOR > SR > SO2R. This was confirmed by Wagner and Lindstrom43.65 in their study of B-cleavage in phenacylsulfides. The relative rates they obtained are > 196 : 44 : 1 : 0.0078 for SPh, SOMe, S-t- Bu and SOzMe, respectively. The relative rates listed in Table 10 are determined by the feature of the leaving groups-- the well known relative stabilities66 of the radicals, 82 > t—Bu > sec-Bu > n-Bu. Table 10. Relative Rate for C-S Bond Cleavage of Alkylthiobenzophenone Compound kr (8'1 ) krel p-BzSBP 4.1 x 107 5.2 p-t-BuSBP 7.9 x 106 1 p—sec-BuSBP 2.0 x 104 0.0025 p-n-BuSBP < 103 < 0.0001 64 Table 11 Relative Rate for C-S and C-X Bond Cleavage of p-Methylbenzophenone Derivatives. Compound kr (8'1) krel p-PhSCH2BP 4.0 x 109 40 p-t-BuSCH2BP 1.0 x 108 1 p-sec-BuSCH2BP 1.7 x 108 1.7 p-n-BuSCH2BP 1.8 x 108 1.8 p-PhSOCH2BP > 5.3 x 109 > 510 p-PhSOzCHzBP 8.7 x 106 0.0087 p-BrCH2BP > 4.5 x 109 > 440 p-CICH2BP 5.5 x 108 5.5 The relative rates listed in Table 11 give as relative stabilities of sulfur and halogen radicals: PhSO ~ Br > PhS > CI > Alkyl-S > PhSO2. The order, SOPh > SPh > S-Alkyl > SOzPh, obtained in this study is what was expected and matches Lindstrom’sfi5 data very well. Since bromine is a much more stable radical than chlorine, it is no surprise that p-BrCH2BP reacts much faster than p-CICH2BP. Table 12 contains relative rates of C-SPh and C-X bond cleavage for meta and para substituted phenyl ketones. The cleavages of p-PhSCH2AP, p- BrCH2AP, p-BrCH2VP and p-CICH2VP are too fast to be quenched and the rate constants for bond cleavage are larger than 1010 S4. The extremely fast rate for bromides may also be caused by a heavy-atom effect. The ratio of rate 65 Table 12. Relative Rate for CS and C-X Bond Cleavage of Methylphenyl ketone Derivatives. Compound kr (8'1) krel p-PhSCH2AP 2.5 x 1010 p-BrCHzAP > 3.7 x 1010 p-BrCH2VP50 > 3.7 x 1010 --- p-CICH2VP50 > 5.8 x 1010 m-PhSCH2BP 1.5 x 108 94 m-CICH2BP 1.6 x 106 1 m-PhSCH2AP 2.6 x 109 16 m-CICH2VP50 1.6 x 108 1 p-PhSCH2BP 4.0 x 109 7.3 p-BrCH2BP > 3.7 x 1010 > 67 p-CICH2BP 5.5 x 108 1 constants for m-PhSCH2BP / m-CICH2BP and m-PhSCH2AP / m-CICH2VP are 94:1 and 16:1 respectively. The relative rates of p-PhSCHzBP and p—CICH2BP are in the same order (7.3 : 1 ). The relatively smaller rate constants for the meta substituted methylphenyl ketones show that a para-carbonyl stabilizes the benzyl radical by spin delocalization while a meta substituent cannot.87 66 That the ring substituents on benzophenone and alkyl phenyl ketones strongly affect the n,1r* and 1m" triplet excited states and excitation energies has been reported by several groups.67 Generally, a strong electron withdrawing group such as CF3 stabilizes the n,1c* excited state63 and an electron donating group stabilizes the 1m" state67d. Both benzophenone and acetophenone have n,1t* lowest excited states. Methylacetophenone and methoxyacetophenone have lowest 1c,1t* triplet excited states, but methylbenzophenone and methoxybenzophenone retain n,1r* lowest excited triplet states. This is because the energy gap between lowest n,1c* and 11,11" triplets is larger for benzophenone than for acetophenone and the electron donating groups -- methyl and methoxy -- are not strong enough to bring the energy of the triplet 1m" excited state lower than that of the n,lr* excited state.69 The thiomethoxy group can stabilize the tut“ triplet much more than a methoxy group.67d In our system, the molecules with a sulfur atom attached to the aromatic rings of both acetophenone and benzophenone have 1m" lowest triplet excited states, because the sulfur atom is a much better electron donor than an alkoxy group. The triplet energies of p-BzSBP, p-sec-BuSBP, p-n-BuSBP and o-BzSBP are in the range of 64.1 - 65.4 Koallmole and are about 3.0 - 4.4 kcal / mole lower than the energy of the n,1c* triplet excited state of benzophenone. The only exception is p-t-BuSBP, which has an n,1l:* lowest triplet excited state energy 0167.9 kcal / mole, only 0.6 kcal / mole below the n,1r* lowest triplet energy of benzophenone. Molecular mechanics calculations show that the most stable structure is structure 1 ( p. 68 ) with the SC bond plan perpendicular to the benzene ring. In this structure, the lone pair orbital of sulfur is only 30° out of plane with respect to the benzene ring and cannot provide enough overlap for the sulfur atom to donate electron density and stabilize the 11,16" triplet. 67 To achieve the best overlap, there are four possible conformations, 2, 3, 4 and 5 ( p. 68 ), with one of lone pair orbitals perpendicular to the benzene ring. The calculated energies for each conformations are different depending on what R is. With the large t-butyl, the energy needed to achieve conformation 2,3, 4 and 5 is about 5.9 kcal / mole and the energy barrier for the bond rotation is 8.10 kcal / mole. This keeps p-t-BuSBP in conformation 1. The corresponding energy parameters are: 3.1 kcal / mole and an energy barrier of 4.49 Kcal/ mole for p-sec-BuSBP, 2.4 and 3.79 kcal / mole for p-n-BuSBP, and 2.5 and 3.72 kcal / mole for p—BzSBP. Therefore, it is unlikely for p-t-BuSBP to donate as much electron density as the primary and secondary alkylthio compounds. On the other hand, the substituents on the methyl group of methylbenzophenone or methylacetophenone have little effect on the triplet excited states. Methylbenzophenone and all of its derivatives retain an n,1r* lowest triplet excited states while methylacetophenone and all of its derivatives have 1r,1r* lowest triplet excited states. 68 Table 13. Relative Energies for Conformations of Alkyl Thiobenzophenone.a 1 2 3 4 5 R AE1 AE2 AE3 AE4 AE5 n-Butyl 0 2.44 2.39 2.33 2.42 sec-Butyl 0 3.02 3.14 3.00 3.1 1 t-Butyl 0 5.86 5.98 5.90 5.92 Benzyl 0 3.11 2.57 3.35 2.56 akcal/mol It has been reported that coupling of the SC 0* orbital and benzoyl 11* orbital has a strong stabilizing effect on the triplet excited state and weakens the C—S bond 43 for phenacyl alkyl sulfides and phenacyl phenyl sulfides. Electron transfer to the C-S bond can cause rapid B-cleavage.7° A similar situation occurs in our system. With a CS bond attached to the benzene ring of the phenyl ketones, the CS 0* orbital can couple to the benzoyl 16* orbital to stabilize both n,1c* and 1m” triplet excited states. The mixing of the benzoyl 11* orbital with the C-S 0* orbital also weakens the C-8 bond and causes rapid bond cleavage. 69 Photochemically induced carbon-sulfur bond cleavage of both n,1r* and 1:,1r* triplet excited states has been reported.4’4’r4~"t»71 But there is a lack of examples to compare the reactivities of the two excited states. In the present system, both 11,1:* and n,1r* excited states undergo S-C bond cleavage. The kinetic results show that n,1r* triplet excited states undergo C-S bond cleavage faster than the corresponding n,1l:* triplet excited states: m-PhSCH2AP is about 17 times faster than m-PhSCH2BP, m-CICH2VP is 100 times faster than m- CICH2BP and p-CICH2VP is at least 10 times faster than p-CICH2BP. It is hard to compare p-PhSCH2AP with p-PhSCH28P since both reactions are too fast to be quenched. The reason for this is that Mr“ triplet excited states have about 4 kcal / mole higher energies than n,1r* triplet excited states and different spin distributions. To break the SC bond, bond dissociation energy must be less than the lowest triplet energy of ketosulfides. The sulfides we studied have the basic structures, ArS-CH2Ar, ArS-n—Alkyl, ArS-sec-Alkyl, ArS-t-Alkyl, n-AlkyIS-CH2Ar, sec-AlkylS-CH2Ar and t-AIkyIS-CH2Ar and BrCH2Ar and CICH2Ar. Several bond dissociation energies for some similar compounds have been reported72 by several groups. Table 14 lists some bond dissociation energies for some C-X bonds. The energy required for breaking a S-C bond to form radicals is 67.4 kcal / mole for C5H5$~CH3, about 10 kcal / mole lower than AlkylS-CH3. If the behavior of ArS-Alkyl is paralleled by AlkylS-Alkyl, the bond dissociation energy of ArS-Alkyl should be about 10 kcal / mole lower than AlkylS-Alkyl. Therefore, the bond dissociation energy for ArS-t-Bu would be about 56 Kcal / mole, ArS-- sec-Alkyl ~ 60 Kcal / mole, and for ArS-n-Alkyl ~ 65 kcal / mole which is little below the lowest triplet excited state. These data can explain why there is no reaction for the o-MeSBP, o-n-octyl-SAP, and p-n-BuSBP and why the reactivity of p-t-BuSBP is 400 times higher than that of p-sec-BuSBP. It is no surprise to 70 see the high reactivities of ArS-CH2Ph and Br-CH2Ar since their bond dissociation energies are much lower than that of ArS-Alkyl. One exception is the compound p-PhSO2CH2BP. Although the bond dissociation energy is very low (lower than that of p-PhSCH2BP), the rate constant for this compound is small. Table 14 Bond dissociation energies. RS-C Bond dissociation energy, kcal/mole PhS-CH3 67.4 02H58--t-Bu 66 C2H5S-CH2Ph 53 CH3802-CH2Ph 48 C2H58-Ph 77 AlkyIS-CH3 77 C2H58-n-Bu 75 C2H5S-i-Pr 70 Cl-CH2Ph 68 Br-CH2Ph 51 71 PART II PHOTOCYCLIZATION OF ORTHO-BENZOYL N-ALKYLANILINIUM IONS Results IE I' III II I' o-Benzoyl-N,N-dlbenzylaniline hydrochloride (Bz2NBP:HC|) was prepared by Sn2 reaction of o-aminobenzophenone and excess benzyl chloride followed by bubbling dry HCI gas into the benzene solution of o- benzoyl-N,N-dibenzylaniline. O O c": ”“2 PhCHzcl P; NICHZPMZ HCI (II: N*H(CH2Ph)2 O NaC03 O benzene O G CH3CN or o-Benzoyl-N-benzylaniline was prepared by Sn2 reaction of o- aminobenzophenone and one equivalent benzyl chloride. The attempt to separate its hydrochloride salt failed. By bubbling HCI through a benzene solution of o-(N-benzylamino)benzophenone, a liquid layer separarated at the bottom of the solution. NMR spectra of the liquid in CD30N showed that the NH 72 peak shifted down field which indicated a protonated o-(N- benzylamino)benzophenone. The effort to separate the protonated compound by removing solvent under reduced pressure failed and only o-(N- benzylamino)benzophenone was recovered. o 0 o ””2 PhCH2CI ”HICHZP“) ll N+H2(CH2Ph) or 050 seat». o-Benzoyltrimethylanilinium tetrafluoroborate (Me3NBPzBF4) and o- benzoyl-N,N-dimethylaniline hydrochloride and hydrotetrafluoroborate were prepared by methylation of o-aminobenzophenone with iodomethane followed by ion exchange. 0 NH 0 - g 2 Mel/NaOH ll N+ICH3>3' 11) NICHslz > C + C O O O K) K: o . o 0 II N (CHala ll +NHlCHeIz AgBF. lI *NHlCHsiz UGO Oct: ”Taft: 73 S,S-Dimethyl-o-Benzoylphenylsulfonium tetrafloroborate was prepared by methylation of o-(methylthio)benzophenone with iodomethane followed by ion exchange: 0 o + ('5 CH3 Mel / NaOH AgBF4 ('1, (CH3)2 or —-> *0 o-Benzoylanilinium chloride was prepared by bubbling HCI through a benzene solution of o-aminobenzophenone: 0 II ”“2 HC, "ml-13 ‘CG benzene, GOG C" 'Ieoooo 0“) .-::. 0 “3| n : . 0000 - (Mammy Irradiation of a degassed acetonitrile solution of M93NBP:BF4 at 313 nm afforded one product. After 100% conversion ( monitored by NMR ), the solvent was evaporated at room temperature under reduced pressure. The product was recrystallized from MeOH and identified as 1,1-dimethyl-3-hydroxy- 3-phenyldihydroindolium tetrafluoroborate by NMR, IR and mass spectrometry. 74 Irradiation of o-benzoyltrimethylanilinium tetrafluoroborate in the solid state for 24 hours also gave the same product in 100 % conversion: 0 fi(CH3)3 hv OH [\fiICHallae d 50008 4 ’IOH 00.. on 0--'-=1 0 u L"!=l 411: n 0,- 100: Irradiation of degassed an acetonitrile solution of o-benzoyI-N,N- dibenzylaniline hydrochloride at 313 nm produced two products. After 100 % conversion, the solvent was evaporated at room temperature under reduced pressure. N-benzyl,2,3-diphenylindole and an unknown product were separated by silica gel column chromatography. The product structure was confirmed by X-ray crystallography, NMR, IR and Mass spectra. The indole was totally converted to the unknown product after 24 hours irradiation at the same condition: + 0 NH(CH2Ph)2 hv’ CH3CN / N o o 1 II 75 WW3 Irradiations of degassed C03CN solutions of o-benzoyl-N,N-dimethylaniline hydrochloride or hydrotetrafluoroborate, o-dimethylthiobenzophenone tetrafluoroborate and o- aminobenzophenone hydrochloride for more than 48 hours gave no significant change as monitored by NMR. WWW Irradiation of a degassed solution of o-benzoyl-N-benzylaniline and trifluoromethanesulfonic acid in 003CN for more than 48 hours gave no significant reaction as monitored by NMR. Q IE' I' E || L_Quamum_fle.|ds; Quantum yields for photoproduct formation and starting ketone disappearance were measured. Ketone solutions 0.01-0.02 M in acetonitrile were irradiated at 366 nm or 313 nm in parallel with degassed benzene solutions of 0.1 M valerophenone as actinometer. All samples were degassed by three freeze-thaw cycles prior to irradiation. For o-benzoyl-N,N- dibenzylaniline hydrochloride, the percent conversion of ketone was controlled below 10%. Concentrations of ketone and product were measured by HPLC with reverse phase column. For o-benzoyltrimethylanilinium tetrafluoroborate, the quantum yield for starting ketone disappearance was measured both by UV spectroscopy at 340 nm or IR Spectroscopy at 1674516645 cm“. The following equations were used to calculate the quantum yields. The symbols in the equations 1 and 2 are the same as in part I. The quantum yields are listed in tables 16 and 17. The IR measurements are considered more accurate, since 76 we detected a minor byproduct which had strong UV absorption in the spectra region to be measured. ¢c=[cl/{on(1-1o-AC)} (1) lo = [AP] / {0.33*(1-1o-Avp)} (2) WW: Stern-Volmer quenching analysis was performed at 366 nm by irradiation of ketone solutions containing varying amounts of quenchers. Ethyl sorbate, sodium sorbate and 1-naphthylamine hydrochloride were used for quenching the photoreaction of o-benzoyl-N,N-dibenzylaniline hydrochloride in dry acetonitrile and aqueous acetonitrile. Conversions were controlled under 10% for the zero quencher sample and the highest value of (Do M) was about 5. Ethyl sorbate and 2,4-dimethyI-2,4-hexadiene were used for quenching the reaction of o-benzoyltrimethylanilinium tetrafluoroborate. The conversion of the starting ketone was 18 % for ethyl sorbate quencher, as measured by UV spectra and is 34 °/o for 2,4-dimethylhexadiene as measured by IR spectra. Since the UV absorbance of the photolysis solution increased slowly in dark after irradiation, indicating some thermal reaction is taking place, we consider the IR method for analysis to be more accurate. W The x-ray structure of 1-benzyl,2,3-diphenylindole is given in Figure 18 (p. 84 ). The sample was recrystallized from methanol. Detailed crystallographic parameters are given in the Appendix at the end of the thesis. 77 Table 15. Ultravioleta and Phosphoresenceb Spectra of the Derivatives of o- Benzoylaniline. Ketone Mp ET mt" n,rr* nm kcanoIe imam-z) mane) o-Me3NBPzBF4 401.2 71.3 256(17100) 333(95) o-BzzNBP 446.0 64.1 256(21 100) 353(1090) o-BzzNBPzHCI 452.0 63.3 249(18300) 359(730) BP 413.8 69.1 ain acetonitrile. bin MeOH/EtOH. Table 16. Quantum Yields and kqt: Values for Disappearance of o-BenzoyltrimethylaniIinium Tetrafluoroborate upon Irradiation in Acetonitrile solution. Method ¢-k kq‘t, M-1 UV 0.56 86 IR 0.34 146 The UV absorption spectra were recorded for the starting ketones in MeOH/EtOH(100:10). The wavelengths of the absorption maxima and their corresponding extinction coefficients are reported in table 15. 78 Phosphorescence spectra were taken for all the ketones at 77K in MeOH/EtQH(100:10) with ketone concentrations of about 10'4 M. The triplet energies of these ketones were calculated from the highest energy (0.0) band and are given in Table 15. Table 17. Quantum Yields and qu Values for N-benzyl,2,3-diphenylindo|e upon Irradiation of o-BenzoyI-N,N-dibenzylaniline Hydrochloride in Acetonitrile Solution. H20(°/o) in CH3CN 04, on we Mb 0 0.0145 0.0067 2.4 2 0.0112 0.0033 4 0.0046 0.0029 347 6 0.00099 0.0017 8 0.00099 0.00090 7.0 220 10 -— 0.00059 a Ethyl Sorbate as quencher. b Sodium Sorbate as quencher. 79 4- 0 3d (DO/(b 2- q 1 ' 0%H20 ° 8%H20 0 j I ' I ' I ‘ I ' I ' i 0.0 0.2 0.4 0.6 0.8 1.0 1.2 [Ethyl Sorbate], M Figure 13. Stern-Volmer Plot of o-Benzoyl-N,N-dibenzylaniline Hydrochloride by Quenching Formation of N-benzyl,2,3-diphenylindole with Ethyl Sorbate in 0 % and 8% Aqueous Acetonitrile Solution. 80 3H 0 O 2.: I “o 1 / 8%H20 ° 4%H20 0 ' l ' I ' I ' I V 1 v I 0.000 0.001 0.002 0.003 0.004 0.005 0.006 [Sodium Sorbate], M Figure 14. Stern-Volmer Plot o-Benzoyl-N,N-dibenzylaniline Hydrochloride by Quenching Formation of N-benzyl,2,3-diphenylindole with Sodium Sorbate in 4 % and 8% Aqueous Acetonitrile Solution. 81 0.02 '1 -A- BzZNBPzHCl —0— N-benzyl-2,3-diphenylindole (D 0.01- 0 . 00 ' I ' T ' I ' l r I 1 I % Water in Acetonitrile Figure 15. Effect of Water in Acetonitrile Solution on Quantum Yields of o-Benzoyl-N,N-dibenzylaniline Hydrochloride Disappearance and of N-Benzyl-2,3-diphenylindole formation. 82 (Do/(D 0 ‘ I fl I ‘ I f I 0.00 0.01 0.02 0.03 0.04 [Ethyl Sorbate], M Figure 16. Stern-Volmer Plot of o-Benzoyltrimethylanilinium Tetrafluroborate by Quenching Disappearance of o-Benzoyltrimethylanilinium Tetrafluroborate in Acetonitrile with Ethyl Sorbate Monitored by UV at 340 nm. 83 0 I 1 ' I 0.00 0.01 0.02 [2,4-chadicnc] , M Figure 17. Stern-Volmer Plot of o-benzoyltrimethylanilinium Tetrafluroborate by Quenching Disappearance of o-Benzoyltrimethylanilinium Tetrafluroboratewith 2,4-hexadiene in Acetonitrile Monitored by IR at 16745-16645 cm'1. 84 Figure 18. X-ray Structure of N-benzyl,2,3—diphenylindole 00‘ r 85 2.00 A H20 1 2 3 4 5 6 7 a 9 0.00 A I 280.0 nm 366.0 nm ‘ 450.0 nm Figure 19. W Spectra of 0.00203 M o-Benzoyl-N,N-dibenzylaniline 2.00 A 0.00 A Hydrochloride in Acetonitrile l 280.0 nm Figure 20 - 366.0 nm in Acetonitrile 450.0 nm UV Spectra of 0.0017 M o-Benzoyl-N,N-dibenzylaniline 86 DISCUSSION 95' l' IE Irradiation (hv> 313 nm) of o-benzoyltrimethylanilinium tetrafluoroborate in both solution and solid state yielded 1,1-dimethyl-3-hydroxy-3-phenyl-2,3- dihydroindolium tetrafluoroborate. The photochemistry of ketones with active 6- C-H bond has been studied systematically and the mechanism of the reaction is well established.13.19b»23s73 The reaction proceeds via S-hydrogen abstraction to generate a 1.5-biradical followed by cyclization to give products. The suggested photoreaction pathway of o-benzoyltrimethylanilinium tetrafluoroborate is shown in scheme 3. H O N+ CH 2 ( 3)'3BF hv * O N+(CH3)2 4 T (:1 BE, fiH?‘ or} N+(CH3)2 H N+ICHaI2 BF4 II BF4 Scheme 3. Hydrogen Abstraction Pathway for o-Benzoyltrimethylanilinium tetrafluoroborate. 87 Photolysis of o-benzoyI-N,N-dibenzylaniline hydrochloride afforded N- benzyI-2,3-diphenylindole. The cyclization products from o-benzoyI-N,N- dibenzylaniline hydrochloride suggested the same biradical process. The reaction pathways are summarized briefly in Scheme 4. Since the solution is acidic, the initial cyclization product N-benzon-2,3-diphenyI-2,3-dihydroindole hydrochloride eliminates a water molecule to give the final product. H O N+H(CH2Ph)2 , HP“ 0'. hv 0 N+HCH2Ph T CI" -fiHPh Ph H OH N+HCH2Ph H N+HCH2Ph -—-I-> ' - - c. > C of Ph N/‘Ph -H20 I Scheme 4. Hydrogen Abstraction Pathway for o-Benzoyl-N,N-dibenzylaniline Hydrochloride. 88 Bl'il' II'IIE 'I ISII Since the ammonium salts used for this study are not very soluble in benzene, we chose acetonitrile as solvent in which benzoyl anilinium salts dissolve easily. To determine the lifetime of triplet excited state by Stern-Volmer quenching experiment, it is extremely important to obtain accurate values of rate constants of quenching (kq). It is widely accepted that exothermic quenching process is a diffusion controlled reaction.74 Several work76'78 has been done to determine the kq value of energy transfer quenching in a number of solvents. Hammond75 used eq. 5 to estimate the lifetime of triplet excited state from kq’t values by assuming kq as given by equation 5: kdif = 8RT/om (5) where n is viscosity of the solvent and or is a constant obtained from the Debye equation. A widely accepted rate constant for triplet quenching in benzene at 25°C is 6 x 109 M'1 $4.57 Since acetonitrile is a less viscous solvent than benzene, it is expected that the kq value for energy transfer quenching in acetonitrile is larger than that in benzene. A kq value in acetonitrile of 1.0 x 1010 M45"1 is reported and widely accepted.76:77 Saltlel73 undertook a extensive study of energy transfer quenching of indeno[2,1-a1indene with azulene as a function of temperature in n-pentane, toluene, acetonitrile and t- butyl alcohol. He found that the kq values in acetonitrile fall in the same range. Therefore, triplet lifetimes in acetonitrile were calculated from the slopes of Stern-Volmer quenching plots (kq‘t) assuming that kq = 1.0 x 1010 M'1S'1 for hep 89 both o-benzoyltrimethylanilinium tetrafluroborate and o-benzoyl-N,N- dibenzylaniline hydrochloride. The results are listed in the Table 18. Table 18. Kinetic data for o-benzoyltrimethylanilinium tetrafluoroborate and o-benzoyl-N,N-dibenzylaniline Hydrochloride. Compound M93N+ > M60 and compounds 1 and 2 are expected to be major products. For benzyloxy and dibenzylamonium groups, the reactivities are comparable and a mixture of two isomers is expected: 98 PhHO Ph \ O hv ---N+ O— ——————> “-0 N+"’ / O \ 2 Ph Ph Ph 0 hv \ NH-l- 0—\ -——->PhCH20 NCH2Ph Ph’ r41 ph O or (PhCH2)2N Several of the following compounds are very useful to investigate. We indicated that the positive charge on the nitrogen will deactivate the adjacent C- H bond and compound 1 may indicate to what extent the positive charge may slow down the reaction. Compound 2 may give a cyclization product 5 which is a very common structure in the natural products. Compounds 3 and 4 may alSo give cyclization products since the positive charge on the nitrogen may reduce 99 the 1c,1r* characters of the triplet excited state and make the 8-hydrogen abstraction possible: 4. CH N 0 Ph ( 3) \CH2 Ph CH3 0H +N hv 100 EXPERIMENTAL E E I' !E '[i I' [III 'I 1.82113013 Benzene; One gallon of reagent grade benzene was repeatedly stirred with 200 ml portions of concentrated sulfuric acid for 24 hour periods until the sulfuric acid remained white. The benzene and the sulfuric acid were separated and the benzene was washed with distilled water and then saturated aqueous sodium bicarbonate solution. The benzene was separated, dried over sodium sulfate and filtered into a 5 l round bottom flask. Phosphorus pentoxide was added and the solvent was refluxed overnight.The benzene was distilled through an one meter column packed with stainless steel helices. The first and last 10% were discarded. Acetonitrile; One gallon of reagent grade acetonitrile was distilled from potassium permanganate. Sulfuric acid was added to the distillate and the distillate was decanted from the ammonium salts. It was then distilled through a column packed with glass helices. Only the middle 60% was collected. flames; Reagent grade hexanes was purified the same way as benzene. ZAmflnaLSIandaLds W15) (Aldrich) was purified by washing with sulfuric acid, then distilled by Dr. Peter J. Wagner. W) (Aldrich) was purified by recrystallization from ethanol. 101 W2), (Aldrich) was purified by washing with sulfuric acid, then distilled by Dr. Peter J. Wagner. WEED). (Aldrich) was purified by washing with sulfuric acid, then distilled by Dr. Peter J. Wagner. W), (Aldrich) was purified by recrystallization from ethanol. 121W), (Aldrich) was purified by recrystallization from ethanol. W2) (Aldrich) was purified by recrystallization from ethanol. W351) (Aldrich) in ether was washed with aqueous sodium bicarbonate solution and water, then dried over anhydrous sodium sulfate, finally distilled under reduced pressure. WM was prepared by the reaction of benzoyl chloride with n-decyl alcohol. n-decyl alcohol (50 g) was added to benzoyl chloride (50 g) in 220 ml ether in a 500 ml round bottom flask. The solution was refluxed overnight with stirring. Then it was cooled, washed with water, extracted with ether, dried over anhydrous sodium sulfate, finally concentrated in vacuo. Distillation under reduced pressure; B.p. 135° C / 0.7 mm; MS 262 (M+). WM was prepared by the same procedure as decyl benzoate. W (Aldrich) was purified by recrystallization from ethanol. Mummers W: (Eastman) was recrystallized from Ethanol. W: was distilled under reduced pressure. '_A was ren leer met mOII 102 W (aldrich) was used as received. WSorbic acid (Aldrich) was dissolved in ethanol. A solution of 1 equivalent NaOH in ethanol was added into the solution dropwise. The solvent was removed under reduced pressure. The residue was recrystallized from ethanol. mp > 250°C. WWW 1-Naphthylethylamine (Aldrich, 29) was dissolved in 40 ml EtOH in an 100 ml round bottom flask. HCI (37%, 1.159) in 10 ml H2O was added into the solution dropwise. The solvent was removed under reduced pressure. The residue was recrystallized from CH30N/H2O. A white crystal (0.699) was obtained. mp 255°C. 4.3910033 W458 A mixture of thiosalicylic acid (Aldrich, 99, 0.058 mole), NaOH (EM, 4.89, 0.12 mole), dimethyl sulfate (MCB, 11.49, 0.09 mole) and distilled H20 (36 ml ) in a 100 ml round bottom flask was refluxed for 6 hours. A solution of NaOH (EM, 99, 0.23 mole) in 25 ml distilled H20 was added to the reaction mixture. Separation of the solid formed with suction filtration afforded crude product (69, 60%) which was recrystallized from toluene: mp160-167°C. W450 A mixture of o-methylthiobenzoic acid (39, 0.018 mole), thionyl chloride (M08, 15 ml) and pyridine (Fisher, 4 drops) was refluxed in a 50 ml round bottom flask for 5 hours. The thionyl chloride was removed under reduced pressure. White needles (1.39, 40%) were recrystallized from ether, 74-78°C. W4“ A mixture of 0- methylthiolbenzoyl chloride (1.39, 0.0069 mole), benzene (EM, 9.2 ml, 0.10 mole) and 1.59 AICI3 (EM, 1.59, 0.011 mole) was stirred in a 25 ml round 103 bottom flask at room temperature for 16 hours. The reaction mixture was then washed with 10% NaOH solution followed by distilled water twice and then dried with CaCI2. Removing the solvent in vacuum yielded a yellow oil which was distilled in vacuum (140°C/0.07mmH9). NMR: (300 MHz, CDCI3) 5 2.41 (s, 3H), 7.21 (dt, J = 1.38 and J = 6.93 Hz, 1H), 7.35-7.50 (m, 5H), 7.56 (ft, J = 1.34 and J = 7.41 Hz, 1H), 7.77 (dd, J = 1.37 and J = 8.48 Hz,2H). 130 NMR (75 MHz,CDCI3):616.35, 124.36, 127.12, 128.40, 129.76, 130.08, 131.05, 133.03, 137.48, 137.75, 139.14, 196.89. IR: 1650 (C=O), 1590, 1580, 3030 cm-1. MS (EI) rn/e 228(M+), 213(100), 195, 134, 151, 105, 91, 77. W A mixture of 0- fluorobenzophenone (Aldrich, 6.59, 0.032 mole), K2003 (Baker, 59, 0.047 mole) and DMF (M08, 60 ml) in a 250 ml round bottom flask cooled in an ice bath was stirred with magnetic bar overnight. Benzyl mercaptan (Aldrich, 6.59, 0.052 mole) was then added dropwise into the solution. The reaction mixture was kept in an ice bath for 0.5 hour and then at room temperature for 12 hours. The reaction mixture was poured into cold water. The mixture was extracted with methylene dichloride (2 x100 ml). The organic layer was washed with saturated K2003/H20 solution (2 x100 ml). After removing the solvent under the reduced pressure, the residue was recrystallized from ethanol to afford white crystals (2.469, 25% yield): mp 68-69°C. IR (CCI4) v 3090, 3065, 3030, 2927,2857,1672 (C=O), 1598, 1449, 1284, 928 cm‘1 MS (EI) m/e 304 (M+). 213(100), 134, 91, 77 104 1H NMR (500 MHz, CDCI3): 5 4.03 (s, 2H), 7.1-7.2 (m, 5H), 7.25 (td, J = 1.40 and 7.03 Hz, 2H), 7.3-7.5 (m, 5H), 7.56 (tt, J = 1.41 and 7.23 Hz, 1H), 7.73 (qd, J = 1.80 and 7.02 Hz, 2H) 130 NMR (75 MHz,CDCI3): 5 39.61, 125.94, 127.12, 126.35, 128.92, 130.02, 130.38, 131.15, 133.06, 135.39, 136.81, 137.31, 140.68, 197.44 (two missing tertiary aromatic carbon peaks may have been overlaped with other tertiary carbon peaks) WW KOH (Baker. 1.79. 0.030 mole). toluene (Aldrich, 10 ml) and benzyl mercaptan (Aldrich, 3.79, 0.030 mole) were placed into a 250 ml round bottom flask, . The mixture was then stirred and heated to boil for 5 min. DMF (MCB, 50 ml) and p-chlorobenzophenone (Aldrich, 4.09, 0.018 mole) were added into the flask. The reaction mixture was refluxed for 27 hours. The reaction mixture was poured into cold water and extracted with methane dichloride ( 2 x 100 ml). The organic layer was washed with distilled water (2 x 100 ml). After removing the solvent under the vacuum, the residue was recrystallized from methanol to afford white crystals (2.59, 45%) : mp 80-84 °C. IR (CH2CI2): v 3084, 3063, 3026, 2926,1660 (C=O), 1589, 1448, 1317, 1280, 1089, 937,922 cm-1 1H NMR (300 MHz, CDCI3): 5 4.22 ( s, 2H ), 7.2-7.4 (m, 7H), 7.45 (1, J = 7.54 Hz, 2H), 7.56 (t, J = 6.98 Hz, 1H), 7.70 (d, J = 6.10 Hz, 1H), 7.74 (d, J = 7.26 Hz, 1H) MS (EI) m/e 304 (M+), 185, 91 (100), 77 13C NMR (75 MHz, CDCI3) 8 37.95, 127.45, 128.20, 128.96, 129.38, 129.45, 130.52, 131.30, 132.94, 135.08, 137.00, 138.39, 144.27, 196.43 105 W Sodium hydroxide (Baker, 59, 0.125 mole) and toluene (Aldrich, 40 ml) were placed in a 500 ml round bottom flask. Benzyl mercaptan ( Aldrich, 99, 0.073 mole) was added dropwise while stirring and DMF (MCB,100 ml) was then added. 2-Chloroactophenone (Aldrich, 109,0.065 mole) was added. The solution was refluxed for 12 hours. The reaction mixture was poured into cold distilled water (200 ml). The mixture was extracted with methylene dichloride (2 x 100 ml). The organic layer was washed with distilled water (2 x 100 ml). After removed the solvent under the vacuum, the residue was recrystallized with chloroform. White crystals ( 129, 76%) were obtained: mp141-144 °C. 1H NMR ( 300 MHz, CDCI3 )5 2.57 (s, 3H), 4.11 (s, 2H), 7.15-7.30 (m, 5H), 7.32-7.40 (m, 3H), 7.76 (dt, J = 7.54 and J =- 1.11 Hz, 1H) 13C NMR (75 MHz, CDCI3) 6 27.71, 37.08, 123.81, 126.40, 126.93, 128.22, 128.74, 130.36, 131.75, 135.22, 135.95, 140.41, 199.31 IR (CCI4) v 3089, 3068, 3031, 2925, 1678 (C=O), 1587, 1246, 1053 (:m'1 MS (EI) m/e 242 (M+). 151, 91 WW KOH (Baker. 2.39. 0.041 mole) and toluene (Aldrich, 10 ml) were placed in a 250 ml round bottom flask. The mixture was heated and stirred for 5 min. DMF (M08, 50 ml) and benzyl mercaptan (Aldrich, 49, 0.032 mole) were added. The solution was stirred for 5 min. p-Chloroactophenone (Aldrich, 59, 0.032 mole) was added dropwise. The reaction mixture was stirred and refluxed for 16 hours. The reaction mixture was poured into cold water. Extracted the mixture with methylene dichloride (2x100 ml). The organic layer was washed with water (2x100 ml). After removed the solvent under the vacuum, the residue was recrystallized with MeOH. A white crystal was obtained: mp 103-105 °C. 106 1H NMR (300 MHz, 00013) 5 4.22 (s , 2H), 2.55 (s, 3H), 7.2-7.4 (m, 7H), 7.63 (dt, J = 8.76 and J = 1.99 Hz, 2H) 130 NMR (75 MHz, CDCI3) 5 26.27, 36.94, 126.65, 127.37, 128.54, 128.59, 133.96, 136.08, 144.06, 196.94 (one missing aromatic tertiary carbon peak may overlapped with the peak at 128.59) MS (El) m/e 242(M+), 197, 119, 91(100) IR (CCI4) v (CH2CI2): 3069, 3066, 3031, 3010, 2925, 1666 (C=O), 1591, 1263, 1099, 954 cm-1 W KOH (Baker. 159. 0.27 mole) and toluene (Aldrich, 20 ml) were placed into a 50 ml round bottom flask. The mixture was then stirred and heated to boil for 5 min. A solution of p- chlorobenzophenone (Aldrich, 309, 0.13 mole) in DMF (M08, 20 ml) were added into the flask and a solution of n-Butyl mecaptan (Aldrich, 159, 0.17 mole) in DMF (M08, 10 ml) were added into the flask.. The reaction mixture was refluxed for 24 hours. The reaction mixture was poured into cold water and extracted with methylene dichloride ( 2 x 200 ml). The organic layer was washed with distilled water (2 x 200 ml). After removed the solvent under the vacuum, white crystals (9.59, 25% yield) were recrystallized from methanol: mp 80-84 °C. IR (CH2CI2): v 3084, 3063, 3026, 2926,1660 (C=O), 1589, 1448, 1317, 1280, 1089, 937,922 cm-1 1H NMR (300 MHz, CDCI3): 5 0.94 (1, J = 7.36 Hz, 3H), 1.47 (hextet, J = 726, 2H), 1.69 (It, J = 6.70, 2H), 2.99 (t, J = 7.50 Hz, 2H), 7.35 (d, J = 8.65 Hz, 2H), 7.46 (1, J = 6.96 Hz, 2H), 7.56 (1, J = 7.25 Hz, 1H), 7.7-7.6 (m, 4H) 136 NMR (75, CDCI3) 5 14.29, 22.69, 31.50, 32.41, 126.79, 128.90, 130.47, 131.29, 132.83, 134.54, 138.49, 145.03, 196.43 107 MS (FAB, NBA, Positive) m/e 270, 105 MS (EI) m/e 270 (100, M+), 227, 214, 193, 161, 137, 105. 77 W KOH (Baker. 20. 0.036 mole) and toluene (Aldrich, 10 ml) were placed into a 250 ml round bottom flask. The mixture was then stirred and heated to boil for 5 min. t-butyl mecaptan (Aldrich, 3.09, 0.033 mole) and DMF (MCB, 20ml) were added. A solution of p- chlorobenzophenone (Aldrich, 4.59, 0.021 mole) in DMF (M08, 30 ml) were added into the flask. The reaction mixture was refluxed for 36 hours. The reaction mixture was poured into cold water and extracted with methylene dichloride ( 2 x 200 ml). The organic layer was washed with saturated Na2C03/H20 (4 x 100 ml). After removing the solvent under the vacuum, the residue was recrystallized from ethanol to afford white crystals (3.19): mp 87-900 C. IR (CH2CI2): v 3078, 3062, 3026, 2965, 2936, 2894, 2862, 1665, 1591, 1550, 1302,1280, 937 cm-1 1H NMR (300 MHz, CDCI3): 81.34 (s, 9H), 7.50 (It, J = 1.04 Hz and J -- 7.20 Hz, 2H), 7.59 (td, J = 1.37 Hz and J = 7.42 Hz, 1H), 7.63 (td, J = 1.74 Hz and J = 6.46 Hz, 2H), 7.77-7.78 (m, 2H) 130 NMR (75, 00013) 5 30.37, 46.17, 127.97, 129.54, 129.63, 132.22 136.28, 136.99, 138.18, 196.12 (one missing aromatic quatenary carbon peak may overlapped with the peak at 136.28) MS (EI) m/e 270 (M+). 214 (100), 185, 152, 137, 105, 77 W KOH (Baker. 29. 0.036 mole) and toluene (Aldrich, 10 ml) were placed into a 250 ml round bottom flask. The mixture was then stirred and heated to boil for 5 min. 2-Butyl 108 mecaptan (Aldrich, 3.09, 0.033 mole) and DMF (MCB, 20ml) were added. A solution of p-chlorobenzophenone (Aldrich, 4.59, 0.021 mole) in DMF (M08, 30 ml) were added into the flask. The reaction mixture was refluxed for 36 hours. The reaction mixture was poured into cold water and extracted with methylene dichloride ( 2 x 200 ml). The organic layer was washed with saturated Na2003/H2O (4 x 100 ml). After removing the solvent under the vacuum, a yellow liquid (4.0 g) was obtained which was purified by silica gel column chromatography (Hexane). The purity was confirmed by HPLC. IR (CCI4): v 3078, 3062, 3031, 2969, 2925, 2873, 1661, 1590, 1318, 1273, 1089, 937, 922 cm-1 1H NMR (300 MHz, CDCI3): 5 1.02 (t, J = 7.30 Hz, 3H), 1.33 (d, J = 6.69 Hz, 3H), 1.56 (qdd, J = 7.14, J = 7.14 and J = 7.14 Hz, 1H), 1.72 (qdd, J = 7.50, J = 6.25 and J =- 7.49 Hz, 1H), 3.34 (qt, J = 7.36 and J = 7.38 Hz, 1H), 7.35 (dt, J = 6.31 and J =- 1.93 Hz, 2H), 7.44 (11, J = 7.05 and J = 1.22 Hz, 2H), 7.56 (tt, J = 7.60 and J - 1.36, 1H), 7.6-7.8 (m, J = 6.30, 1.66, 1.47 and 6.17 Hz, 4H) 130 NMR (75 MHz, 00013) 5 11.14, 20.13, 29.20, 43.16, 128.41, 126.46, 130.00, 130.72, 132.40, 134.60, 137.92, 143.48, 196.22 MS (EI) m/e 270 (M+). 241, 214(100), 137, 105, 77 WM A mixture of o-tluoro- acetophenone (Aldrich, 4.19, 0.026 mole), K2003 (Baker, 3.89, 0.028 mole) and DMF (M08, 40 ml) in a 250 ml round bottom flask cooled in an ice bath was stirred with magnetic bar. n-octyl mercaptan (Aldrich, 3.59, 0.023 mole) was then added dropwise into the solution. The reaction mixture was stirred at room temperature for 24 hours . The reaction mixture was poured into cold water. The mixture was extracted with methylene dichloride (2 x100 ml). The organic layer was washed with saturated K2C03/H20 solution (2 x100 ml). The organic layer 109 was dried with M9804. After removing the solvent under the vacuum, the residue was recrystallized from ethanol to afford white crystals (3.59, 47% yield). mp 40-41°C. IR (CCI4) v 3060, 2960, 2930, 2660, 1660 (C=O), 1590, 1465, 1435, 1247, 1055, 955 cm" MS (EI) m/e 264 (M+). 249, 151 (100), 137, 109, 91,77 1H NMR (300 MHz, CDCI3) 5 0.66 (1, J = 6.98 Hz, 3H), 1.06-1.16 (m, 6H), 1.44 (quintet, J = 7.26 Hz, 2H), 1.69 (11, J = 7.54 and J = 7.30 Hz, 2H), 2.67 (t, J =- 7.50 Hz, 2H), 7.16 (dt, J = 1.39 and J = 6.98 Hz, 1H), 7.35 (dt, J = 1.40 and J = 8.10 Hz, 1H), 7.41 (dt, J = 1.40 and J = 6.36 Hz, 1H), 7.75 (dd, J = 1.39 and J = 6.61 Hz, 1H) 13C NMR (75 MHz, CDCI3) d 13.74, 22.31, 27.89, 28.27, 28.85, 28.90, 31.51, 32.14, 123.72, 126.29, 130.79, 132.01, 135.64, 141.24, 199.76 (one missing CH2 peak may overlaped with another CH2 peak) WW 4-Methylacetophenone (Aldrich, 559, 0.41 mole), N-bromosuccinimide (MC/B, 609, 0.34 mole), benzoyl peroxide (OR, 0.59, 0.0021 mole) and 200 ml CCI4 (Mallinckrodt) were placed in a 500 ml Three neck round bottom flask. The reaction mixture was stirred with magnetic stirring bar and heated to reflux for 4 hours. The hot mixture was filtered with suction filtration. The solid was washed with hot CCI4 (2x50 ml). The solvent was removed from filtrate under reduced pressure. A yellow liquid (104-110°C/0.5mmH9) was obtained which turned out to be a white solid after cooled in refrigerator. White crystals were recrystallized from ethanol. mp 44-47 °C 1H NMR (300 MHz, CDCI3) 5 2.56 (s, 3H), 4.46 (s, 2H),7.46 (d, J = 6.40 Hz, 2H), 7.90 (d, J = 8.40 Hz, 2H) 110 130 NMR (75 MHz, 00013) 5 25.93, 31.47, 126.43, 126.66, 136.46, 142.47, 197.26 IR (CHCI3) v 3036, 3007, 2973, 1691 (C=O), 1608, 1574, 1412, 1356, 1226, 1074, 1016, 956 cm-1 MS (FAB, NBA, Positive) m/e 215, 213 (M + 1). MS (El) m/e 212 (M+). 197, 133, 116 (100), 105,90 WWW Iii-Bromomethyl- acetophenone (119, 0.052 mole) was dissolved in ethanol (50 ml) in a 250 ml round bottom flask. Thiophencl (Aldrich, 5.79, 0.052 mole) was added in to a flask containing a solution of KOH (Baker, 2.99, 0.052 mole) in 95% ethanol (50 ml). The latter solution was added to the former one. After 10 minutes' stirring, distilled water (300 ml) was added into the reaction mixture. A white solid was precipitated and the reaction mixture was cooled in an ice bath to 0°C. The reaction mixture was filtered by suction filtration. White crystals (8.59, 68% yield)were recrystallized from ethanol. mp 90-92 °C 130 NMR (75 MHz, 00013) 5 26.55, 39.05, 126.62, 126.55, 126.92, 128.95, 130.47, 135.39, 136.05, 143.27, 197.60 1H NMR (300 MHz, CDCI3) 5 2.58 (s, 3H), 4.13 (s, 2H), 7.2-7.3 (m, 5H), 7.34 (d, J = 11.70 Hz, 2H), 7.66 (d, J = 6.10, 2H) IR (CCI4) v 3060 , 2960, 2920, 1685 (C=O), 1605, 1255, 960 cm'1 MS (EI) m/e 242 (M+). 199, 133 (100), 105, 90 WE) p-Methyibenzophenorte (Aldrich,129, 0.061 mole), N-bromosuccinimide (MC/B,119, 0.062 mole), benzoic peroxide (OR, 0.19, 0.0004 mole) and CCI4 (Mallinckrodt, 40 ml) were added into a 250 ml round bottom flask. The reaction mixture was stirred and 111 refluxed for 3 hours. The reaction mixture was filtered by suction filtration. The solvent was removed from filtrate under reduced pressure. A white solid (13 9, 78% yield) was obtained after beingrecrystallized from ethanol. mp 100- 105 °C. 1H NMR (300 MHz, 00013) 5 4.53 (s, 2H), 7.45-7.55 (m,4H), 7.60 (11, J = 7.45 and J = 1.34 Hz, 1H), 7.79 (m, 4H) 130 NMR (75 MHz, 00013) 5 31.60, 127.99, 126.60, 129.65, 130.19, 132.24, 137.01, 137.08, 141.80, 195.85 MS (EI) m/e 274 (M+). 195 (100), 167,105.77 IR v 3080, 3060, 3030, 1730,1630 (C=O), 1615, 1600,1275, 980, 950 cm'1 W m-Methylbenzophenone (Aldrich,129, 0.061 mole), N-bromosuccinimide (MC/8,119, 0.062 mole), benzoic peroxide (OR, 0.19, 0.0004 mole) and CCI4 (Mallinckrodt, 50 ml) were added into a 250 ml round bottom flask. The reaction mixture was stirred and refluxed for 2 hours until red color disappeared. The reaction mixture was allowed to cool to room temperature and the reaction mixture was filtered by suction filtration. The solvent was removed from filtrate under reduced pressure. A liquid (10 9) was obtained by distillation (160-170 °C/1.0mm). A white solid was recrystallized from ethanol. mp 60-62 00 1H NMR (300 MHz, 00013) 5 4.53 (s, 2H), 7.50 (1, J = 6.03 Hz, 3H), 7.61 (1, J = 6.43 Hz, 2H), 7.71 (d, J = 7.65 Hz, 1H), 7.78-7.84(m, 3H) 130 NMR (75 MHz, 00013) 5 31.82, 126.02, 126.46, 129.66, 130.03, 132.30, 132.59, 136.90, 137.78, 137.84, 195.98 (one missing aromatic quatenary carbon peak may overlapped with another aromatic quatenary carbon peak ) MS (EI) m/e 276, 274, 195, 165, 152, 105, 90, 77 112 IR (CCI4) v 3070, 3064, 3032, 2974, 2927, 2885, 1669, 1599, 1449, 1340, 1224 cm'1 W m-Methylbenzo- phenone (Aldrich, 59, 0.026 mole), N-bromosuccinimide (MC/8,59, 0.028 mole), benzoic peroxide (OR, 19, 0.004 mole) and CCl4 (Mallinckrodt, 30 ml) were added into a 100 ml round bottom flask. The reaction mixture was stirred and refluxed for 1.5 hours until yellow color disappeared. The solvent was removed under reduced pressure. The residue was transferred to a 100 ml round bottom flask and 40 ml DMF was then added. A solution of 1.4 9 KOH and 2.7 9 thiophenol in 20 ml 95% EtOH was added dropwise. It was kept stirring at room temperature for 3 hours. The reaction mixture was poured into 100 ml H20 and extracted with methylene dichloride. Solvent was removed under reduced pressure to give yellow oil (39). A colorless liquid product was purified by silica gel column chromatography (50:50, hexane/CCI2H2). 1H NMR (300 MHz, 00013) 5 4.15 (s, 2H), 7.20-7.35 (m, 4H), 7.40-7.60 (m, 6H), 7.67-7.75 (m, 4H) 130 NMR (75 MHz, 00013) 5 36.71, 126.89, 126.44, 126.69, 129.05, 129.08, 130.16, 130.52, 130.60, 132.61, 133.00, 135.65, 137.63, 137.90, 136.15, 196.76 MS (E1) m/e 304, 210, 195, 105,77 (100) IR (CCI4)v 3056, 3032, 2958, 2927, 1664, 1599, 1563, 1481, 1433, 1317, 1309, 1262, 1234 cm-1 W 3-Methyiactophenone (Aldrich, 8.29, 0.061 mole), N-bromosuccinimide (MC/B, 119, 0.062 mole), benzoic peroxide (OR, 0.19, 0.0004 mole) and 50 ml CCI4 (Mallinckrodt) were 113 placed in a 250 ml round bottom flask. The reaction mixture was stirred with magnetic stirring bar and heated to reflux for 25 min until red color disappeared. The solvent was removed under reduced pressure. Distillation afforded a liquid (5.3 g, 90-100°C/0,2mm). 1H NMR (300 MHz, CDCI3) 8 2.58 (s, 3H), 4.50 (s, 2H),7.42 (t, J = 7.54 Hz, 1H), 7.56 (dm, J = 7.62 Hz, 1H), 7.85(d, J = 7.54 Hz, 1H), 794(1), 1H) 13C NMR (75 MHz, CDCI3) 8 25.92, 31.86, 127.93, 128.31, 128.80, 133.24, 137.24, 138.07, 197.34 IR (CCI4) v 3067, 3030, 3004, 2962, 2925, 2862, 1693, 1603, 1587, 1550, 1441,1356,1277,1217,1192 cm-i MS (El) m/e 214, 212(M+), 199, 197, 171, 133(100), 118, 90 WW p-Bromomethyl- benzophenone (79, 0.025 mole) was dissolved in DMF (MCB, 40 ml) in a 250 ml round bottom flask. Thiophencl (Aldrich, 2.79, 0.025 mole), KOH (Baker, 1.49, 0.025 mole) and 95% EtOH (40 ml) were added into another 250 ml round flask and stirred for 10 minutes. The latter solution was then added into the former one. The reaction mixture was stirred for 30 minutes. Distilled water (300 ml) was added in the reaction mixture and a white solid was precipitated. The reaction mixture was allowed to cool in an ice bath. The solution was filtered by suction filtration. White crystals (6.5g, 85% yield) were recrystallized from ethanol. mp 49 - 51 ° 0. MS (El) m/e 304 (M+). 195 (100), 167, 105,77 IR (CCI4) v 3079, 3058, 3032, 2935, 1664, 1606, 1581, 1277, 937 cm'I; 1HNMR (300 MHz, 00013) 5 4.14 (s, 2H), 7.15-7.30 (m, 5H), 7.36 (d, J = 6.51 Hz, 2H), 7.46 (1, J = 7.69 Hz, 2H), 7.57 (1, J = 7.29 Hz, 1H), 7.71 (d, J = 6.66 Hz, 2H), 7.76 (d, J = 6.93, 2H) 114 130 NMR (75 MHz, 00013) 5 36.69, 126.96, 128.44, 126.66, 129.01, 129.14, 130.16.130.55, 132.56. 135.70, 136.58, 137.85, 142.79, 196.75 WWW p-(Phenylthiol- methylbenzophenone (0.78 9, 0.0026 mole) was dissolved in acetone (Baker,10 ml) in a 50 ml round bottom flask. 30% Aqueous hydrogen peroxide (Baker, 1 ml, 0.0098 mole) was then added to the solution. The reaction mixture was stirred for 48 hours at room temperature until white solid formed. The reaction mixture was filtered by suction filtration. A white solid (0.609, 72% yield) was obtained. mp152-154 °C. 1H NMR (300 MHz, 00013) 5 4.05 and 4.12 (AB q, J = 12.63 Hz, 2H), 7.07 (dt, J = 6.09 and J = 1.92 Hz, 2H), 7.24-7.49 (m, 7H), 7.56 (11, J =- 7.57 and J = 1.40 Hz, 1H), 7.66 (11, 6.30 and J -_- 1.77 Hz, 2H), 7.74 (td, J = 7.02 and J = 1.44 Hz, 2H) 130 NMR (75 MHz, 00013) 5 62.91, 124.46, 126.49, 129.19, 130.174, 130.21, 130.45, 131.57, 132,75, 133.87, 137.43, 137.59, 142.67, 196.56. IR (CHCI3) 3456, 3069, 3007, 1658 (C=O), 1606, 1446, 1278, 1043 (8:0), 929, 702. MS (FAB, NBA, Positive) m/e 321(M+1). MS (El) m/e 320 (M+). 304, 195 (100), 167, 105, 90, 77. WWE p-(Phenyl- thio)methylbenzophenone (29, 0.0066 mole) and glacial acetic acid (Mallinckrodt, 25 ml) were placed in a 50 ml round bottom flask. 30% Aqueous hydrogen peroxide (Baker, 39, 0.026 mole) was then added. The reaction mixture was stirred at room temperature for 17 hours. It was extracted with CHC|3 (3 x 20 ml) followed by H20 (2 x 20 ml) and saturated NaH003 solution (2 x 20 ml). The organic layer was separated and the solvent was removed 115 under reduced pressure. The solid obtained was recrystallized with ethanol. White crystals (1.59, 68% yield) was recrystallized from ethanol. mp 155-156 °C. MS (EI) m/e 336 (M+),195,167,141,105,77. 1H NMR (300 MHZ, CDCI3) 8 4.39 (s, 2H), 7.23 (d, J = 8.10 Hz, 2H), 7.49 (td, J = 7.53 and J = 1.39, 4H), 7.60 (11, J = 7.26 and J = 2.51, 2H), 7.70 (dm, J = 8.10, 4H), 7.76 (dd, J = 6.98 and J = 1.67, 2H). 130 NMR (75 MHz, 00013) 195.94, 147.66, 137.67, 137.77, 137.23, 133.93, 132.63, 132.41, 130.63, 62.64. IR v 3552, 3069, 3026, 1660 (C=O), 1590, 1448, 1302 (S=O), 1278, 1155 (Sr-O) WEE p-Methylbezophenone (Aldrich, 69, 0.030 mole), sulfuryl chloride (MCB, 49, 0.030 mole) and 0014 (Mallinckrodt, 20ml) were placed into a 50 ml round bottom flask. After stirred for 2 minutes, benzoyl peroxide (OR, 100 m9, 0.0004 mole) was added into the reaction mixture. The reaction mixture was refluxed for 24 hours with stirring. The reaction mixture was filtered by suction filtration and the solvent was removed under reduced pressure. White crystals (4.09, 58% yield) were recrystallized from ethanol. mp 94-97 °C. 1HNMR (300 MHz, 00013) 5 4.64 (s,2H),7.50 (dd, J = 8.51 and J = 1.89, 4H), 7.60 (tt, J = 7.41 and J = 1.38, 1H), 7.80 (dd, J = 8.02 and J = 1.87, 4H) 130 NMR (75 MHz, 00013) 5 44.47, 127.99, 126.06, 129.65, 130.12, 132.24, 137.02, 137.13, 141.39,195.94 IR (CCI4) v 3310, 3084, 3062, 3031, 2957, 2925, 2868, 2857, 1667, 1608, 1549, 1446, 1317, 1277, 1176, 939 MS (FAB, NBA, Positive) m/e 231 (M + 1) MS (EI) m/e 230 (100, M+), 195, 181, 167, 153, 125, 105, 90, 77 116 W381 m-Methyibezophenene (Aldrich, 69, 0.030 mole), sulfuryl chloride (MCB, 49, 0.030 mole) and COM (Mallinckrodt, 20ml) were placed into a 100 ml round bottom flask. After stirring for 2 minutes, benzoyl peroxide (OR, 100 m9, 0.0004 mole) was added into the reaction mixture. The reaction mixture was refluxed for 3 hours with stirring. The solvent was removed under reduced pressure. Distillation afforded a liquid (163 oC/1.0 mm, 5.0 9). White crystals were recrystallized from ethanol. mp 43-46 °C. 1HNMR (300 MHz)5 4.65 (s,2H),7.47-7.54 (m, 3H), 7.59-7.67 (m, 2H), 7.76 (11, J = 7.69 and J = 1.53, 1H), 7.79-7.86(m, 3H) 130 NMR (75 MHz, 00013) 5 44.88, 128.01, 128.38, 129.59, 129.68, 132.10, 132.27, 136.95, 137.51.137.76, 196.02 (one missing aromatic tertiary carbon peak may overlapped with the peak at 129.68 ppm) IR (CCI4) v 3068, 3031, 2957, 2925, 2867, 1666, 1599, 1587, 1549, 1148, 1319, 1286, 1261, 1211, 964 om-i MS (E1) m/e 230 (M+) 195, 181, 165, 153, 125, 105(100), 77 WW 4-Bromomethyl- benzophenone (69, 0.022 mole) , n-butylmercaptan (29, 0.022 mole) and KOH (1.29, 0.021 mole) were placed into a 250 ml round bottom flask. 95% Ethanol (100 ml) was then added. The reaction mixture was refluxed for 12 hours with stirring. The reaction mixture was poured into a saturated Na2003/ H2O solution (100 ml) and extracted with CHCI3 (2 x 100 ml). Organic layer was washed with saturated Na2003 / H2O solution (2 x 100 ml). The organic layer was separated and solvent was removed under reduced pressure. A liquid was obtained by distillation (164-165°C / 0.2 mm). 117 1H NMR (300 MHz, 00013) 5 0.87(t, J = 7.26 Hz, 3H), 1.36(hextet, J = 6.96Hz, 2H), 1.54(11, J = 6.98 Hz, J = 8.09 Hz, 2H), 242(1, J = 6.32 Hz, 2H), 3.74(s,2H), 7.44(tq, J = 1.66 and 6.37 Hz, 4H), 7.56(tt, J = 1.39 and 7.54 Hz, 1H), 7.76(tt, J = 1.67 and 6.26 Hz, 4H) 130 NMR (75 MHz, 00013)514.32, 22.61, 31.89, 31.91, 36.75, 128.91, 129.36, 130.61, 131.03, 132.99, 136.64, 136.349, 144.41, 197.44. IR (0014) v 3310, 3080, 3060, 3030, 2961, 2932, 2650, 1664, 1606, 1317, 1277, 937 om-i MS (FAB, NBA, Positive) m/e 265 (M+1), 195, 105, 77 MS (EI) m/e 264, 226, 209, 185 (100), 178, 167, 152, 133, 122, 105, 90, 77 WW m-Bromomethyl- acetophenone (4.89, 0.023 mole) and 95% ethanol (25 ml) were placed into a 250 ml round bottom flask. A solution of thiophenol (aldrich,3.0 9, 0.027 mole) and KOH (0.8 g, 0.014) in 95% Ethanol (25 ml) was then added dropwise. The reaction mixture was refluxed for 1 hour with stirring. The reaction mixture was poured into H20 (100 ml). The solution was then extracted with CH013 (200 ml). The organic layer was washed with saturated Na2003 / H2O solution (4 x 50 ml). The organic layer was separated and dried over MgSO4. The solvent was removed under reduced pressure. A liquid (4 9) was obtained by distillation (159 °C/0.2 mm). It was purified with silica gel column chromatography (Hexane/AcOEt). 1H NMR (300 MHz, 00013) 5 2.55(s, 3H), 4.15(s, 2H), 7.2-7.3(m, 5H), 7.38(tt, J .-. 7.23 and J = 1.13 Hz, 1H), 7.77(m, 1H), 7.61-7.64(m, 2H) 130 NMR (75 MHz, 00013) 5 25.88, 36.31, 126.42, 126.75 126.31, 128.39, 128.56, 130.15, 135.13, 136.92, 137.93, 133.08, 197.78 118 IR (0014) v 3078, 3067, 3009, 2957, 2925, 2657, 1691, 1585, 1550, 1461, 1439, 1358, 1275, 1230, 1188, 1026 cm-1 MS (EI) m/e 242 (M+), 218, 133, 109. 91,77 WWW 4-Bromomethyl- benzophenone (4.59, 0.016 mole), 95% ethanol (25 ml) and acetonitrile (25 ml) were placed into a 250 ml round bottom flask. A solution of t-butylmercaptan (aldrich,1.5 g, 0.017 mole) and KOH (1.09, 0.018 mole) in 95% Ethanol (25 ml) was then added dropwise. The reaction mixture was refluxed for 5 hours with stirring. The reaction mixture was poured into H20 (100 ml). The solution was then extracted with CHCI3 (200 ml). The organic layer was washed by saturated Na2003/ H20 solution (3 x 100 ml) and NaH003 / H2O solution (100 ml). The organic layer was separated and dried over MgSO4. Removed the solvent under reduced pressure. White crystals (4 g) were recrystallized from ethanol. mp 75-7700. 1H NMR (300 MHz, 00013) 5 1.37(s, 9H), 3.63(s, 2H), 7.48(tq, J = 6.72 and J .—. 1.73 Hz, 4H), 7.59(11, J = 7.24 and J = 1.41 Hz, 1H), 7.77(tq, J = 6.24 and J = 1.28 Hz, 4H) 130 NMR (75 MHz, CDCI3) 8 30.72, 33.09, 43.07, 128.40, 129.04, 130.14, 130.55, 132.48, 136.27, 137.92, 144.02, 196.70 IR (CCI4) v 3078, 3062, 3030, 2963, 2941, 2925, 2899, 2862, 1665, 1606, 1549, 1317, 1306, 1277, 1176, 937 cm-1 MS (El) m/e 264 (M+), 226 (100), 195, 167, 150, 105, 90, 77 W53 P-Bromo- methylbenzophenone (4.59, 0.016 mole), ethanol (25 ml) and acetonitrile (25 ml) were placed into a 250 ml round bottom flask. A solution of iso- 119 butylmercaptan (aldrich,1.5 9, 0.017 mole) and KOH (1.09, 0.018 mole) in 95% Ethanol (100 ml) was then added dropwise. The reaction mixture was refluxed for 1.5 hours with stirring. The reaction mixture was poured into CHCI3 (150 ml). The solution was then washed with saturated Na2003 / H2O solution (3 x 100 ml) and extracted with CHCI3 (2 x 100 ml). The organic layer was washed by saturated Na2003/ H20 solution (2 x 100 ml). The organic layer was separated and dried over MgSO4. Solvent was removed under reduced pressure. A liquid (3 9) was obtained by distillation (186°C / 0.5 mm); The reddish color was removed by run the liquid through silica gel column. 1H NMR (300 MHz) 8 0.925(t, J = 7.42 Hz, 3H), 1.24(d, J = 6.78 Hz, 3H), 1.56(m, J = 7.11, 2H), 2.59(qt, J = 6.20 and J = 6.20 Hz, 1H), 3.77(s, 2H), 7.45(qq, J g 7.97 and 1.35 Hz, 4H), 7.57(tt, J = 7.53 and J = 1.40, 1H), 7.76(tq, J = 8.27 and J = 1.31 Hz, 4H) 130 NMR (75 MHz, 00013)510.94, 20.23, 29.20, 34.49, 41.06, 126.39, 128.85, 130.11, 130.52, 132.48, 136.28, 137.87, 144.15, 196.67 IR (CCI4) v 3078, 3062, 3031, 2969, 2928, 2883, 1662, 1606, 1448, 1317, 1302, 1277, 1176, 937 cm-1 MS (EI) m/e 264 (M+, 100), 255, 240, 226, 211, 164, 185, 167, 152, 105, 90, 77 o-Aminobenzophenone (Aldrich, 99, 0.045 mole) was dissolved in acetonitrile (Baker, 75 ml) in a 250 ml round bottom flask. lodomethane (Baker, 309, 0.21 mole) and K2003 (Baker, 189, 0.13 mole) were then added into the solution. The solution was refluxed for 17 hours. A white solid was precipitated. The reaction mixture was allowed to cool down to room temperature. The solution was filtered by suction filtration. White solid ( 4.59, 27% yield) was obtained and recrystallized from ethanol. The product was identified as o- Benzoyltrimethylanilinium iodide. by its spectroscopic data. The filtrate above $8 un ylE 01 945 120 was poured into 100 ml water and extracted with methylene chloride (3 x 70 ml). The organic layer was washed with distilled water (2 x 50 ml) and finally with saturated sodium bicarbonate solution (2 x 50 ml). The solvent was removed under reduced pressure to afford a yellow liquid. A yellowish liquid (1.59, 15% yield) was obtained by distillation (117°C/2mm). This product was identified as o-Benzoyldimethylaniline by its spectroscopic data. WWII-1mm mp 174-176°C- IR (0H30N) v 3400-3650(broad), 3060, 2926, 1666 (0:0), 1597, 1262, 1063, 949, 925 MS (EI) m/e 225,208,193,142,127,105,91,77 (100) Mass (NBA + FAB, Positive) 240, 224, 208, 194, 165, 148, 107 1H NMR (300 MHz, 0030N) 5 3.63 (s, 9H, CH3), 7.47(dd, J = 1.71 and J .- 7.63 Hz, 1H), 7.58 (tt, J = 1.65 and J = 7.74 Hz, 2H), 7.68( dt, J = 0.95 and J = 7.57 Hz, 1H), 7.78 (m, 2H), 7.90 (dd, J = 1.31 and J = 6.36 Hz, 2H), 6.02 (dd, J = 6.73 and J . 0.76 Hz, 1H) 130 NMR ( 75 MHz, 0030N) 5196.2 (C=O), 144.36, 137.2, 136.7, 134.4, 133.5. 132.8, 132.4, 131.6, 130.6, 123.6, 59.4 (CH3) -E l I' II I 1' MS (EI) m/e 225(M'i'), 208, 193, 148,105, 91 77 1H NMR (300 MHz, 00013) 52.66 ( s, 6H ), 6.88(td, J = 7.42 and J = 0.96 Hz, 1H), 6.97 (d, J = 8.30, 1H), 7.30 (dd, J = 7.69 and J = 1.58 Hz, 1H), 7.40 (11, J 3 7.14 and J = 1.16 Hz, 3H), 7.55-7.60 (m, 1H), 7.81 (dt, 7.08 and J = 1.44 Hz, 2H) lR(nujol): 3060, 1660, 1600, 1500 1460, 1360 cm-1 130 NMR (00013, 75 MHz) 5 43.27, 116.55, 126.17, 128.26, 130.11, 130.69, 131.62, 132.83, 135.23, 135.68, 137.92, 198.62 121 o-Benzoyltrimethylanilinium iodide (29, 0.0054 mole) was dissolved in hot distilled water (30 ml) in a 50 ml round bottom flask. A solution of AgBF4 (Aldrich, 1.039, 0.0053 mole) in distilled water (5 ml) was added dropwise into the flask. White precipitate appeared. The reaction mixture was filtered by suction filtration. The water solution was allowed to cool down to room temperature and white crystals (1.59, 85% yield) were obtained. Recrystallization from ethanol afforded white crystals. mp 240-241 °C. MS (FAB, MF) 240(positive), 206 MS (EI) m/e 225 (positive part - CH3), 208, 193, 148, 105, 91, 77 IR (0H30N) v 3631 (b), 3544 (b), 3130, 3063, 2987, (C=O) 1669, 1597, 1493.1262,1257,1053,643,771 cm-1 1H NMR (500 MHz, 0030N): 5 3.6 (s, 9H), 7.5 (dd, J = 1.72 and J =- 7.76 Hz, 1H), 7.6 (1, J = 7.97 Hz, 2H), 7.7 (1, J = 7.54 Hz, 1H), 7.76 (11, J = 7.32 and J < 1 Hz, 1H), 7.79 (dt, J = 1.72 and J = 7.32 Hz, 1H), 7.9 (dd, J = 1.51 and J = 6.62 Hz, 2H), 8.0 (d, J = 8.62 Hz,1 H) 130 NMR (0030M, 75 MHz) 5 197.4 (C=O), 144.6, 136.7, 136.1, 133.9, 133.1, 132.3, 131.8, 131.1, 130.0, 123.0, 59.2 UV (MeOH/EtOH, 100:10) 256.4max(17120), 2955d(1316), 333max(95), 313(168), 366(22.8) UV (acetonile) 366(17.9) - - - ' ' ' - 2-Aminobenzophenone (Aldrich,19, 0.005 mole), benzyl chloride (Fisher, 1.9 g, 0.015 mole) and sodium iodide (001, 0.22 9, 0.0015 mole) were placed into a 100 ml round bottom flask. Acetonitrile (Baker, 30 ml) and sodium carbonate (Baker, 1.59 9, 0.015 mole) were then added into the flask. The solution was stirred and refluxed for 20 hours. The reaction mixture was cooled in an ice bath and filtered by suction 122 filtration. The filtrate was then distilled in vacuum. The residue was a yellow oil. Yellowish crystals (0.59, 27%) were recrystallized from methanol. mp 590-60 °C. IR (CCI4) v 3066,3030, 2845, 2816, 1666 (C=O), 1595, 1501,1485,1450,925 cm'1 MS (EI) m/e 377 (M+), 286 (100), 208,180,167,105,91,77 1H NMR (500 MHz, CDCI3) 8 4.0 (s, 4H), 6.8 (d, J = 6.43 Hz, 4H), 7.0 (d, J = 6.04 Hz, 1H), 7.1 (m, 7H), 7.4 (m, 2H), 7.44 (11, J = 7.43 and J < 1.0 Hz, 2H), 7.6 (11, J -.- 7.43 and J < 1.0 Hz, 1H), 7.6 (dd, J = 6.43 and J = 1.20 Hz, 2H) 130 NMR (75 MHz, 00013) 5 199.1 (0:0), 150.0, 136.3, 137.2, 134.5, 132.8, 130.7, 129.7, 129.6, 128.7, 128.5, 128.0, 127.0, 122.1, 121.6, 56.5 (CH2) uv (MeOH/EtOH, 100:10) 256max(21101), 353m3x(1091), 313(1067), 366(1077). .-::. . - “he. ._.".: ... ...: .-: (.1'. O- Benzoyl-N,N-dibenzylaniline (29, 0.0053 mole) was dissolved in benzene and hydrochloric acid gas generated by heating 37% aqueous hydrochloride (001, 30 ml) in a round bottom flask was bubbled through the solution. A solid precipitated and collected by suction filtration. A yellowish solid was recrystallized form ethanol (1.8g, 80% yield). mp 123-125 °C. IR (0H30N): v 3626 (broad), 3550 (broad), 3065, 3042, (0:0) 1662, 1643,1597 0111'1 MS (FAB, MP) 378 (100, positive part),300,286,270,208,91 MS (El) m/e 377,359, 267, 266 (100), 270. 256,208, 196, 180, 167, 152, 105, 91, 77 123 1H NMR (500 MHz, 0030N) 5 4.76 (b, 4H), 7.16 (q, J = 7.42 Hz, 6H), 7.19-7.43 (m, 9H), 7.42 (1, J = 7.48 Hz, 2H), 7.64 (1, J = 7.41 Hz, 1H), 7.80 (d(b), J = 60.16 Hz, 1H) 130 NMR (75 MHz, 0030N) 5 61.86, 125.67, 126.64, 129.76, 129.66, 130.44, 131.00, 131.99, 133.63, 134.99, 137.80, 199.51 (four missing aromatic carbons may overlapped with other aromatic carbons) uv (MeOH/EtOH, 100:10) 249max(18276), 359,113,.(726), 313(889), 366(720). UV (acetonitrile) 366max(936). Q_Bg_nz.QxJ_N_bg.nuiamiing. was prepared by Sn2 reaction of o- aminobenzophenone and one equivalent benzyl chloride. 0- Aminobenzophenone (Aldrich, 2.09, 0.01 mole), benzyl chloride (Fisher, 1.39, 0.01 mole), 0.59 sodium iodide (CCI, 0.59, 0.003 mole) and 1.09 sodium carbonate (Baker, 1.09, 0.0094 mole) were added into a 100 ml round bottom flask. Acetonitrile (Baker, 30 ml) was then added. The reaction mixture was stirring and refluxed for 5 hours. The reaction mixture was then cooled in ice bath for 5 min. and filtered by suction filtration. The solvent was removed from filtrate under reduced pressure. Recrystallization of the residue from EtOH yielded white crystals (1.29, 41% yield). mp 79°-80°C. 1H NMR (CDCI3, 300 MHz) 8 4.49 (d, J = 5.79 Hz, 2H), 6.51 (td, J = 7.12 and J = 1.04, 1H), 6.72 (d, J = 8.24, 1H), 7.20-7.65 (m,10H), 7.60 (d, J = 8.27 Hz, 2H) 130 NMR (75 MHz, 00013) 5199.4, 151.3, 140.4, 136.3, 135.4, 135.0, 130.8, 129.1, 128.7, 128.0, 127.3, 127.2, 117.7, 114.4, 112.3, 47.2 IR 3320(b), 3085, 3068, 3035, 2936, 2850, 1628 (C=O), 1603, 1576, 1520, 1255, 937(om-1) MS (EI) m/e 267 (M+),270,210,196,180,167,152,106,91,77 124 W139 0- Methylthiobenzophenone (1.39, 0.0057 mole), methylene chloride ( Mallinckrodt, 20 ml) and iodomethane (Baker, 2.0) were placed in a 100 ml round bottom flask. The solution was cooled to -78°C. A9BF4 (Aldrich, 1.09, 0.0051 mole) was added and the reaction mixture was kept under N2 overnight at room temperature. The solution was filtered by suction filtration. The solid was then washed with CH3CN (30 ml) and filtered. The two filtrates were combined. The solvent was removed under reduced pressure and a white solid (1.19, 59%)) was obtained. White crystals were recrystallized from EtOH. m.p191°-194°C. 1H NMR (0030N, 300 MHz) 53.19 (s, 6H), 7.61 (1, J a 7.42, 2H), 7.77 (11, J = 7.45 and J = 1.26 Hz, 1H), 7.80-7.90 (m, 4H), 7.92-6.03 (m, J = 3.02 Hz, 1H), 6.16 (d, J = 7.62 Hz, 1H) MS (NBA + FAB) 243, 213 IR (KBr) v 3299, 3089, 3026, 3010, 2984, 2973, 2936, 2910, 1645, 1595, 1431, 1280, 1037, 929 130 NMR (75 MHz, 0030N) 5 29.36, 126.31, 130.34, 130.66, 132.31, 134.20, 134.76, 135.87, 136.93, 140.59, 196.77 (one missing aromatic tertiary carbon may overlapped with another aromatic tertiary carbon). WM o-aminobenzophenone (Aldrich. 2.0 g) was dissolved in benzene (EM, 50 ml). HCI gas was bubbled though the solution for 30 min. The reaction mixture was filtered to give a white solid (2.09). Recrystallization of the solid from ethanol afforded white crystals m.p175-178 °C. 1H NMR (CD30N, 300 MHz) 53.60 (s), 6.91 (td, J = 7.39 and J = 1.19 Hz, 1H), 7.10 (dd, J = 6.52 and J = 1.22, 1H), 7.40-7.55 (m, 4H), 7.55-7.66 (m, 3H) 125 MS (FAB, Positive) 198 IR (KBr) n 3036, 3200-2800(b), 2559, 1664, 1626, 1597, 1493, 1298, 93 13C NMR (75 MHz, CD30N) 8 124.27(b), 125.70 (b), 129.89, 131.23, 134.23, 134.97, 135.56, 199.15 (three missing aromatic carbons may overlapped in the broad peaks) 81330001193 LEhmocbemicaLGIasswaLe All glassware used were rinsed with acetone, then with distilled water and boiled in a solution of alconox laboratory detergent in distilled water for 24 hours. The glassware was carefully rinsed with distilled water, and boiled in the distilled water for 3 days, with the distilled water changed every 12 hours. After the final distilled water rinse, the glassware was dried in an oven reserved for photochemical glassware at 150°C. Ampoules used for irradiations were made by heating 13 x 100 mm pyrex test tubes (previously cleaned by the procedure described above) approximately 2 cm from the top with an oxygen-natural gas torch and drawing them out to an uniform 15 cm length. 2W5 All solutions were prepared either by directly weighing the desired material into volumetric flask or by dilution of a stock solution. Equal volumes (2.8 ml) of sample were placed via syringes into each ampoule. internal standards used for CC and HPLC analyses were weighed with the ketone starting material. 126 W Filled tubes were attached to a vacuum line with a diffusion pump. These tubes were arranged on a circular manifold equipped with twelve vacuum stopcocks each fitted with size 00 one-hole rubber stoppers. The sample tubes were frozen to liquid nitrogen temperature and evacuated for 10 minutes. The vacuum was removed and the tubes were allowed to thaw at room temperature with stopcocks closed. This freeze-pump-thaw cycle was repeated three times. The tubes were then sealed with an oxygen-natural gas torch. I I I' l' | All samples for kinetic measurements were irradiated in parallel with actinometer solutions in a Merry-Go-Round apparats immersed in a water bath at approximately 25°C. A water cooled Hanovia medium pressure mercury lamp was used as the irradiation source. An alkaline potassium chromate solution (0.002 M K20r04 in 1% aqueous potassium carbonate) was used to isolate the 313 nm emission band. A Coming CS 7-37 Filter was used for 366nm emission band. Preparative scale photolyses were performed using a Hanovia 450-watt medium pressure lamp filtered through a pyrex tube. Ketones were dissolved with the chosen 60 ml solvent in a 25 x 200 test tube. A quartz cooling jacket was inserted. The sample was degassed by bubbled argon through it about 10 minutes and irradiated at room temperature. unalxsimmnedum Analysis by HPLC were performed on a Beckman 332 Gradient Liquid Chromatography System equipped with a Perkin-Elmer Lc-75 Ultraviolet-visible detector and a Dupont 860 Column compartment. An altex Ultrasphere Si 127 absorption Phase column was used. the HPLC system was connected to a Hewlett-Packard 6080 integration Recorder. Analysis by 00 was performed on a Varian Aerograph 1400 or 3400 Gas Chromatography equipped with a flame ionization detector. The 00s were connected to either a Hewlett-Packard 3393a of 3392a integrating Recorder.Three types of columns have been used for CC: Magabore DB-1with 15 meters in length, Magabore DB-210 with 15 meters in length and Magabore DBWAX with 30 meter in length. ECIII' i I 'll Quantum yields were calculated with the following equation, <0: [01/ l where [C] is the concentration of the compound being measured and l is the intensity of light absorbed by samples. The intensity of light was determined by valerophenone actinometry. Thus a degassed 0.1 M valerophenone solution was irradiated in parallel with the samples being analyzed. Upon completion of the irradiation the valerophenone sample was analyzed for acetophenone, using the following equations, [AP] =RIISidIAap/AStd Where [AP] is the concentration of acetophenone, Rf is the response factor for acetophenone, Aap is the integrated area for acetophenone, [Std] is the concentration of the added internal standard, and AStd is the integrated area for the internal standard. 128 The intensity of light absorbed by each sample, in ein I'1 can be calculated from the acet0phenone concentration knowing that (D is 0.33 for acetophenone, l = [acetone] / 0.33 The response factors for each compound on CC or HPLC were obtained by the following equation, Fif=([Cl/[Std])(AStd/AC) The Rf values for CC and HPLC are listed in table 21 and 22. WW3 1H NMR and 130 NMR were recorded on VXR 300,500 and Gemini-300. CD013 and CD3CN were used as solvents and as internal standard (CD013: d 7.24 ppm for 1H NMR and.77 ppm for 130 NMR; 0030N: 1.93 ppm for 1H NMR and 1.3 ppm for 130 NMR). IR spectra were recorded in a FTIR Nicolet lR/42 Spectrometer in 0014 solutions or as pressed KBr discs. Ultraviolet-visible spectra were recorded on a Shimadzu UV-160 Spectrometer in a 1x1 cm cell. Full spectra were taken in cyclohexane or MeOH/EtOH(100:10). The spectra for irradiation condition were taken in the same solvent as irradiation solvents (benzene or acetonitrile) at 313 nm and 366 nm. Mass spectra were recorded on a Finnigan 4000 GC/MS using El or FAB methods. 129 Phosphorescence spectra were recorded on a Perkin-Elmer MPF-44a Fluorescence Spectrometer. 10'4 M solution of ketone in 1-methyltetrahydro- furen in a NMR tube was used.The tube was inserted into a liquid nitrogen- filled, quartz-windowed Dewar flask placed in the cell chamber. The sample was irradiated and the spectra was recorded on a HP 3329A lntergrator. The X-ray crystal structure was measured by Dr. Ward on a Picker FACS- l automatic X-ray diffractometer. Sample of 1-benzyl, 2, 3-diphenylindole was dissolved in methanol in a vial. The resulted solution was then allowed to leave in dark for 3 days until crystal obtained. The data collections were performed with MoKa radiation ( 3. = 0.71073 A) on a Nicolet P3F diffractometer. The structure were solved by direct methods. The X-ray structure is shown in the result section and the crystallographic parameters are presented in the appendix. Qllll I'II'I'I' III II Most of the photoproducts were prepared by irradiation of 0.01 to 0.1 M solutions of the appropriate ketone in the same solvent as the one used in the analysis procedure. The samples were degassed by bubbling argon gas through the solution. Preparative scale photolyses were performed using a Hanovia 450-watt medium pressure lamp filtered through a pyrex tube. Ketones were dissolved with the chosen 60 ml solvent in a 25 x 200 test tube. A quartz cooling jacket was inserted. The sample was degassed by bubbled argon through it about 10 minutes and irradiated at room temperature. 130 BMW A solution of 0.02 M o-benzylthiobenzophenone and 0.1 M thiophenol in benzene was irradiated. Nitrogen gas was bubbled through the solution for all the time during the irradiation. A 450-watt medium-pressure lamp around by a pyrex filter was used. The irradiation was stopped after 10% starting ketone disappearance. One product was identified as o-mercaptobenzophenone by comparing its retention time with authentic sample prepared below. Another product was identified as toluene by comparing its retention time with authentic sample. WNW o-Fluorobenzophenerte (Aldrich. 2.0 e ) and sodium sulfide (Mallinckrodt, Na2S(H2O)9. 2.4 g) and 60 ml DMF were placed in a 100 ml round bottom flask. it was heated and stirred for 20 hours under argon environment. The reaction mixture was poured into ice water (50 ml)and then 15% HCI aqueous solution was added dropwise until the solution turned acidic. It was extracted with 2 x 100 ml ether. The other layer was washed by 2 x 100 ml 10 % KOH / H2O solution. The water layer was acidified and extracted with 2 x 100 ml ether. Solvent was removed under reduced pressure. A yellow liquid (1.0 g) was obtained. The product was further purified by passing though silica gel column chromatography (hexane / ethyl acetate). MS (E1) m/e 214 (100), 197, 184, 149, 137, 105,77 IR (CCI4) v 3084, 3063, 3026, 2565 (SH), 1655 (C=O), 1599, 1448, 1433, 1317, 1298, 937, 923. 1H NMR (300 MHz, CDCI3) 8 4.20 (s, 1H), 7.22 (td, J = 7.51 and J = 1.13 Hz, 1H), 7.30-7.50 (m, 4H), 7.59 (tq, J = 7.54 and J = 1.35 Hz, 1H), 7.78 (m, 2H), 7.86 (dd, J .- 7.94 and J = 0.95 Hz, 1H) 131 13C NMR (75 MHZ, CDCI3) 8 125.77, 128.14, 128.66, 130.41, 131.25, 132.15, 133.224, 136.92, 137.54, 139.59, 196.31 o-(Benzylthio)benzophenone (0.5 9) was dissolved in 100 ml benzene. The solution was irradiated 72 hours until 100% ketone conversion by 60. One product was identified as toluene by comparing its retention time with authentic sample.The solvent was removed under reduced pressure. The product was separated by silica gel chromatography column with hexane and ethyl acetate as eluent. The product was identified as thioxanthen-9-one by its spectrometric data. mp 208-210°C. 1H NMR (300 MHz, 00013) 5 7.46(1, J = 6.53 Hz, 1H), 7.58(m, 2H), 6.60 (d, J = 6.06 Hz, 1H) 130 NMR (75 MHz, 00013) 5 125.96, 126.30, 129.24, 129.86, 132.26, 137.27, 200.96 IR (0014) v 1650,1590, 1460, 1340 cm-1 MS (EI) m/e 212 (100), 184, 139, 108, 79, 69 WNW o-(Benzylthio)acetophenone ( 39 ) in 500 ml purified benzene was irradiated after bubbling with argon for 10 min. The irradiation underwent for 24 hours. A 450-watt medium-pressure lamp around by a pyrex filter was used. Toluene and bibenzyl were identified by comparing the retention times with authentic samples. Two products were collected by flash column Well bubl med triad Drod 132 chromatography. The products were identified by their spectrometric data as o- mercaptoacetophenone and 2,2’-dithiodiacetophenone. W 1H NMR (300 MHz,CDCI3 )5 2.61( s, 3H), 4.44 ( s, 1H ), 7.18(m, 1H), 7.29 ( m, 2H ),7.86 ( d, J = 7.72 Hz, 1H) 130 NMR (75 MHz, 00013) 5 27.73, 124.67, 131.64, 131.75, 132.30, 132.71, 137.57, 198.85 MS (El) m/e 152,137,109 IR (0014) v 1670, 1590, 1560, 2300, 2690(SH), 3030 cm-1 1H NMR ( 300 MHz,CD3CN) 5 2.45(s,6H), 7.34(d1, J = 1.46 and J = 7.54 Hz, 2H), 7.45(dt, J .- 1.44 and J = 8.03 Hz, 2H), 7.74(dd, J = 1.56 and J = 7.78 Hz, 2H), 6.06(dd, J = 1.47 and J = 7.69 Hz, 2H) 130 NMR (75 MHz, 00013) 5 27.45, 125.29, 126.47, 131.44, 132.96, 134.54, 140.65, 199.04 MS (EI) m/e 302,151 IR (0014)3050, 2300, 1670, 1590, 1560, 900 om-t WWW p-(Benzylthio)benzophenone (6.29) was added into a quartz immerssion well. 500 ml 1:1 benzene/hexane mixture was added. Nitrogen gas was bubbled through the solution for all the time during the irradiation. A 450-watt medium-pressure lamp around by a pyrex filter was used. After 1.5 hours irradiation, HPLC shown that 90% of the starting ketone was converted. Two products were detected by GC and HPLC. The solvent was removed under 133 reduced pressure. A yellow solid was separated by using silica gel column chromatography with hexane/methylene dichloride. The product was identified by its spectroscopic data as 4,4'-dithiodibenzophenone. Another product was identified by comparing the retention time with authentic sample on 00 as bibenzyl. I I' I'll' II I II -BESI I 1 H NMR (300 MHz, 00013) 5 7.46 (1, J = 7.90 Hz, 2H), 7.57 (m, 3H), 7.76 (d, J = 6.27 Hz, 4H) 130 NMR (75 MHz, 00013) 5 126.07, 126.53, 130.06, 131.07, 132.73, 136.39, 137.55, 141.90, 196.02 MS (EI) m/e 426(M+), 394, 349, 245, 214, 185,152,136,108,77(base) IR (CCI4) v 3089, 3062, 3031, 2957, 2925, 2857, 1662, 1587, 1550, 1273, 937, 922 p—(Benzylthio)benzophenone (0.44229) was added into 50 ml volumetric flask and benzene was added to the volume. 3 ml of the solution and 0.1 ml HSPh were transferred to each of 10 photolysis tubes . The samples was degassed and sealed using the same degassing procedure described above. The samples was then irradiated at 313 nm for 24 hours at merry-go round apparatus. All the solutions were combined and solvent was removed under reduced pressure. Two products were separated by silica gel chromatography column with hexane / benzene as eluent. One product was identified as 4,4'- dithiodibenzophenone by compare the retention time with the sample above on HPLC and 00. Another product was identified by its spectroscopic data as p- mercaptobenzophenone. WWW MS (EI) m/e 214, 137, 105, 99, 77 134 IR (0014) 3030, 2570 (S=O), 1650 (C=O), 1590, 1490 om-1 1H NMR (300 MHz, 00013) 5 3.6 (s, 1H), 7.3 (d, J = 7.6 Hz, 2H), 7.5 (d, J = 7.6 Hz, 2H), 7.6 (1, J = 7.2 Hz, 1H), 7.7 (d, J = 7.2 Hz, 2H), 7.8 (d, J = 7.6 Hz, 2H) 0.02 M solution of p-(t-butylthio)benzophenone in benzene was irradiated. Nitrogen gas was bubbled through the solution for all the time during the irradiation. A 450-watt medium-pressure lamp around by a pyrex filter was used. The irradiation was stopped after 90% starting ketone disappearance. One product was identified as 4,4'-dithiodibenzophenone by comparing its retention time with authentic sample on HPLC. 0.02 M solution of p-(sec-butylthio)benzophenone in benzene was irradiated. Nitrogen gas was bubbled through the solution all the time during the irradiation. A 450-watt medium-pressure lamp around by a pyrex filter was used. The irradiation was stopped after 90% starting ketone disappearance. One product was identified as 4,4'-dithiodibenzophenone by comparing its retention time with authentic sample on HPLC. 135 4-(Benzylthio)acetophenone (19) and HSPh (19) were dissolved in benzene (40 ml) in a test tube. The test tube was sealed with a rubber stopper and oxygen was removed by bubbling argon through the solution for 10 minutes. The reaction mixture was irradiated for 24 hours. A 450-watt medium- pressure lamp around by a pyrex filter was used. Toluene and bibenzyl were identified by comparing the retention time with authentic samples on GC. The solvent was removed from the reaction mixture under reduced pressure. A yellow solid was separated by silica gel column chromatography. The product was identified by its spectroscopy data as 4,4'-dithiodiacetophenone. 1H NMR (300 MHz, 00013) 5 2.55 (s, 3H), 7.54 (d, J = 6.6 Hz, 2H), 7.89 (cl, J = 8.8 Hz, 2H) 130 NMR (75 MHz, 00013) 5 26.34, 126.25, 129.27, 135.95, 142.52, 197.41 MS 302(M+), 267, 270,255, 184, 136, 123, 108, 43(base) IR (0014) v 3075, 3062, 3031, 2957, 2925, 2657, 1689, 1567, 1560, 1356, 1259,1012,954 W The solution of p-bromomethylacetophenone and thiophenol was irradiated at the same condition as the analysis procedure. p- Methylacetophenone was identified by comparing the retention time with authentic sample. 136 W The solution of p-(phenylthio)methylacetophenone and thiophenol was irradiated at the same condition as the analysis procedure. p- Methylacetophenone was identified by comparing the retention time with authentic sample. Wm The solution of m-(phenylthio)methylbenzophenone and thiophenol was irradiated at the same condition as the analysis procedure. m- Methylacetophenone was identified by comparing the retention time with authentic sample. WEBB The solution of m-chloromethylbenzophenone and thiophenol was irradiated at the same condition as the analysis procedure. m- Methylacetophenone was identified by comparing the retention time with authentic sample. 137 W The solution of m-(phenylthio)methylacetophenone and thiophenol was irradiated at the same condition as the analysis procedure. m- Methylacetophenone was identified by comparing the retention time with authentic sample. W The solution of p-bromomethylbenzophenone and thiophenol was irradiated at the same condition as the analysis procedure. p- Methylbenzophenone was identified by comparing the retention time with authentic sample. W The solution of p-phenylthiomethylbenzophenone and thiophenol was irradiated at the same condition as the analysis procedure. p- Methylbenzophenone was identified by comparing the retention time with authentic sample. l7? Wa 138 The solution of p—(t-butylthio)methylbenzophenone and thiophenol was irradiated at the same condition as the analysis procedure. p- Methylbenzophenone was identified by comparing the retention time with authentic sample. The solution of p-(sec-butylthio)methylbenzophenone and thiophenol was irradiated at the same condition as the analysis procedure. p- Methylbenzophenone was identified by comparing the retention time with authentic sample. Emducummflblcmmgmxlbmzopbenone The solution of p-chloromethylbenzophenone and thiophenol was irradiated at the same condition as the analysis procedure. p- Methylbenzophenone was identified by comparing the retention time with authentic sample. W The solution of p-(phenylsufinyl)methylbenzophenone and thiophenol was irradiated at the same condition as the analysis procedure. p- 139 Methylbenzophenone was identified by comparing the retention time with authentic sample. EmdumemmEbenxlmmnxummnxlbenzmhenma. The solution of p-(phenylsufonyl)methylbenzophenone and thiophenol was irradiated at the same condition as the analysis procedure. p- Methylbenzophenone was identified by comparing the retention time with authentic sample. The solution of p-(n-butylthio)methylbenzophenone and thiophenol was irradiated at the same condition as the analysis procedure. p- Methylbenzophenone was identified by comparing the retention time with authentic sample. 0.29 o-Benzoyl-N,N-dibenzylaniline hydrochloride was dissolved in 10 ml CH3CN in a 25 x 200 test tube with a rubber stopper on it. Argon gas was bubbled through the solution to remove the oxygen for 10 minutes. The sample was irradiated by using a 450-watt medium-pressure lamp around by a pyrex filter and monitored by HPLC for 24 hours. 2 products were detected and 140 separated by silica gel column chromatography with CHZClzlhexane as eluent. One product with less retention time was identified as 1-benzyl,2,3- diphenylindole by its spectroscopic data. WWW mp 155-157 00. IR (CCI4) v 3089, 3065, 3034,2917, 2863, 1604, 1496, 1462, 1363, 1215,1030; MS (FAB) 359 (100), 268, 91 1H NMR (500 MHz, CD3CN) 85.3 (s,2H), 6.9(d, J = 7.33 Hz, 2H), 7.2-7.4 (m,16H), 7.7(dt, J = 7.54 and J < 1.0 Hz,1 H) 130 NMR (75 MHz, 00013) 5 47.46, 110.63, 111.55, 115.60, 119.87, 120.57, 122.52, 125.75, 126.30, 127.34, 127.55, 128.34, 128.57, 128.85, 130.10, 131.27, 131.98, 135.32, 137.19, 138.10, 138.33 Spectroscopic data for X—ray structure is given in table 72 in Appendix part. EIII -B ll'lll'l" Ilil II 0.1 g o-benzoyltrimethylanilinium tetrafluoroborate was placed in a test tube. 10 ml CH3CN was added. Argon was bubbled through the solution to remove the oxygen for 10 min. The reaction mixture was irradiated for 2 hours until 95% conversion of starting ketone. The solvent was removed under reduced pressure. White crystals were recrystallized from methanol. The product was identified by its spectroscopic data as 1,1-dimethyl,3-hydroxy,3- phenyldihydroindolium tetrafluoroborate. -._“: 1 -1 , .A -..;, .. ._ .H.“ ; ,_ _. ... . 3 11: ED; infinig.) mp 194-195 °C. IR (KBr) v 3483 (OH, strong ), 1477, 1466, 1076. 1H NMR (500 MHz, 0030N) 5 7.8(d(broad), J = 6.19 Hz, 1H), 7.7 (td, J = 8.19 and J = 1.29 Hz, 1H), 7.6 (10, J = 7.54 and J = 1.06 Hz, 1H), 7.5-7.4(m, 5H), 7.3 141 (dd, J = 1.08 and J = 7.76 Hz, 1H), 4.77 (d, J = 1.29 Hz, OH), 4.36 (d, J = 12.50 Hz, 1H, CH2), 4.11 (d(broad), J = 12.71 Hz, 1H, CH2), 3.7 (s, CH3), 3.6 (s, CH3). Decoupling experiment shows that 4.11 is coupled with 4.38 and 4.77, addition of D20 to the sample causes disappearance of 4.8 and sharping 4.1 130 NMR (125 MHz, CD3CN): 5 146.7, 141.2, 139.6, 133.1, 132.9, 129.8, 129.7, 127.5, 127.3, 116.7, 81.5 (CH2), 61.3 (COH), 59.7 (CH3), 55.6 (CH3) MS (FAB, MF) 240 (positive). W The solution of 0.02M p-bromobenzophenone and 0.05 M thiophenol was irradiated at 313 nm. Benzophenone was identified by comparing the GC retention time with authentic sample. The solution of 0.02M 3-bromo-4-methoxyacetophenone and 0.05 M thiophenol was irradiated at 313 nm. p-methoyxacetophenone was identified by comparing the HPLC retention time with authentic sample. DIII IIII . Clll' The calculations were performed on an Macintosh ll computer. PCMODEL version 2 was used for molecular mechanics calculations. This program uses MMX force field with the pi VESCF calculations. 142 MMX is an advanced version of MM2 force field by N. L. Allinger and pi VESCF which is developed from MMP1(QCPE-318) also by N. L. Allinger. These modifications were completed by J. J. Gajewski and K. E. Gilbert. This program was distributed by Serena Software, Box 3076, Bloomigton, IN 47402- 3076. One of the two available dihedral angles was used to obtain the minimized conformations. The dihedral drive was performed by calculating each dihedral angle rotating around a certain bond. The calculation was done in the following process. The structures needed to calculated were made with PCMODEL input mode. All the aromatic carbons, carbonyl carbonln and carbonyl oxygen were selected as pi atoms. Sulfur atom was not selected as pi atom. In the input mode, the bond and angles for rotation are chosen by select D-DRV. Calculations were done in the minim mode. Parameters were entered by choosing the following choices. 1. Electrostatic interaction (ndc = 4 mmx88 only). 2. Set dielectric constant 1.5. 3. Are there any constants to be read in? n 4. Dihedral angle is endocyclic? n 5.Set for planar pi-system? n 6.singlet rhf calc. 7. Start geometry optimization after full SCF. After calculation, enter 0 to save all the structures calculated and minimized energies in a named file. 143 APPENDIX This section contains the raw experimental data, such as quantum yield measurements and Stern-volmer quenching studies. Analysis conditions, concentrations of the materials used are provides. 144 Table 19. Values of the Response Factors in GC Analysis. Std / Compound Column /Condition RF. C16 / a010phenone DB-wax/ 120°C 2.23 015 / dibenzyl 06-1 / 15000 1.26 C7H14 / toluene DB-1 /RT 1.09 020 / o-BzSAP DB-1a 1.997 C20 / o-HSAP DB-I a 3.398 C13Ph / o-HSBP DB-1 /180°C 2.60 C24 / o-BzSBP DB-I /230°C 1.65 026 / p-MeBP 06-210b 1.336 025 / p—BuSCH2BP DB-210° 1.64 a int T130° C,final T 155°C, rate 12°C / min. b init T 80°C, init col hold time 2.00 min, final T #1: 170°C, rate:50°C / min.,hold time 4.00min. Final temp #2: 230°C, rate: 50°C / min., hold time: 21 min. 145 Table 22. Values of the Response Factors in HPLC Analysis. Std / Compound Column R. F. MeBz / p-BzSBP Microsorb Sia 0.154 MeBz / (p-BPS)2 Microsorb Sial 0.0364 MeBz / p-BzSAP Microsorb Si° 0.192 MeBz / (p-APS)2 Microsorb Si° 0.0461 Cl20NPh / PhSO2CH2BP Microsorb Si° 0.0367 Cl2CNPh / p-MeBP Microsorb Sid 0.0337 CI2CNPh / PhSOCH2BP Microsorb Sif 0.025 01082 / o-BzNBPzHCl Reverse phase CN HPLC° 0.0142 C1oBz/ 1-Bz,2,3-Ph2indole Reverse phase CN HPLC° 0.066 CeBz/AP Microsorb Si HPLcd 1.09 MeBz/p-MeAP Microsorb Si HPLcd 0.77 MeBz/p-MeBP Microsorb Si HPLcd 0.0719 MeBz/m-MeAP Microsorb Si HPLcd 1.35 MeBz/m-MeBP Microsorb Si HPL09 0.175 MeBz/p-BrCH2AP Microsorb Si HPLcd 0.156 MeBz/p-PhSCH2AP Microsorb Si HPLcd 0.13 MeBz / p-PhSCH2BP Microsorb Si HPLC° 0.043 MeBz/p-t-BuSCHzBP Microsorb Si HPLcd 0.0575 MeBz/p-sec-BuSCH2BP Microsorb Si HPLcd 0.0667 MeBz/m-PhSCH2AP Microsorb Si HPLcd 0.161 MeBz/m-CICH2BP Microsorb Si HPLCQ 0.188 MeBz/m-PhSCH2BP Microsorb Si HPLcd 0.144 MeBz/p-CICHzBP Microsorb Si HPLcd 0.0654 146 Table 20 (Cont'd.). MeBz/p-BrCH2BP Microsorb Si HPLcd 0.0462 Mebz/p-t-BuSBP Microsorb Si HPLCa 0.0567 MeBz/(p-SBP)2 Microsorb Si HPLCa 0.0359 MeBz/(p-SBP)2 Microsorb Si HPLcd 0.0366 MeBz/p-sec-BuSBP Microsorb Si HPLcd 0.176 MeBz/o-BzSAP Microsorb Si HPch 0.113 MeBz/(o-APS)2 Microsorb Si HPch 0.074 a Hexane Iethyl acetate (95 / 5), Rate: 1.5ml / min. @ 270nm. b Hexane /ethyl acetate (90 / 10), Rate: 1.5ml / min., @ 270nm. C Time Flow Rate Hexane% Duration Tme 0 1.0 100 0.5 6 1.5 85 0.5 16 1.5 100 0.5 30 1.0 100 0.5 end @270 nm d Hexane/AcOEt (95/5) 1.0 ml/min. @270 nm. 9 H2O / CH30H (5 / 95). 1.0 ml / min., @270 nm. 1 Time Flow Rate Hexane% Duration Tme 0 1.0 98 0.5 8 1.0 50 0.5 25 1.0 98 0.5 31 end @270 nm 9 Hexane/AcOEt (97/3) 1.0 ml/min. @270 nm. 147 Table 21. Quenching of 4,4’-Dithiodibenzophenone Formation upon Irradiation of p-(Benzylthio)benzophenone. th = 125 HPLC analysis: Ultrasphere Sl Hexane / ethyl acetate ( 95 : 5) 1.0 ml / min, @ 270nm Sample [Naphethalene] x 103 [(p-SBP )2 / MeBz [A can» #1 0 1.172 1.0 #2 4.009 0.773 1.516 #3 6.019 0.597 1.963 #4 12.03 0.477 2.457 #5 16.04 0.366 3.036 [p-BzSBP] = 0.01989M, [MeBz] = 0.07051 M, 2 hours, 366nm. Table 22. Quantum Yields for Irradiation of p-(Benzylthio)benzophenone. Compound (Compound / Std)A Concentration (b Dibenzyl 0.495 0.00109 0.15 p-BzSBP 2.821 0.01686 0.40 (p-BPS)2 0.655 0.00121 0.17 [p-BzSBP] = 0.01973 M. [MeBz] = 0.03661 M. [016] = 0.001722 M. 3 hours, 313 nm. RF: MeBz/p-BzSBP 0.154; C15/Dibenzyl 1.28; MeBz/(p-BPS)2 0.0364, VP actinometer: [VP] = 0.1004 M. [03le = 0.00604 M. (AP/0382M = 0.358. [AP] = 0.00236 M. lo = 0.00714 ein 1-1. 148 Table 23. Quantum Yields for Irradiation of p-(t-Butylthio)benzophenone.a HPLC analysis: Microsorb-Si Hexane / Ethyl acetate 95: 5 @270 nm Flow Rate 1.5 ml / min. Compound (Compound / MeBz)A Concentration <0 p-t-BuSBP 6.553 0.01803 0.37 (p-SBP)2 0.732 0.00128 0.18 alp—t-BuSBP] = 0.02061 M, [0362] = 0.04854 M, 3 hours, 313 nm. RF: MeBz/p—t-BuSBP 0.0567; MeBz/ (p-SBP)2 0.0359. VP actinometer: [VP] = 0.09766 M. [CaBz] = 0.00797 M. (AP / CaBz)A =0.263 M. [AP] =- 0.00226 M I0 = 0.00692 ein 1-1. 149 Table 24. Quenching of 4,4’-Dithiodibenzophenone Formation upon Irradiation of p-(t-Butylthio)benzophenone HPLC analysis: Microsorb-Si Hexane / ethyl acetate,@ 270nm, Program Time Flow Rate Hexane% Duration time quc = 683 0 1.3 99 0.5 1 1.3 98 0.5 6 1.3 85 0.5 1 3 1.3 1 00 0.5 20 end Sample [Naphethalene] [(p-SBP)2/MeBz]A rho/<0 #1 0 1.921 1.0 #2 0.0125 1.090 1.76 #3 0.00094 1.265 1 .52 #4 0.00218 0.748 2.57 #5 0.00359 0.597 3.22 #6 0.00531 0.398 4.83 #7 0.00624 0.348 5.52 #8 0.00874 0.287 6.69 [p-t-BuSBP] = 0.01056 M, [MeBz] -.- 0.00979M, 1 hour, 366 nm 15W 150 Table 25. Quenching of 4,4’-Dithiodibenzophenone Formation upon Irradiation of p-(sec-Butylthio)benzophenone. th = 7669 HPLC analysis: Microsorb Si Hexane / ethyl acetate ( 95 :5) 1.0 ml / min, @ 270nm Sample [Naphethalene] x 103 [(p-SBP )2 / MeBz 1A (bol <0 #1 0 0.248 1.0 #2 0.0349 0.208 1.19 #3 0.0698 0.157 1.58 #4 0.116 0.134 1.85 #5 0.233 0.0895 2.77 #6 0.466 0.0613 4.05 #7 0.698 0.0478 5.19 #8 0.931 0.0346 6.82 #9 1.16 0.0343 7.22 #10 1.40 0.0329 7.54 [p-sec-BuSBP] = 0.01003 M, [MeBz] = 0.00992 M, 24 hours, 366nm 151 Table 26. Quantum Yield for Irradiation of p-(sec-ButylIthio)benzophenonea compound (Compound / Std)A Concentration (I) p-sec-BuSBP 5.676 0.00917 0.019b L_(p-BPS)2 0.209 0.0000702 0.0052c a[p-sec-BuSBP] = 0.00979 M. [MeBz] = 0.00918 M. RF: MeBz/ p-sec-BuSBP 0.176; MeBz/ (p-BPS)2 0.0366. VP actinometer: [valerophenone] = 0.1009 M. [0382] = 0.00626 M. b30 hours, 313 nm, (AP/03Bz)A = 1.552, [APltotaI =- 0.01059 M. lo = 0.0321 ein l-1. c10 hours, 313 nm, (AP/CaBz)A = 0.0658, [AP]: 0.00449 M. lo = 0.0136 ein l-i. 152 Table 27. Quenching of 4,4’-dithiodiacetophenone Formation upon Irradiation of p-(Benzylthio)acetophenone Kq'c = 69.9 HPLC analysis: Ultrasphere Si Hexane / ethyl acetate (90 : 10) 1.5 ml / min, @ 270nm Sample [1 -methylnaphethalene] ( (p-APS)2 / MeBz)A (Do / #1 0 1 .328 1.0 #2 0.004501 1.055 1.26 #3 0.01252 0.707 1.88 #4 0.01660 0.618 2.15 #5 0.02672 0.467 2.84 [p-BZSAP] = 0.008629 M, [methyl benzoate] = 0.008144, 3 hours, 3660m Table 28. Quantum Yield for Irradiation of p-(Benzylthio)acetophenone in Benzenea Compound (Compound / Std)A [Compound] <0 dibenzyl 0.434 0.000927 0.16 p-BzSAP 2.166 0.01668 0.47 (p-APS)2 0.740 0.00137 0.24 a[ p-BzSAP] = 0.01944 M. [016] = 0.001669 M, [MeBz] = 0.0401 M, 3 hours, 313 nm. RF: C15/dibenzyl 1.28; MeBz/p-BzSAP 0.192; MeBz/(p—APS)2 0.0461. VP actinometer: [valerophenone] = 0.1004 M. [03le = 0.00604 M. (AP/0382M = 0.287. [AP] = 0.00189 M. lo = 0.00573 ein l'1. 153 Table 29. Quenching of Toluene Formation upon Irradiation of o-(Benzylthio)benzophenone. Kq'c = 2.07 :t 0.1 GC analysis: 1400 varien Gas Chromatography DB-1 magbor column, Room temperature [01a (Toluene / 0m 90 / 01 [01b (Toluene / cm o 101 0 0.460 1.0 0 0.244 1.0 0.0646 0.422 1.14 0.1966 0.176 1.366 0.1635 0.349 1.37 0.441 0.124 1.966 0.2792 0.321 1.50 0.516 0.115 2.122 0.3136 0.301 1.59 0.672 0.0966 2.526 0.3946 0.266 1.79 0.790 0.0924 2.641 0.4637 0.244 1.97 aRun 1: [o-BzSBP] = 0.01995 M, [071.17] = 0.001736 M, [HSPh] = 0.09876M, 43 hours, 366nm °Run 1: [o-BzSBP] = 0.01922 M, (071.71: 0.001703 M, [HSPh] 2 0.04797 M, 6 x 24 hours, 366nm 154 Table 30. Quantum Yields for Irradiation of o-(Benzylthio)benzophenone in Benzenea Compound (Compound / Std)A [Compound] 0 toluene 0.480 0.000909 0.0041 o-BzSBP 2.22 0.01905 0.0041 o-HSBP 0.164 0.000567 0.0026 3] o-BzSAP] = 0.01995 M. [07] = 0.001738 M, [024] = 0.005386 M, [C13Ph] = 0.001351 M, [HSPh] = 0.09876 M, 43 hours, 366 nm. RF: C7/toluene 1.09; 024/o-BzSBP 1.65; C13Ph/o-HSBP 2.60. VP actinometer: [valerophenone] = 0.0902 M. [016] = 0.00662 M. (AP/C15)A = 2.703. [AP] = 0.0399 M, lo = 0.22. 155 Table 31. Quenching of Dibenzyl Formation upon Irradiation of o-(Benzylthio)acetophenone at 366nm th = 11.6 G0 analysis: 3400 varien Gas Chromatography DB-210 magbor column Program: Initial column temp.: 80° 0 Initial col. hold time: 5 min. Final col. temp. 200° 0 Rate: 80°C I min Sample [1 -Methylnaphethalene] ( Dibenzyl / C20)A (Do/<0 #1 0 0.311 1.0 #2 0.02127 0.241 1.29 #3 0.04106 0.186 1.67 #4 0.06007 0.175 1.78 #5 0.08373 0.154 2.02 #6 0.1077 0.137 2.27 [o-BzSAP] = 0.02079M, [020] = 0.001227M, 366 nm. 156 Table 32. Quantum Yield for Irradiation of o-(Benzythio)acetophenonea Compound (compound / Std)A Concentration (b Dibenzyl 0.3046 0.000703 0.018 o-BzSAP 2.5644 0.008650 0.036 (o-APS)2 0.344 0.000760 0.019 a[ o-BzSAP] = 0.01007 M. [MeBz] = 0.02965 M, [C16] = 0.001602 M.18 hours at 313 nm. RF: C16/Dibenzyl 1.28; MeBz/(o-APS)2 0.074; MeBz/o-BzSAP 0.113. [Valerophenone] = 0.09766 M. [0382] =- 0.00797 M. (AP/0382M = 1.515. [AP] = 0.01316 M, lo = 0.0399 ein 1-1. Table 33. Quantum Yield for Irradiation of o-(Benzythio)acetophenonea compound (compound / Std)A Concentration (D o-BzSAP 8.130 0.017696 0.081 o-APSH 0.9364 0.00347 0.064 Toluene 2.265 0.00437 0.081 at o-BzSAP] = 0.02206 M. (07] = 0.001772 M. [020] = 0.001090 M [HSPh] = 0.04927 M, 17 hours at 313 nm RF: C7/toluene 1.09; C2o/o-APSH 3.390; Czo/o-BzSAP 1.997. [Valerophenone] = 0.0997M. [016] = 0.00926M. (AP/C15)A = 0.667. [AP] = 0.0179 M. lo = 0.0543 ein 1-1. Table 34. Quenching of formation of p-Methylbenzophenone from Irradiation of p-(Phenylthio)methylbenzophenonea th = 0.74 GC analysis: 3400 varien Gas Chromatography DB-210 magbor column Initial column temp.: 80° 0, Initial col. hold time: 2 min. Final col. temp. #1 : 170° C, Rate: 50.0°C/min, hold time: 4 min. Final col. temp. #2: 220° 0, Rate: 50.0°C/min, hold time: 21 min. Sample [Naphethalene] ( p—MeBP / 026 )area rho/<0 #1 0 0.480 1.0 #2 0.260 0.407 1.18 #3 0.641 0.332 1.45 #4 0.809 0.290 1.66 #5 0.989 0.267 1.80 #6 1.183 0.240 2.00 #7 1.420 0.233 2.06 #8 1.566 0.221 2.17 #9 1.841 0.209 2.30 a[ p-PhSCHzBP] = 0.005775M, [026] = 0.001774M, [HSPh] = 0.01454M, 1 hour at 366nm 158 Table 35. Quantum Yields for Irradiation of p-(Phenylthio)methybenzophenonea HPLC analysis: Microsorb-Si Hexane / ethyl acetate ( 95 : 5) 1.0 ml/min,@270nm I Compound I (p—PhSCH2BP/MeBz)A [ Concentration J <0 I I p-PhSCHzBP l 21.02 I 0.00869 I027 I a[ p-PhSCH2BP] = 0.00962 M, [MeBz] = 0.00961 M, [HSPh] = 0.0514 M, 2.5 hours at 313 nm. RF: MeBz/p-PhSCH2BP 0.043. VP actinometer: [VP] = 0.1003 M. [0382] = 0.00700 M. (AP/0382M = 0.1836. [AP] = 0.00140 M, I0 = 0.00425 ein 1-1. Table 36. Quantum Yield for Irradiation of p-(Phenylthio)methylbenzophenonea GC analysis: 3400 varien Gas Chromatography DB-210 magbor column Initial column temp.: 80° C, Initial col. hold time: 2 min. Final col. temp. #1: 170° C, Rate: 50.0°C/min, hold time: 4 min Final col. temp. #2: 230° 0, Rate: 50.0°C/min, hold time: 21 min Compound (Compound / 026M [Compound] <0 PhSSPh 0.6062 0.001296 0.16 p-PhSCH2BP 1.1057 0.00317 0.27 p—MeBP 0.6559 0.00161 0.19 a[p-PhSCH2BP] = 0.005413M, [026] = 0.001836M, [HSPh] = 0.009073M. RF: 025/ p-PhSCH2BP 1.56; Cze/p—MeBP 1.34; C26/PhSSPh1.164; 10 min., 366nm: 159 Table 37. Effect of Thiophencl Concentration on Quantum Yield for Irradiation of p-(Phenylthio)methybenzophenonea HPLC analysis: Microsorb-Si Hexane / ethyl acetate ( 95 : 5) 1.0 ml / min, @ 270nm Sample [HSPh] ( p-MeBP/MeBz)A Lp-MeBP] <0 #1 0 0.024 0.0000166 0.0091 #2 0.000379 0.276 0.000191 0.105 #3 0.000759 0.397 0.000274 0.136 #4 0.00152 0.606 0.000419 0.230 #5 0.00340 0.483 0.000334 0.184 #6 0.0514 0.672 0.000464 0.255 #7 0.1029 0.687 0.000475 0.261 #8 0.5170 0.564 0.000390 0.215 a[p-PhSCH2BP] = 0.00982 M, [MeBz] = 0.00961 M, 1 hours, 313 nm, actinometer: [VP] = 0.1003 M. [03sz = 0.00700 M. [AP] = 0.000600 M 160 Table 38. Quantum Yields for Irradiation of p-(t-Butylthio)methylbenzophenonea HPLC annalysis: Microsorb-Si Hexane / ethyl acetate ( 95 : 5) 1.0 ml / min, @ 270nm Compound (Compound / MeBz)A Concentration <0 p-t-BuSCH2BP 18.26 0.009880 0.35 p-MeBP 0.806 0.000545 0.18 a[ p-t-BuSCHzBP] = 0.01095 M, [MeBz] = 0.00941 M, [HSPh] = 0.0661 M, 2 hours, 313 nm. RF: MeBz/p-MeBP 0.0.0719; MeBz/p-t-BuSCH2BP 0.0575. VP actinometer: [VP] = 0.1003 M. [03le = 0.00700 M. (AP/CaBz)A = 0.134. [AP] = 0.00102 M. lo = 0.00310 ein 1-1. 161 Table 39. Quenching of p—Methylbenzophenone Formation upon Irradiation of p-(t-Butylthio)methylbenzophenone. HPLC analysis: Microsorb-Si th = 27.6 Hexane / ethyl acetate ( 95 : 5 ) 1.0 ml / min, @ 270nm Sample [Naphethalene] ( p-MeBP/MeBz)A <00/<0 #1 0 0.749 1 .0 #2 0.0146 0.531 1.41 #3 0.0315 0.412 1.82 #4 0.0453 0.347 2.16 #5 0.0663 0.276 2.71 #6 0.0810 0.228 3.29 [p-t-BuSCH2BP] = 0.00879 M, [MeBz] = 0.00985M, [HSPh] = 0.00492 M, 1 hour, 366 nm Table 40. Quantum Yields for Irradiation of 162 p-(sec-Butylthio)methylbenzophenonea HPLC analysis: Microsorb-Si Hexane / ethyl acetate ( 95 : 5) 1.0 ml / min, @ 270nm Compound (Compound / MeBz)A Concentration <0 p-sec-BuSCHzBP 8.441 0.005582 0.38 p-MeBP 1.214 0.000843 0.21 a[p-2-BuSCH2BP] = 0.007114 M, [MeBz] = 0.00966 M, [HSPh] = 0.0732 M, 2.5 hours, 313 nm. RF: MeBz/p-sec-BuSCHzBP 0.0687; MeBz/p-MeBP 0.0719. VP actinometer: [VP] = 0.1003 M. [03le = 0.00700 M. (AP/0382M = 0.1728. [AP] =.- 0.00132 M, I0 = 0.00400 ein 1-1. 163 Table 41. Quenching of p—Methylbenzophenone Formation upon Irradiation of p-(Sec-Butylthio)methylbenzophenone HPLC analysis: Microsorb-Si th = 16.9 Hexane / ethyl acetate ( 95 : 5 ) 1.0 ml / ming 270nm Sample [Naphethalene] ( p-MeBP/MeBz)A <00/<0 #1 0 1 .063 1 .0 #2 0.0694 0.474 2.24 #3 0.1075 0.379 2.80 #4 0.1501 0.305 3.49 #5 0.1726 0.268 3.97 [p-2-BuSCH2BP] = 0.0105 M, [MeBz] = 0.00931 M, [HSPh] = 0.0747 M, 2 hour, 366 nm 164 Table 42. Quenching of p-Methylbenzophenone Formation upon rradiation of p-(n-Butylthio)methylbenzophenone HPLC analysis: Microsorb-Si th = 16.5 Hexane / ethyl acetate ( 95 : 5 ) 1.0 ml / min, @ 270nm Sample [Naphethalene] ( p-MeBP/MeBz)A <0o/<0 #1 0 1 .931 1.0 #2 0.0585 0.981 1 .97 #3 0.0888 0.797 2.42 #4 0.1 186 0.646 2.99 #5 0.1 503 0.553 3.49 #6 0.1947 0.458 4.22 [p-BuS0H2BP] a 0.0150 M, [MeBz] .- 0.00879 M, [HSPh] . 0.0740 M, 2 hour, 366 nm Table 43. Quantum Yield of Irradiation of p-(n-Butylthio)- methylbenzophenone Compound (Compound / 026)A Concentration <0 p-BuSCH2BP 0.936 0.00464 0.36 p—MeBP 0.350 0.00141 0.20 [ p-BuSCH2BP] = 0.00716 M, [026] = 0.00302M, [HSPh] = 0.0133M, 2 hours, 366nm. RF: Cze/p-MeBP 1.336; Cze/p-BuSCH2BP 1.64. VP actinometer: [VP] = 0.09976 M. [C16] = 0.006352 M. (AP/C16)A = 0.1391. [AP] = 0.00197 M 165 Table 44 . Quantum Yield of Irradiation of p-Bromomethylbenzophenone HPLC analysis: Microsorb-Si Hexane / Ethyl acetate ( 95 :5 ) 1.0 ml / min, @ 270nm Compound (Compound / MeBz)A Concentration <0 p-Br0H2BP 33.50 0.0159 0.45 p-MeBP 2.78 0.00206 0.30 [p-BrCHzBP] = 0.0190 M, [MeBz] .-.. 0.0103 M, [HSPh] = 0.0960 M. 2 hours, 313 nm. RF: MeBz/p-BI’CHQBP 0.0462; MeBz/p-MGBP 0.0719. VP actinometer: [VP] = 0.1005 M. [016] = 0.0075 M. (AP/C16)A = 0.1344. [AP] = 0.00224 M, I0 = 0.00661 ein l-i. ‘- - "'-.n_.— 166 Table 45. Quenching of p-MethylbenzophenoneFormation upon Irradiation of p-Chloromethylbenzophenone. kq’t = 11 G0 annalysis: 3400 varien Gas Chromatography DB-210 magbor column Initial column temp.: 80° 0, Initial col. hold time: 2 min. Final col. temp. #1: 160° 0, Rate: 40.0°C/min, hold time: 3.5min. Final col. temp. #2: 18000 0, Rate: 40.0°C/min, hold time: 10 min. Sample [Naphethalene] ( PhSSPh / C26)A <00/<0 #1 0 0.889 1.0 #2 0.037 0.577 1.54 #3 0.088 0.364 2.44 #4 0.161 0.275 3.23 #5 0.378 0.160 5.56 #6 0.524 0.128 6.95 #7 0.650 0.109 8.16 #8 0.733 0.0906 9.81 [p-CICH2BP] = 0.00746M. [024] = 0.001796M, [HSPh] = 0.0171M. 50 min, 366nm 167 Table 46. Quantum Yield of Irradiation of p-Chloromethylbenzophenone HPLC analysis: Microsorb-Si Hexane / ethyl acetate (95:5) 1.0 ml / min, @ 270nm Compound (Compound / MeBz)A Concentration <0 p-CICH2BP 13.73 0.0220 0.48 p-MeBP 0.670 0.000906 0.48 [ p—CICH2BP] = 0.0229 M, [MeBz] = 0.0188M, [HSPh] a 0.0519 M, 1 hour, 313 nm, RF: MeBz/p-CICH2BP 0.0854; MeBz/p-MeBP 0.0719. VP actinometer: [VP] = 0.1016 M. [0382] = 0.01978 M. (AP/CaBz)A = 0.0288. [AP] = 0.000622 M, I0 = 0.00166 ein 1-1. 168 Table 47. Quantum Yield of Irradiation of p-Phenylsulfinylmethylbenzophenone HPLC analysis: Microsorb Si. For p-MeBp: Hexane : EtOAc 95:5, 1.0 ml / min,@270 nm For p-PhSCH2BP: @270 nm Program Time Duration time Flowrate Hexane : EtOAc 0 0.5 1.0 98 : 2 8 2 1.0 50 : 50 25 1 1.0 98 : 2 31 end Compound (Compound / Cl20NPh)A Concentration <0 p-PhSOCHzBP 4.199 0.00271 0.33 p-MeBP 5.358 0.00466 0.35 [ p-PhSOCHzBP] = 0.00725 M, [Cl20NPh] = 0.0258M, [HSPh] a 0.0909M. 4 hours, 366nm. RF: Cl2CNPh/p-PhSOCH2BP 0.025;CI2CNPh/p-MeBP 0.0337. VP actinometer: [VP] = 0.09978 M. [C16] = 0.006352 M. (AP/C16)A = 0.02127. [AP] = 0.00301 M. 169 Table 48. Quenching of p-Methylbenzophenone Formation upon Irradiation of p-Phenylsulfonylmethylbenzophenone. HPLC analysis: Microsorb-Si quc = 515 Hexane I ethyl acetate ( 95 : 5 ) d’p-MeBP = 0.29 1.0 ml / min, @ 270nm Sample [Naphethalene] ( p-MeBP / Cl2CNPh)area <0ol<0 #1 0 2.541 1.0 #2 0.000922 1.605 1 .58 #3 0.00184 1.292 1.97 #4 0.00277 1 .034 2.46 #5 0.00369 0.895 2.84 #6 0.00461 0.739 3.44 #7 0.00553 0.653 3.89 #8 0.00646 0.532 4.77 #9 0.00738 0.560 4.54 [p-PhSOzCHzBP] = 0.00498M, [CI20NPh] = 0.0153M, [HSPh] = 0.0140M. 1.5 hours, 366nm. 170 Table 49. Quantum Yield of Irradiation of p-Phenylsulfonylmethyl- benzophenone HPLC analysis: Microsorb Si 270@ Program Time Duration time Flowrate Hexane : i-propanol 0 0.5 1.0 100 : 0 6 0.5 1.5 85 : 15 1 6 0.5 1.5 100 : 0 30 0.5 1.0 100 : 0 Compound (Compound / Cl2CNPh)A Concentration <0 p-PhSOzCH2BP 5.621 0.004983 0.35 p-MeBP 2.541 0.00149 0.29 [p-PhS020H2BP] = 0.00498M, [Cl20NPh] = 0.0153M, [HSPh] = 0.0140M. 1.5 hours, 366nm. RF: Cl20NPh/p-PhSOzCH2BP 0.0367; Cl20NPh/p-MeBP0.0337. VP actinometer: [VP] = 0.09978 M, [016] = 0.006352 M, (AP/016)A = 0.1047 [AP] = 0.00146 M. lo = 0.00449 ein l-t. Table 50. Effect of Thiophencl concentration on Quantum Yield for 171 Irradiation of p-(Phenylthio)methyacetophenone. HPLC analysis: Microsorb-Si Hexane / ethyl acetate ( 95 : 5 ) 1.0 ml / min, @ 270nm Sample [HSPh] ( p-MeAP/MeBz)A [p-MeAP] <0 #1 0 0.0112 0.000081 1 0.038 #2 0.00381 0.0890 0.000644 0.30 #3 0.0245 0.1040 0.000753 0.35 #4 0.0496 0.1053 0.000762 0.35 #5 0.0904 0.0829 0.000600 0.28 #6 0.505 0.0899 0.000651 0.30 [ p-PhSCH2AP] = 0.00841 M, [MeBz] = 0.00940 M, 1 hours, 313 nm. RF: MeBz/p-MeAP 0.77. VP actinometer: [VP] = 0.1003 M. [03le = 0.00700 M. (AP/CaBz)A = 0.09363. [AP] = 0.0007144 M. I0 =1 0.00216. 172 Table 51. Quenching of p-Methylacetophenone Formation upon Irradiation of p-(Phenylthio)methylacetophenone. HPLC analysis: Normal phase Si th = 0.24 Hexane / ethyl acetate (95:5) 1.0ml / min, @ 270nm Sample [Naphethalene] ( p-MeAP/MeBz)A <00/<0 #1 0 0.110 1.0 #2 0.558 0.0943 1 .136 #3 1.078 0.0871 1 .263 #4 1.678 0.0788 1 .383 #5 2.051 0.0722 1 .151 [ p-PhSCH2AP] = 0.007638M, [MeBz] = 0.01784M, [HSPh] = 0.04112M. 4 hours, 366nm Table 52. Quantum Yield for Irradiation of p-(Phenylthio)methyl- acetophenone HPLC analysis: Microsorb-Si Hexane / ethyl acetate ( 95 : 5) 1.0 ml / min, @ 270nm Compound (Compound / MeBz)A Concentration <0 p-PhSCH2AP 2.976 0.00913 0.31 p-MeAP 0.0589 0.001078 0.35 [p-PhSCH2AP] = 0.01018 M, [HSPh] = 0.05482 M. [MeBz] = 0.02378 M, 2 hours, 366 nm. RF: MeBz/ p-MeAP 0.77; MeBz/p-PhSCH2AP 0.13. 173 Table 53. Quenching of p-Methylacetophenone Formation upon Irradiation of p-Bromomethylacetophenone HPLC analysis: Normal phase Si th < 0.1 Hexane / ethyl acetate (95:5) 1.0ml / min, @ 270nm Sample [Naphethalene] ( p-MeAP/MeBz)A <0ol<0 #1 0 9.45 1 .0 #2 0.1248 10.15 0.93 #3 0.08676 9.42 1 .00 #4 0.4497 9.97 0.95 #5 1.1959 9.61 0.98 [ p-BrCH2AP] = 0.0183 M, [MeBz] = 0.01173 M, [HSPh] = 0.1137 M. 6 hours, 366nm 174 Table 54. Quantum Yield of Irradiation of p-Bromomethylacetophenone HPLC analysis: Microsorb-Si Hexane / ethyl acetate ( 95 : 5) 1.0 ml / min, @ 270nm Compound (Compound / MeBz)A Concentration <0 p-BrCH2AP 9.12 0.0166 0.22 p-MeAP 0.218 0.00197 0.25 [ p-BrCH2AP] = 0.0183 M, [MeBz] = 0.01173 M, [HSPh] = 0.1137 M, 6 hour, 366 nm. RF: MeBz/p-BrCH2AP 0.156; MeBz/p-MeAP 0.77. VP actinometer: [VP] = 0.1006 M. [C16] = 0.00750 M. (AP/015) = 0.290. [AP] = 0.00465 M. 175 Table 55. Quantum Yields of Irradiation of m-(Phenylthio)methylbenzophenone HPLC analysis: Microsorb-Si Hexane / ethyl acetate ( 95 : 5) 1.0 ml / min, @ 270nm Compound (Compound / MeBz)A Concentration <0 m-PhS0H2BP 6.278 0.00863 0.47 m-MeBP 0.854 0.00143 0.39 [ m-PhSCH2BP] = 0.01036 M, [MeBz] = 0.00955M, [HSPh] = 0.0556 M, 2 hours, 313 nm. RF: MeBz/m-PhSCH2BP 0.144; MeBz/m-MeBP 0.175. VP actinometer: [VP] = 0.1016 M. [0382] = 0.01978 M. (AP/03Bz)A = 0.0557. [AP] = 0.00120 M, lo = 0.00364. 176 Table 56. Quenching of m-Methylbenzophenone Formation upon Irradiation of m-(Phenylthio)methylbenzophenone. HPLC analysis: Microsorb-Si th = 40 Hexane / ethyl acetate ( 97 : 3 ) 1.0 ml I min, @ 270nm Sample [Naphethalene] ( m-MeBP/MeBz)A <00/<0 #1 0 1 .085 1 .0 #2 0.0249 0.503 2.1 57 #3 0.0505 0.340 3.191 #4 0.0741 0.270 4.01 9 #5 0.0991 0.215 5.047 #6 0.1229 0.199 5.453 [m-PhSCH2BP] = 0.01016 M, [MeBz] = 0.00925M, [HSPh] = 0.00532 M, 1 hour, 366 nm 177 Table 57. Quantum Yields of Irradiation of m-Chloroxymethylbenzophenone HPLC analysis: Microsorb-Si Hexane / ethyl acetate ( 95 : 5) 1.0 ml / min, @ 270nm Compound (Compound / MeBz)A Concentration <0 m-CICH28P 17.21 0.0306 0.038 m-MeBP 0.292 0.000483 0.036 [ m-CIH2BP] = 0.0311 M, [MeBz] = 0.009448 M, [HSPh] = 0.0546 M, 15 hours, 313 nm. RF: MeBz/m-CICH2BP 0.188; MeBz/m-MeBP 0.175 VP actinometer: [VP] = 0.1003 M. [CaBz] = 0.00700 M. (AP/CaBz)A =0.574. [AP] = 0.00438 M, lo = 0.0133. 178 Table 58. Quenching of m-Methylbenzophenone Formation upon Irradiation of m-Chloromethylbenzophenone. HPLC analysis: Microsorb-Si Kq1: = 312 Hexane / ethyl acetate (97 :3 ) 1.0 ml / min, @ 270nm Sample [Naphethalene] ( m-MeAP/MeBz)A <00/<0 #1 0 0.266 1 .0 #2 0.00359 0.124 2.15 #3 0.00453 0.107 2.49 #4 0.00640 0.0899 2.96 #5 0.00952 0.0625 4.25 #6 0.01077 0.0574 4.64 #7 0.01420 0.0509 5.22 [m-CICH2BP] = 0.01114 M, [MeBz] = 0.01105 M, [HSPh] = 0.0546 M, 4 hours, 366 nm 179 Table 59. Quantum yields of Irradiation of m-(Phenylthio)methyl- acetophenone HPLC analysis: Microsorb-Si Hexane / ethyl acetate ( 95 : 5) 1.0 ml / min, @ 270nm Compound (Compound / MeBz)A Concentration <0 m-PhSCH2AP 4.684 0.008088 0.36 m-MeAP 0.136 0.00175 0.32 [ m-PhSCH2AP] = 0.01004 M, [M682] 8 0.00954M, [HSPh] = 0.0555 M, 3 hours. 313 nm. RF: MeBz/m-PhSCH2AP 0.181; MeBz/m-MeAP 1.35. VP actinometer: [VP] = 0.1003 M. [CeBz] = 0.00700 M. (AP/0382M = 0.235. [AP] = 0.00179 M, 1o = 0.00543 ein 1-1. 180 Table 60. Quenching of m-Methylacetophenone Formation upon Irradiation of m-Phenylthiomethylacetophenone. HPLC analysis: Microsorb-Si Kq1: = 1.88 Hexane / ethyl acetate ( 98 : 2 ) 1.0 ml / min, @ 270nm Sample [Naphethalene] ( m-MeAP/MeBz)A <00/<0 #1 0 0.1 14 1 .0 #2 0.1278 0.0896 1 .272 #3 0.3396 0.0689 1 .655 #4 0.4577 0.0619 1 .840 #5 0.5960 0.0529 2.1 54 #6 0.7441 0.0474 2.405 [m-PhSCH2AP] = 0.01079 M, [MeBz] = 0.00931 M, [HSPh] = 0.0487 M, 6 hours, 366 nm 181 Table 61. Quantum yield of Irradiation of o-Benzoyl-N,N-dibenzylaniline Hydrochloride in acetonitrile. Compound (Compound / Std)A [Compound] <0 Bz2NBPzHCla 7.397 0.01724 M 0.0145 BzPh2-indole° 1.640 0.0006146 M 0.0067 a[BzNBP:HCI] =0.0198 M, [std] = [01082] = 0.1644 M, VP actinometry: [VP] = 0.09960 M, [C16] = 0.006695 M, [AP] = 0.03344 M. Irradiation: 366nm, 27 hours b[BzNBP:HCl] =0.01967 M, [std] = [01082] = 0.07528 M, VP actinometry: [VP] :- 0.1010 M, [C16] = 0.006924 M, [AP] = 0.0234 M. Irradiation: 366nm, 24 hours Table 62. Effct of Water on Quantum Yield of Irradiation of o-Benzoyl-N,N-dibenzylaniline Hydrochloride H20(%) A(B22NBP:HCI / Std)A c (BzPh2-indole IStd)A c 0 1.17 0.0145 1.12 0.0067 2 0.90 0.0112 0.55 0.0033 4 0.37 0.0046 0.49 0.0029 6 0.06 0.00099 0.29 0.0017 6 0.08 0.00099 0.15 0.00090 1 0 0.098 0.00059 [BzNBPzHCI] =0.02078 M, [std] = [C1oBz] = 0.009933 M, 366nm, 24 hours, in acetonitrile. 182 Table 63. Quenching of N-Benzyl-2,3-diphenylindole Formation upon Irradiation of o-Benzoyl-N,N-dibenzylaniline Hydrochloride.° flELanalxsjs: Reverse phase column CH30H/H20 (95 / 5) kq‘t = 2.44 Rate: 1.0 ml/min. @ 270nm Sample [Ethyl Sorbate] ( BzPh2-indole / C1 oBz)A <00/<0 #1 0 0.8175 1.0 #2 0.2123 0.5471 1 .494 #3 0.3972 0.41 17 1 .986 #4 0.5931 0.3296 2.480 #5 0.8059 0.2806 2.914 #6 1.0154 0.2344 3.488 acetonitrile. a[BzzNBPzHCI] =0.0198 M, [std] = [C1oBz] = 0.1644 M, 366nm, 27 hours, in 183 Table 64. Quenching of N-Benzyl-2,3-diphenylindole Formation upon Irradiation of o-BenzoyI-N,N-dibenzylaniline Hydrochloride in 8% Aqueous Acetonitrile Solution. W: Reverse phase column kq'c = 219.8 CH3OH/H20 (95/5) Rate: 1.0 ml/min. @ 270nm Sample [Sodium Sorbate] I( Bzth-indole / C1 082) A (how #1 0 0.3379 1 .0 #2 0.0007457 0.2933 1 .1 52 #3 0.002088 0.2145 1 .575 #4 0.002833 0.2033 1 .662 #5 0.004325 0.1737 1 .946 #6 0.005220 0.1565 2.1 58 [BzzNBPzHCI] =0.008353 M,[std] = [C1oBz] = 0.004921 M, Irradiation: 366 nm, 48 hours 184 Table 65. Quenching of N-Benzyl-2,3—diphenylindoIe Formation upon Irradiation of o-Benzoyl-N,N-dibenzylaniline Hydrochloride in 4% Aqueous Acetonitrile Solution with Sodium Sobate. HPLC analysis: Reverse phase column kq'c = 347.0 CH30H / H20 (95/5) Rate: 1.0 mein. @ 270nm Sample [Sodium Sorbate] |( Bzth-indole / C1oBz)A (Do/(b #1 0 0.858 1.0 #2 0.000895 0.753 1 .1 4 #3 0.00209 0.548 1 .57 #4 0.00313 0.411 2.09 #5 0.00403 0.375 2.29 #6 0.00537 0.300 2.86 [BzzNBPzHCI] =0.007834 M,[std] = [C1082] = 0.005305 M, Irradiation: 365nm, 36 hours 185 Table 66. Quenching of N-BenzyI-2,3-diphenylindoie Formation upon Irradiation of o-BenzoyI-N,N-dibenzylaniline hydrochloride in 8% Aqueous Acetonitrile Solution with Ethyl Sobate. W: Reverse phase column CH30H/H20 (95/5) Rate: 1.0 ml/min. @ 270nm Sample [Ethyl Sobate] ( Bzth-indole / C1 oBz)A tho/(b #1 0 1 .080 1 .0 #2 0.05792 0.982 1 .099 #3 0.1187 0.950 1.137 #4 0.1783 0.775 1 .395 #5 0.2558 0.402 2.684 #6 0.3089 0.357 3.030 #7 0.3519 0.349 3.098 [BzzNBPzHCI] =0.007337 M,[std] = [C1082] = 0.005177 M, Irradiation: 366 nm, 36 hours 186 Table 67. Quenching of N-Benzyl-2,3-diphenylindole Formation upon Irradiation of o-Benzoyl-N,N-dibenzylaniline Hydrochloride in 8% Aqueous Acetonitrile Solution. W: Reverse phase column CH30H/H20 (95/5) Rate: 1.0 ml/min. @ 270nm Sample [Quencher] b ( Bzth-indole / C1oBz)A coo/o #1 0 0.397 1.0 #2 0.000867 0.436 0.91 1 #3 0.00318 -- --- #4 0.01 14 0.496 0.800 #5 0.0239 0.503 0.789 #6 0.0509 0.438 0.906 [BzzNBPzHCI] =0.007530 M,[std] = [C1082] = 0.004930 M, Irradiation: 366 nm, 48 hours. b1-naphethylethylamine hydrochloride 187 Table 68. Stern-voimer Analysis of o-Benzoyltrimethylanilinium tetrafluroborate in CH3CN <0 = 0.56 mm: @340 nm kqt = 86 Sample [Et Sorbate] M340 ¢OI