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1/98 CDMpOS-nu

 

 

INT RAMOLECULAR TRIPLET ENERGY TRANSFER IN FLEXIBLE MOLECULES

by

Petr Klan

A DISSERTATION

Submitted to
Michigan State University
In partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department of Chemistry
1 998

ABSTRACT

INTRAMOLECULAR TRIPLET ENERGY TRANSFER IN FLEXIBLE MOLECULES
by
Petr Klan

Intramolecular triplet energy transfer rate constants in various flexible
bichromophoric systems D-(CH2)x-O-A (D = benzoyl, 4-methylbenzoyl; A = 2-naphthyl,
4-, 3-, 2-biphenyl; x = 3-14) have been determined by steady-state quenching and
quantum yield measurements. The magnitude of the rate constants in 4-atom tether
molecules is comparable to those with a rigid spacer between chromophores, so that a
through-bond mechanism is presumed. As the tether becomes longer, through-space
interaction dominates and is, in long molecules, the only mechanism responsible for
transfer. Rates in long molecules were found remarkably high - lower only by one order
of magnitude than in those with 4-atom tethers. It is explained by the existence of a small
fraction of conformers having both chromophores in close proximity. Energy transfer in
all systems reported here was exothermic. 2-Naphthyl acceptor was replaced by a
biphenyl group and the transfer rate constants were found to be lower by a factor of
approximately two, which is in agreement with earlier bimolecular measurements. When
4-methylbenzoyl group having 1t,1t* excited state was used instead of n,1t* excited
benzoyl, the rate increase was small but consistent for all tether lengths. An unexpected
sudden increase in rate for medium chain-length molecules is explained by a larger
number of favorable conformers and further in biphenyl derivatives by a rotation along

the terminal O-C bond between the tether and the aromatic ring. As was expected,

inclusion of one oxygen atom in the polymethylene chain for polyethyleneoxide caused

better flexibility and so higher transfer rates.

To Jana,
Katerina,
and Barbara

iv

 

ACKNOWLEDGMENTS

I am grateful to Dr. Peter J. Wagner for opening the door to the magical world of
photochemistry for me. I wish to thank him for his guidance, support, and especially the
freedom to work and explore science in his laboratory.

I am grateful to the National Science Foundation and Michigan State University
for financial support in the form of research and teaching assistantships. I would like to
thank the Chemistry Department and the Biochemistry Department for the use of their
faucilitieas.

It was pleasure to work with all my friends in the Wagner research group. I thank
them for their help, encouragement, and entertaining discussions. I wish to thank to Dr.
Ali Zand for comments on the thesis.

I am indebted to my wife Jana and my daughters Katerina and Barbara who came
across the ocean to support me in my study and work. I thank them for their love and

pafience.

TABLE OF CONTENTS

LIST OF FIGURES ................................................................................................ viii

LIST OF TABLES ..................................................................................................... x
LIST OF SCHEMES ............................................................................................ xviii
LIST OF ABBREVIATIONS ................................................................................ xix
1. INTRODUCTION .............................................................................................. 1
1.1 Objectives ........................................................................................................ 1
1.2 Energy Transfer: Basic Principles ................................................................... 2
1.3 Bimolecular Energy Transfer .......................................................................... 4
1.3.1 Bimolecular Energy Transfer: Thermodynamic and Steric Effects .......... 4
1.3.2 Bimolecular Energy Transfer: Electronic Effects ..................................... 7

1.4 Intramolecular Processes ................................................................................ 9
1.4.1 Rigid Molecules: Through-bond Interaction ............................................ 9
1.4.2 Flexible Molecules: Through-space Interaction ........................................ 14

1.5 Cyclization and Conformation of Flexible Molecules .................................... 24
1.6 Monitoring System: Calculation of the Transfer Rate Constants .................... 32
1.7 Goals of Research ............................................................................................ 36
2. RESULTS ............................................................................................................ 38
2.1 General Information ......................................................................................... 38
2.1.1 Bichromophores ......................................................................................... 38
2.1.2 Synthesis of Bichromophores .................................................................... 39

2.2 Stem-Volmer and Quantum Yield Measurements .......................................... 41
2.3 Calculations ..................................................................................................... 45
3. DISCUSSION ...................................................................................................... 47
3.1 Thermodynamics ............................................................................................. 47
3.2 Energy Transfer Rate Constants ...................................................................... 49
3.3 Flexibility of the Tether .................................................................................. 54
3.4 Electronic Factors ........................................................................................... 60
3.5 Isomeric Differences ....................................................................................... 63
3.6 Summary ......................................................................................................... 71
4. EXPERIMENTAL ........................................................................................ 72
4.1 Instrumentation ................................................................................................ 72
4.2 Preparation of Bichromophores ....................................................................... 73
4.2.1 Synthesis of (o-Aryloxyalkyl Aryl Ketones ................................................ 73
4.2.2 Synthesis of 4-(2-Aryloxyethyloxy)-l-phenylbutan-l-ones ...................... 116

vi

4.2.3 Synthesis of Arylethyl Ethers .................................................................... 121

4.3 Ultraviolet and Phosphorescence Spectroscopy .............................................. 122
4.4 Photochemical Procedures and Experiments .................................................. 128
4.4.1 Purification of Solvents ............................................................................. 128
4.4.2 Purification of Standards, Internal Standard, Actinometer, and Quencher 129
4.4.3 Glassware .................................................................................................. 130
4.4.4 Sample Preparation, Degassing, and Irradiation Procedures .................... 130
4.4.5 Quenching Studies .................................................................................... 131
4.4.6 Photoproduct Identification ...................................................................... 132
4.4.7 Analysis of Photoproducts ........................................................................ 133
4.4.8 Bimolecular Quenching ............................................................................ 135
4.4.9 Quantum Yields Measurements ................................................................ 187
5. REFERENCES .............................................................................................. 214

vii

LIST OF FIGURES

Figure 1. Frontier orbital representation of electron exchange in triplet energy transfer... 3

Figure 2. Ouroboros from the book Chrysopoeia by an early alchemist Cleopatra during
the Alexandrian Period in Egypt. ................................................................................ 4

Figure 3. Two types of exciplexes: n-type and 1t-type. ...................................................... 8

Figure 4. Possible interactions for n,1t* acetone donor with acceptors possessing low
lying n,1t* and 1t,1t* states: the first step of the electron exchange. ............................. 8

Figure 5. Plot of the rate constants of the all-equatorial (cc) and equatorial-axial (ea)
compounds 9 - 12 against the number of o—bonds separating donor and acceptor .. 12

Figure 6. Dependence of the frequency for intramolecular electron exchange on the
number of atoms separating the phthalimide groups by a methylene chain, in HMPA.
................................................................................................................................... 18

Figure 7. End-to-end cyclization probability W(O) of the molecules 23 as a function of
chain length. Curves labeled syn and anti describe the particular conformations of
the ester group in 23. ................................................................................................. 29

Figure 8. Distribution of the end—to-end distance r of l-naphthalene-(CH2)n-1-

naphthalene. The numbers in the figure represents the number of CH2 groups n in the
molecule. ................................................................................................................... 30

Figure 9. Unnonnalized histogram of end-to-end distance for n-alkane chains from the
Monte Carlo program. A total of 5x105 samples were taken for each of the three
chain lengths: (A) 8 carbon atoms, (B) 12 carbon atoms, (C) 18 carbon atoms. ..... 31

Figure 10. AM] minimized structure of Bz-3-O-2Np showing the distance between the

carbonyl oxygen and the closest carbon of the naphthyl group. ................................ 45
Figure 11. AM] minimized structure of Bz-7-O-2Np showing the distance between the
carbonyl oxygen and the closest carbon of the naphthyl group. ................................ 46
Figure 12. Rate constants for triplet energy transfer as a function of the number of atoms
connecting donor and acceptor. .................................................................. . .............. 56
Figure 13. Five characteristic conformations of D—9-OA: the simplified model. ............ 59
Figure 14. Rate constants for triplet energy transfer, km, and for electron transfer, P, as a
function of the number of atoms connecting the donor and the acceptor. ................ 60
Figure 15. An example of the difference between n—1t and 1t-1t interactions. ................... 63

viii

Figure 16. Rate constants for triplet energy transfer, kET, as a function of the number of
atoms connecting the donor and the acceptor ............................................................ 65

Figure 17. Rotation along the O-C terminal bond showing a “reactive volume”: Bz-6-
O4Bp (F), Bz-6-0Np (G), and Bz-6-OZBp (H). ....................................................... 68

Figure 18. Representative example of the minimized geometry by MM2 calculation and
the formal structure of Bz-6-O4Bp ........................................................................... 69

Figure 19. Representative example of the minimized geometry by MM2 calculation and
the formal structure of Bz-6-02Bp ........................................................................... 70

Figure 20. Phosphorescence emission spectra of acetophenone (AP), 4—
methylacetophenone (MeAP), 2-ethoxynaphthalene (2EtONp), 4-ethoxybiphenyl
(4EtOBp), 3-ethoxybiphenyl (3EtOBp), and 2-ethoxybiphenyl (2EtOBp)
chromophores in 2-methyltetrahydrofuran at 77K. ................................................. 127

ix

LIST OF TABLES

Table 1. Photokinetics of Model (b-Phenoxy Ketones in Cyclohexane ........................... 42
Table 2. Photokinetics of Naphthyloxy Ketones in Cyclohexane .................................... 43
Table 3. Photokinetics of Biphenyloxy Ketones with in Cyclohexane ............................ 44
Table 4. Triplet levels ET of the donor and the acceptor chromophores .......................... 48

Table 5. Intramolecular Energy Transfer Rates in Naphthyloxy Bichromophores
Obtained from Stem-Volmer and Quantum Yield Measurements. ........................... 50

Table 6. Intramolecular Energy Transfer Rates in Biphenyloxy Ketones Obtained from

Stem-Volmer and Quantum Yield Measurements. ................................................... 51
Table 7. Molar Absorptivities of Bz-n-OPh, MeBz-n-OPh, and Bz-3-O-2-OPh ........... 123
Table 8. Molar Absorptivities of Bz-n-O4Bp, Bz-n-O3Bp, and Bz-n-OZBp ................ 124
Table 9. Molar Absorptivities of Bz-n-ONp .................................................................. 125
Table 10. Molar Absorptivities of MeBz-n-ONp, MeBz-n-O4Bp, Bz-3-O-2-O4Bp, and

actinometers ............................................................................................................. 125
Table 11. Phosphorescence Emission Data .................................................................... 126
Table 12. Calibration constants ...................................................................................... 134
Table 13. HPLC Condition Sets. .................................................................................... 134

Table 14. Stem-Volmer Quenching of the Acetophenone Formation in Bz-3-OPh with
2,5—Dimethy1-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 136

Table 15. Stem-Volmer Quenching of the Acetophenone Formation in Bz-4-OPh with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 137

Table 16. Stem-Volmer Quenching of the Acetophenone Formation in Bz-S-OPh with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 138

Table 17. Stem-Volmer Quenching of the Acetophenone Formation in Bz-7-OPh with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 139

Table 18. Stem-Volmer Quenching of the Acetophenone Formation in Bz- 10-0Ph with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 140

Table 19. Stem-Volmer Quenching of the Acetophenone Formation in 82-1 l-OPh with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 141

Table 20. Stem-Volmer Quenching of the Acetophenone Formation in Bz-3-O-2-0Ph
with 2,5-Dimethy1-2,4-hexadiene at 366 nm in Cyclohexane. ................................ 142

Table 21. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in MeBz-3-
OPh with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane ......................... 143

Table 22. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in MeBz-4-
OPh with 2,5-Dimethyl-2,4—hexadiene at 366 nm in Cyclohexane ......................... 144

Table 23. Stern-Volmer Quenching of the 4-Methylacetophenone Formation in MeBz-S-
OPh with 2,5-Dimethyl—2,4—hexadiene at 366 nm in Cyclohexane ......................... 145

Table 24. Stem-Volmer Quenching of the Acetophenone Formation in Bz-3-ONp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane ......................................... 146

Table 25. Stem-Volmer Quenching of the Acetophenone Formation in Bz-4-ONp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 147

Table 26. Stem-Volmer Quenching of the Acetophenone Formation in Bz-S-ONp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 148

Table 27. Stern-Volmer Quenching of the Acetophenone Formation in Bz-6-ONp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 149

Table 28. Stem-Volmer Quenching of the Acetophenone Formation in Bz-7-ONp with
2,5-Dimethy1-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 150

Table 29. Stern-Volmer Quenching of the Acetophenone Formation in Bz-9-0Np with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 151

Table 30. Stem-Volmer Quenching of the Acetophenone Formation in Bz- IO—ONp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 152

Table 31. Stem-Volmer Quenching of the Acetophenone Formation in Bz-l l-ONp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 153

Table 32. Stem-Volmer Quenching of the Acetophenone Formation in Bz-14-ONp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 154

Table 33. Stem-Volmer Quenching of the Acetophenone Formation in Bz-3-O4Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 155

Table 34. Stem-Volmer Quenching of the Acetophenone Formation in Bz-4-O4Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 156

Table 35. Stem-Volmer Quenching of the Acetophenone Formation in Bz-5-04Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 157

Table 36. Stem-Volmer Quenching of the Acetophenone Formation in Bz-6-O48p with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 158

Table 37. Stern-Volmer Quenching of the Acetophenone Formation in Bz-7-O4Bp with
2,5-Dimethyl-2,4—hexadiene at 366 nm in Cyclohexane. ........................................ 159

Table 38. Stem-Volmer Quenching of the Acetophenone Formation in Bz—9-O4Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 160

Table 39. Stem-Volmer Quenching of the Acetophenone Formation in Bz-lO-O4Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 161

Table 40. Stem-Volmer Quenching of the Acetophenone Formation in Bz-l l-O4Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 162

Table 41. Stern-Volmer Quenching of the Acetophenone Formation in Bz-l4-O4Bp with
2,5-Dimethy1-2,4-hexadiene at 366 nm in Benzene. ............................................... 163

Table 42. Stem-Volmer Quenching of the Acetophenone Formation in Bz-3-O2Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 164

Table 43. Stem-Volmer Quenching of the Acetophenone Formation in Bz—4-02Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 165

Table 44. Stern-Volmer Quenching of the Acetophenone Formation in Bz-5-02Bp with
2,5-Dimethyl-2,4—hexadiene at 366 nm in Cyclohexane. ........................................ 166

Table 45. Stern-Volmer Quenching of the Acetophenone Formation in Bz-6-OZBp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 167

Table 46. Stem-Volmer Quenching of the Acetophenone Formation in Bz-7-OZBp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 168

Table 47. Stem-Volmer Quenching of the Acetophenone Formation in Bz-9-OZBp with
2,5-Dimethy1-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 169

Table 48. Stern-Volmer Quenching of the Acetophenone Formation in Bz-lO—O2Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 170

Table 49. Stern-Volmer Quenching of the Acetophenone Formation in Bz-l 1-02Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 171

Table 50. Stem-Volmer Quenching of the Acetophenone Formation in Bz-14-02Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 172

xii

Table 51. Stem-Volmer Quenching of the Acetophenone Formation in Bz-3-O3Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 173

Table 52. Stern-Volmer Quenching of the Acetophenone Formation in Bz-6-O3Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 174

Table 53. Stem-Volmer Quenching of the Acetophenone Formation in Bz—7-O3Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 175

Table 54. Stem-Volmer Quenching of the Acetophenone Formation in Bz-9-03Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 176

Table 55. Stem-Volmer Quenching of the Acetophenone Formation in Bz—lO-O3Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 177

Table 56. Stern-Volmer Quenching of the Acetophenone Formation in Bz-14-O3Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ........................................ 178

Table 57. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in MeBz-3-
ONp with 2,5-Dimethy1-2,4-hexadiene at 366 nm in Cyclohexane ........................ 179

Table 58. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in MeBz—4-
ONp with 2,5-Dimethyl-2,4—hexadiene at 366 nm in Cyclohexane ........................ 180

Table 59. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in MeBz—S-
ONp with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane ........................ 181

Table 60. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in MeBz-6-
ONp with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane ........................ 182

Table 61. Stem-Volmer Quenching of the 4-Methy1acetophenone Formation in MeBz-7-
ONp with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane ........................ 183

Table 62. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in MeBz-
ll-ONp with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane ................... 184

Table 63. Stem-Volmer Quenching of the 4—Methylacetophenone Formation in MeBz-3-
O4Bp with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane ...................... 185

Table 64. Stem-Volmer Quenching of the Acetophenone Formation in Bz-3-O-2-O4Bp
with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane. ................................ 186

Table 65. Quantum Yields of the Acetophenone Formation in Bz-3-OPh with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 188

Table 66. Quantum Yields of the Acetophenone Formation in Bz-4—OPh with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 188

xiii

Table 67. Quantum Yields of the Acetophenone Formation in Bz-S-OPh with
Valerophenone as an Actinometer at 366 nm in Cyclohexane. ............................... 189

Table 68. Quantum Yields of the Acetophenone Formation in Bz-7-OPh with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 189

Table 69. Quantum Yields of the Acetophenone Formation in Bz—lO-OPh with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 190

Table 70. Quantum Yields of the Acetophenone Formation in Bz-l 1-OPh with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 190

Table 71. Quantum Yields of the Acetophenone Formation in Bz-3-O-2-0Ph with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 191

Table 72. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-3-OPh with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 191

Table 73. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-4-OPh with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 192

Table 74. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-S-OPh with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 192

Table 75. Quantum Yields of the Acetophenone Formation in Bz-3-ONp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 193

Table 76. Quantum Yields of the Acetophenone Formation in Bz-4-ONp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 193

Table 77. Quantum Yields of the Acetophenone Formation in Bz-S-ONp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane. ............................... 194

Table 78. Quantum Yields of the Acetophenone Formation in Bz-6-ONp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane. ............................... 194

Table 79. Quantum Yields of the Acetophenone Formation in Bz-7-0Np with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 195

Table 80. Quantum Yields of the Acetophenone Formation in Bz—9-ONp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane. ............................... 195

Table 81. Quantum Yields of the Acetophenone Formation in Bz-lO-ONp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 196

Table 82. Quantum Yields of the Acetophenone Formation in Bz-l l-ONp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 196

xiv

Table 83. Quantum Yields of the Acetophenone Formation in Bz- l4-ONp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 197

Table 84. Quantum Yields of the Acetophenone Formation in Bz-3-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 197

Table 85. Quantum Yields of the Acetophenone Formation in Bz-4-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 198

Table 86. Quantum Yields of the Acetophenone Formation in Bz-S-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 198

Table 87. Quantum Yields of the Acetophenone Formation in Bz—6-O43p with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 199

Table 88. Quantum Yields of the Acetophenone Formation in Bz-7-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 199

Table 89. Quantum Yields of the Acetophenone Formation in Bz-9-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 200

Table 90. Quantum Yields of the Acetophenone Formation in Bz-lO-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 200

Table 91. Quantum Yields of the Acetophenone Formation in Bz-l 1-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 201

Table 92. Quantum Yields of the Acetophenone Formation in Bz-14-O43p with
Valerophenone as an Actinometer at 366 nm in Benzene. ...................................... 201

Table 93. Quantum Yields of the Acetophenone Formation in Bz-3-OZBp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 202

Table 94. Quantum Yields of the Acetophenone Formation in Bz—4-O2Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 202

Table 95. Quantum Yields of the Acetophenone Formation in Bz-S-OZBp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 203

Table 96. Quantum Yields of the Acetophenone Formation in Bz-6-O2Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 203

Table 97. Quantum Yields of the Acetophenone Formation in Bz-7-OZBp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 204

Table 98. Quantum Yields of the Acetophenone Formation in Bz—9-02Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 204

XV

Table 99. Quantum Yields of the Acetophenone Formation in Bz-lO-O2Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane. ............................... 205

Table 100. Quantum Yields of the Acetophenone Formation in Bz—l 1-O2Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 205

Table 101. Quantum Yields of the Acetophenone Formation in Bz-l4-O2Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 206

Table 102. Quantum Yields of the Acetophenone Formation in Bz-3-O3Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane. ............................... 206

Table 103. Quantum Yields of the Acetophenone Formation in Bz-6-O3Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane. ............................... 207

Table 104. Quantum Yields of the Acetophenone Formation in Bz-7-O3Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 207

Table 105. Quantum Yields of the Acetophenone Formation in Bz-9-O3Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane. ............................... 208

Table 106. Quantum Yields of the Acetophenone Formation in Bz-lO-O3Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane. ............................... 208

Table 107. Quantum Yields of the Acetophenone Formation in Bz-14-O3Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 209

Table 108. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-3-ONp
with Valerophenone as an Actinometer at 366 nm in Cyclohexane ........................ 209

Table 109. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-4-ONp
with Valerophenone as an Actinometer at 366 nm in Cyclohexane ........................ 210

Table 110. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-S-ONp
with Valerophenone as an Actinometer at 366 nm in Cyclohexane ........................ 210

Table 111. Quantum Yields of the 4—Methylacetophenone Formation in MeBz-6-ONp
with Valerophenone as an Actinometer at 366 nm in Cyclohexane ........................ 21 1

Table 112. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-7-0Np
with Valerophenone as an Actinometer at 366 nm in Cyclohexane ........................ 21 1

Table 113. Quantum Yields of the 4-Methylacetophenone Formation in MeBz~1 l-ONp
with Valerophenone as an Actinometer at 366 nm in Cyclohexane ........................ 212

Table 114. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-3-O4Bp
with Valerophenone as an Actinometer at 366 nm in Cyclohexane ........................ 212

xvi

Table 115. Quantum Yields of the Acetophenone Formation in Bz-3-0-2-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane ................................ 213

xvii

LIST OF SCHEMES

Scheme 1. .......................................................................................................................... 7
Scheme 2. Norrish Type 11 Reaction ................................................................................ 14
Scheme 3. ........................................................................................................................ 21
Scheme 4. ........................................................................................................................ 23
Scheme 5. ........................................................................................................................ 25
Scheme 6. ........................................................................................................................ 26
Scheme 7. Photokinetics of a Bichromophoric System ................................................... 34
Scheme 8. ........................................................................................................................ 38
Scheme 9. ........................................................................................................................ 39
Scheme 10. ...................................................................................................................... 47
Scheme 11. Synthesis of (o-Iodoalkyl Aryl Ketones ........................................................ 73
Scheme 12. Synthesis of (o-Aryloxyalkanoaryl Ketones (R = H, Me) ............................. 76
Scheme 13. Synthesis of (o-Iodoalkanoaryl Ketones (R = H, Me) ................................... 95
Scheme 14. Synthesis of (o-Aryloxyalkanophenyl Ketones ........................................... 107
Scheme 15. Synthesis of 4-(2-Aryloxyethyloxy)-1~phenylbutan-1-ones ....................... 117

xviii

ITET

ISC

MO

SOC

RIS

LIST OF ABBREVIATIONS

Intramolecular triplet energy transfer
Intersystem crossing

Molecular orbital

Spin orbit coupling

Rotational isomeric state

xix

1. INTRODUCTION

1.1 Objectives

The subject of this dissertation is the intramolecular triplet energy transfer (IT ET)
between two chromophores connected by a flexible tether. In this project, I chose to
study how interchromophore distance, character of chromophores, and changes in the
tether affect energy transfer rate constants. It was achieved by systematically increasing
the length of the polymethylene tether, altering the electronic nature and structure of the
chromophores, and changing the structure of the tether. The energy transfer rate
constants were obtained in photokinetic measurements in which the chemical yields of
photocleavage products were monitored. In our bichromophoric systems, the
photocleavage reaction competes with intramolecular energy transfer and this fact was
used in the rate constant calculations; the cleavage reaction serving as a “system clock”.

Intramolecular triplet energy transfer was studied on some rigid or flexible
systems in the past but there was no systematic work on flexible bichromophores. Such
research, however, started in our research group and I wished to build upon the results of
my predecessors. Photochemistry has proved to be an excellent research tool for this
study. Experiments were not very difficult to accomplish; the Stem-Volmer quenching
technique used for lifetime measurements is well-known for its reliability; and the new
results could be compared with those obtained in previously reported experiments.

Energy transfer is a universal process in nature and its understanding certainly

represents required fundamental knowledge. Our research might help to understand it

better. The introduction chapter contains information on what was known about triplet
energy transfer previously and describes the monitoring system used for energy transfer

rate constant calculations.

1.2 Energy Transfer: Basic Principles

Intramolecular triplet energy transfer is a specific example of energy transfer. It is
necessary to define the type of interaction involved and to show general principles.

Electronically excited molecules may react chemically with other molecules in
their vicinity or they may transfer energy to them. If an excited donor D*, either singlet
or triplet, transfers electronic energy to an acceptor molecule A with the simultaneous
return to its ground state, the process is referred to as electronic energy transferl :

D* + A —> D + A*

Energy transfer can occur either by a radiative, through absorption of the emitted
radiation or by a nonradiative pathway. There are two well established, different
mechanisms for nonradiative energy transfer: the Coulomb and the exchange
mechanism.1

It is generally accepted that energy transfer from an excited triplet to the ground
state of another moiety proceeds via exchange or Dexter mechanism.2'3 The energy

transfer rate constant may be written as
km (exchange) ~ e'ZRDA/ LJ (Equation 1)

where RDA is the distance between the donor and the acceptor, L is a constant related to

an effective average orbital radius of the donor and the acceptor, and J is the spectral

overlap. Exchange mechanism requires an overlap of the orbitals - the partners being in a
close proximity. As depicted in Figure 1, energy transfer by exchange mechanism can be
symbolized as a double electron transfer involving both the HOMO’s and LUMO’s of
the donor and the acceptor. For efficient triplet energy transfer the donor must absorb
substantially the incident light, its intersystem crossing efficiency must be high, and its

triplet energy must be higher than that of the acceptor.4

~15 —l—
—1— +

—H— —1l—
V
D* A D A*

Figure 1. Frontier orbital representation of electron exchange in triplet energy transfer.4

If the donor and the acceptor are parts of the same molecule, the electron
exchange process is called intramolecular energy transfer, which can occur by either a
through-bond or a through-space mechanism, or by a combination of both. In systems
where the through-bond mechanism was observed, chromophores were separated only by
several bonds from each other.5 On the other hand, close proximity of both
chromophores, when molecular structure allows, is necessary for a through-space
mechanism.

Energy transfer in a molecule with the donor and the acceptor connected by a
flexible tether has a nice parallel in an old Greek, Gnostic, and medieval symbol

Ouroboros (Figure 2). The serpent biting its own tail, that had several meanings in many

ancient cultures, brought a mystical heritage into medieval alchemy6 as well as into

modern photochemistry.7

 

Figure 2. Ouroboros from the book Chrysopoeia by an early alchemist Cleopatra during
the Alexandrian Period in Egypt.8

1.3 Bimolecular Energy Transfer
There are many similarities between bimolecular and intramolecular energy

transfer. The bimolecular interaction was studied extensively in the past and many

findings are relevant to our intramolecular studies.

1.3.1 Bimolecular Energy Transfer: Thermodynamic and Steric Effects

According to Equation 1, triplet energy transfer by the exchange mechanism is a
short-range phenomenon and the rate constant decreases exponentially with the donor -
acceptor separation RDA. Since it requires a close proximity of both partners, the

exchange mechanism is also called the overlap mechanism. Triplet energy transfer is a

spin-allowed process according to the Wigner-Witmer spin-selection rules, where the
total spin must not change during a reaction.9

The first example of triplet energy transfer was provided by the classic
experiment of Terenin and Ermolaev,10 in which they demonstrated that the
phosphorescence of naphthalene in a rigid solution at 77K could be excited by 366 nm
light. Naphthalene itself did not absorb at this wavelength but benzophenone added to
the solution did and provided energy transfer to naphthalene. A crude model derived
from Dexter’s formula (Equation 1) that describes the distance dependence of energy

transfer by exchange mechanism as a function of distance (Equation 2) was reported.ll
log kET (exchange) = 13 - (2RDA/ 2.3) (Equation 2)

As a result, energy transfer rate kg = 4.5x108 M"s", for example, corresponds to
distance, RDA = 5 A, between chromophores.

Bimolecular as well as intramolecular energy transfer rate constants depend on
overall reaction thermodynamics. When the triplet level of the donor lies about 3 kcal
mol'1 or more higher than that of the acceptor, the bimolecular transfer is exothermic and
nearly diffusion controlled.4 Scaiano, Wagner, and coworkers12 found that bimolecular
energy transfer rate constant between benzoyl donor (ET ~ 72 kcal/mol)13 and 1-
methylnaphtalene acceptor (ET ~ 61 kcal/mol)14 in benzene was 8.4x109 M"s'1. When
both triplet energies are same, kET is smaller by about a factor of 100. Bimolecular rate
constants for self-quenching by ground state ketone were found to be in the 106-108

M'ls'l range.15

Steric effects were shown to be significant in some cases. The introduction of
gem-dimethyl groups into diene used as a quencher reduces the rate constant of

fluorescence quenching of diazabicyclooctene (1).'6

”N
N
On the other hand steric effects in bimolecular triplet energy transfer in
quenching of 0t,a—dimethylvalerophenone (2) by 2,5-dimethyl-2,4-hexadiene and 2-
chloronaphthalene were reported as unimportant, primarily because the interaction
distance between the donor and the acceptor in solution is on order of 4 A, long enough

to preclude large steric effects.'7

0

Scaiano, Wagner, and coworkers12 measured rate constants for quenching of

2

various triplet aryl ketones by conjugated dienes and some aromatics in order to study
steric effects on energy transfer. They found that steric effects that limit closeness of
approach are relatively unimportant in triplet energy transfer, primarily because diffusion
control masks small steric decreases in in-cage energy transfer rates (Scheme 1).
However, large stereoelectronic effects were found when n-system of donor or acceptor
were twisted such that the orbital overlap necessary for electron exchange was

minimized. Arrhenius plots for the ketone quenching by dienes revealed that the

differences in rates involved mainly entropy effects, Ea values were found to be similar

for all chromophore pairs.12

kdiff kET

[D* ..... A]-—> D ..... A*]—>D+A*

 

D*+A

 

k-diff

Scheme 1.

1.3.2 Bimolecular Energy Transfer: Electronic Effects
Electronic effects - delocalization of excitation energy, as well as orientation of

the overlapping orbitals can affect energy transfer.

It has been suggested that as much as 50% of the total spin density in the lowest
triplet state (n,1t‘) of benzophenone resides on the aromatic rings.18 The spin density
distribution on the carbonyl group was found to be highest for the non-bonding orbital on
oxygen.19 In the study of self-quenching deactivation of 4,4’-disubstituted benzophenone
triplets via exciplex formation, a dual reaction pathway was observed.20 It was
concluded that the self-quenching of benzophenones having para electron-donating
subtituent proceeded via exciplex 3 (n-type exciplex) between the half-filled n orbital of
the carbonyl and the 1: system of the aromatic ring. A different exciplex 4 (It-type
exciplex) was facilitated in benzophenones with para electron-withdrawing substituents
between the half-filled 1!?“ system of the donor and the unfilled 1t* system of the acceptor

(Figure 3).

\ CO-Ph-X § 0

3 X 4

X = CH3, CH30, (CH3)2N x =CN, CF3, COOCH3

Figure 3. Two types of exciplexes: n-type and 1t-type.

The quenching of acetone phosphorescence by a series of aryl alkyl ketones

possessing lower triplet energies than acetone was reported.21 The quenching constants

/\
m+ 1r* nan—1,—

.._t_
n—l— —H—« "—1— -H—" n+ —H—“

 

 

 

“11‘

Figure 4. Possible interactions for n,1t* acetone donor with acceptors possessing low
lying n,1t* and 1c,1t* states: the first step of the electron exchange.

were found to be lower for ketones with n,1t* configuration than those with 1t,1t*. That
difference was explained by assuming a different interaction between the partners
(Figure 4). Concerted and stepwise mechanisms of electron exchange were discussed in

terms of different geometries of n - 1t and 1t — 1t orbital overlap. The latter was assumed

to be more efficient because of a parallel geometry, same character of orbitals, and a
lower steric hindrance.
On the other hand, a study of charge transfer in the photoreduction of various

phenyl ketones22 showed the n,1t* and 1t,1t* triplets to be of similar reactivity.

1.4 Intramolecular Energy Transfer

1.4.1 Rigid Molecules: Through-bond Interaction

In molecules where substituents are attached to the ends of a rigid or a very short
tether, through-bond interaction may be the only significant mechanism for any physical
process between them, since the geometry of the molecule prevents their close proximity
through space. Studies of such rigid systems bring a deeper understanding of geometric
and electronic demands for such a process. Molecular rigidity, however, can be

controlled by solvent viscosity and temperature as well.

In 1963, Hammond and coworkers23 reported evidence for intramolecular triplet
energy transfer (ITET) in 4-(l~naphthylmethyl)benzophenone (5). Irradiation of 5 at 366
nm, where only benzophenone absorbs, led to a characteristic phosphorescence emission
of the only naphthyl moiety. This observation suggested that the phosphorescence can
result from IT ET between the chromophores. ITET was believed to proceed at rate of

higher than 109 s'1 with 100% efficiency.

10

5 O

Filipescu and coworkers24 reported an exothermic ITET between nonconjugated
chromophores with fixed orientation. An efficient transfer was found between tetralin-

1,4-dione and fluorene chromophores held together by a rigid spacer (6).

 

Keller25 reported that triplet excitation energy was completely transferred
between anthrone and naphthalene chromophores separated by a spiro linkage in
compounds 7 and 8. The study presented an interesting opportunity to study an influence
of chromophore orientation on ITET. In solutions with 104-10'5 M concentration,
selective excitation of the anthrone chromophore populated excited singlet state which
intersystem crossed to the triplet, underwent exothermic energy transfer and the
naphthalene chromophore produced phosphorescence. The most intriguing aspect of this
work is the occurrence of energy transfer in the perpendicular orientation, which

precludes the orbital overlap needed for transfer. Keller reasoned that only a small

11

deviation from orthogonality would be necessary to achieve energy transfer by dipole-
dipole mechanism. It was discussed that the exchange energy transfer, a probable source

of energy transfer in these systems, might not be very dependent upon orientation of the

chromophores.

O O

o 0
CO 0
O

7 8

Zimmerman and McKelvey26 studied ITET from benzoyl to naphthyl group in a
bichromophoric system with a rigid bicyclo[2.2.2]octane spacer. Their experiments and

findings were very similar to those of Hammond’s.23

Intramolecular energy transfer as well as electron and hole transfer in rigid
systems were studied by Closs and coworkers.27 Their search was aimed at finding
quantitative similarities and differences in these processes.

ITET was studied on compounds in which a 2-naphthyl group is connected via a
rigid spacer with a 4-benzoy1phenyl group, where the spacer was either a cyclohexane 9:
(C-l,3) and 10: (C-l,4), or a decalin ring 11: (D-2,7) and 12: (D-2,6). The triplet energy

transfer rates were measured in benzene at room temperature by flash photolysis exciting

12

the benzophenone chromophore and monitoring the decay of the TI - Tn absorption of
the benzophenone or the buildup of the naphthalene Tl - Tn absorption. ITET decreased
AND AN” Am, AW”
9: C-1,3 10: C-1,4 ll: D-2,7 12: D-2,6
by nearly three orders of magnitude as the interchromophore distance increased in going
from a cyclohexane to a decalin spacer (Figure 5: cc refers to all-equatorial, and ea to
equatorial-axial substituents). It was also shown that triplet energy transfer can be
regarded as a simultaneous two electron transfer and thus triplet energy transfer rates

may be used to obtain information on electronic coupling in electron transfer and hole

transfer.

 

 

 

log km

10 ‘*

9 ~1—

8 ——

7 —l—

6 __
i i i 1‘
4 5 6 7

Number of Bonds

Figure 5. Plot of the rate constants of the all-equatorial (cc) and equatorial-axial (ea)

compounds 9 - 12 against the number of o—bonds separating donor and acceptor; from
ref. 27c.

13

For compounds 9 - 12 with 2—naphthyl and 4-benzoylpheny1 groups in equatorial-
axial position, ITET rates were slower (Figure 5). In line with ab initio MO calculations,
isomers with axial substituents have transfer rates slower than all-equatorial isomers
because the orbital overlap is poor for bonds held almost perpendicular to each other.28
The nature of the electronic coupling in donor/acceptor systems with cyclohexane-type
spacers were investigated using a superexchange pathway method based on ab initio MO
theory with natural bond orbitals.29 It was found that paths involving hops which skip
over bonds make largest contribution to the total coupling. The dominant pathway in
every case is through C-C antibonds. Koga, Sameshima, and Morokuma30 showed how
MO overlap is dependent on the rotation along the bonds between a chromophore and
the cyclohexane or decalin spacers. The dependency was found to be small but real, and
the study also showed that the electronic coupling in triplet energy transfer is

pr0portional to the product of those of electron transfer and hole transfer.

Sigman and Closs studied free energy and structure dependence on ITET.31 A
series of compounds containing 4-benzophenone or 4-acetophenone donors and various
acceptors (9,9-dimethylfluorenyl, 9-spirofluorenyl, 4-biphenyl, 2-naphthyl, and 2-
benzoquinonyl) connected by a 1,4-cyclohexane spacer in equatorial-axial or equatorial-
equatorial position were studied by a nanosecond flash photolysis. The measured ITET
rates showed an inverted parabolic, i.e. Marcus32 , dependence on the free enthalpy of

reaction.

14

1.4.2 Flexible Molecules: Through-space Interaction

As was shown in paragraph 1.4.1, ITET is proportional to the number of bonds
when through-bond mechanism is applied. In through-space mechanism, however, a
close proximity (overlap of orbitals) of both chromophores, allowed by a favorable
geometry of the flexible tether, is necessary. Intramolecular quenching of the excited
chromophore by the unexcited chromophore can significantly change the course of
photochemical reactions. Thus, in addition to luminescence studies, triplet-sensitized cis-

34 .35

trans geometrical isomerization33 and Norrish Type II reaction of excited ketones

were used in monitoring of intramolecular energy transfer.

/
\

OH

(j\)k
ll

(2*

Scheme 2. Norrish Type 11 Reaction

 

Triplet-sensitized cis-trans isomerization is a photochemical interconversion of
cis and trans isomers containing an olefinic link thanks to the biradical character of the
excited double bond. Norrish type II reaction (Scheme 2), a common reaction of aliphatic

or aromatic ketones, is intramolecular hydrogen abstraction from the yposition. In

15

addition to regenerating the reactant, the resulting biradical can cleave to give an olefin
and an enol, or form a cycloalkanol.

Intramolecular energy transfer of both singlet and triplet excitation in compounds
13 (n = 1-3) was reported in some detail by Lamola and coworkers.36 They found by
luminescence studies that singlet excitation transfer from the lowest singlet state of the
naphthalene group to form the lowest n,1t* singlet state of the benzophenone
chromophore occurred with high but not total efficiency. Triplet energy transfer was

believed to proceed at a rate of >109 3‘1 with 100% efficiency.

O
O

13
One of the most significant studies on the effect of interchromophore distance on
ITET was done by Cowan and Baum37 in 1971. By a systematic increasing of the tether
length in the benzoyl-styryl bichromophoric system 14 the energy transfer rate decreased.
Selective excitation of the carbonyl group led to transfer of triplet energy to the styryl
chromophore, resulting in a trans—)cis styryl isomerization. The rate constants for ITET
in benzene solution of 14, evaluated from triplet quenching data, were: 7.2x1010,

1.0x1010, and 3.3x109 5'1 for series n = 2, 3, and 4, respectively.

0 0

14:n=2,3,4

CI

“YT,

16

Ito and coworkers38 studied intramolecular energy transfer in the bichromophoric
compounds 15. The results from steady state quenching experiments indicated that
energy transfer was fastest in the longest derivative (15: n = 3). It was concluded that
energy transfer via the electron exchange is optimal when 15 has a sandwich
conformation. Weak phosphorescence of the bichromophoric system was attributed to
energy transfer from benzophenone to the most sterically hindered
triisopropylbenzophenone group. Thus, it was reported that excitation preferentially
resides at the most sterically hindered chromophore based on an entropy factor.
Relatively small decrease in internal rotation entropy upon electronic excitation of the
hindered group was considered to be more significant factor than ET difference between
chromophores. These findings can be compared to bimolecular studies‘2 in which
entropic effects on kg were found to be more important then Ea values (Paragraph

1.3.1). Their arguments remain, however, unconvincing.

O

O
o 0 0 0

15:n=l,2,3

Energy transfer migration in macromolecular systems is a subject of current
interest, which reflects its role in photodegradation, photostabilization, photocuring, and
photooxidation. Scaiano and Selwyn39 studied properties of polymers and copolymers of

p-methoxyacrylophenone by flash photolysis. Efficient triplet energy transfer migration

17

with a hopping frequency 4.3x10ll s’1 in chloroform at «60°C was calculated. This high
number (the actual in-cage rate constants were found to be (5-10)x10IO 5"),40 however,
may suggest that intermolecular quenching is more efficient than they assumed or energy

hops across the coiled polymer play an important role.

Winnik and coworkers41 have examined end-to-end cyclization in the
intramolecular phosphorescence quenching reaction of (o-alkenyl esters of
benzophenone-4-carboxylic acid (16). Since the corresponding bimolecular quenching
rate constants are 102 to 103 times smaller than kdm, the intramolecular reaction is
preceded by a conformational equilibrium. Chain shorter than 8 atoms between
chromophores cannot achieve conformations where the 1: electrons of the double bond
overlap with the half-filled n orbital on the benzophenone carbonyl oxygen. A sharp
maximum of intramolecular quenching for the lZ-atom-tether derivative and following
decrease is explained by the entropic factors associated with achieving a reactive

configuration; for chains 11 > 8, the activation energy is independent of chain length.

0

I ! C02(CH2)nCH=CH2

16
In the experiments of Shimada and Szwarc, electron exchange frequency values P
were obtained by ESR for the molecules containing either two l-naphthyl or two
phthalimide groups connected to polymethylene chain.42 The dependence of P upon the

number of the atoms between the two phthalimide groups is shown in Figure 6. The

18

authors concluded that the value of P reflect conformational changes of the investigated
chains. Substitution of oxygen for the methylene group in the chain increased P by a

factor of about 3, provided that the number of tether atoms was 8 or higher.

 

 

 

 

6 r r 1 r r r r

 

2 4 6 8 10 12 14 16 18
Number of Atoms in the Tether

Figure 6. Dependence of the frequency for intramolecular electron exchange on the
number of atoms separating the phthalimide groups by a methylene chain, in HMPA at
the temperature indicated. (O) PI-(CH2)n-Pl"; (O) PI-(CHzCH20)mCH2CH2PI' where PI
is the N-phthalimide group. From ref. 42.

Intramolecular fluorescence quenching in 1,0)-bis(dimethy1amino)alkanes was
shown by Halpem and coworkers.43 In this reaction, one of the amino groups absorbed
light and fluoresced with a quantum yield that was diminished by an intramolecular
interaction. Intramolecular fluorescence quenching rate constants showed a minimum
for 8 methylene groups between the substituents with a sudden increase and leveling off
for 12 - 20 methylenes. The authors concluded that the molecular geometry in the

transition state for intramolecular quenching resemble that of a cycloalkane.

l9

Zachariasse44 examined intramolecular excimer formation in the molecules
pyrene-(CH2)n-pyrene. The dependence of excimer to monomer emission intensity ratio
on chain length showed a characteristic maximum for 3, a minimum for 7-8, and a
sudden increase and leveling off for 10-16 atoms between substituents, similar to what

was observed in other examples.

Wagner and Nakahira45 studied steady-state photochemistry of 6-(4’—
methoxyphenyl)—l-phenylhexane-1,6-dione (17). By monitoring Norrish Type H reaction
products from both ends, they found that triplet state lifetimes of both chromophores
were nearly identical. Since the lifetimes of these chromophores, when in separate
molecules, are quite different, they concluded that an energy transfer equilibrium exists
between the lowest triplet states of both chromophores (3n,1t* of the benzoyl group and

31c,1t* of the methoxybenzoyl group).

    

O

17

The photochemistry of three or-benzoyl-m—azidoalkanes PhCO(CH2)nN3 was
studied by quenching experiments and triplet energy transfer rates were determined by

monitoring Norrish Type 11 products.55 Rates 3.7x108, 0.29x108, and <0.03x108 s", for n

20

= 3, 4, and 5, respectively, were found. The authors suggested that almost 50% of the

quenching interaction may involve some process other than energy transfer.

O

0
Ar

18

Wagner and coworkers46 studied the effect of reversible intramolecular energy
transfer on the photochemistry of diketones (18: Ar = Ph, 2-methy1phenyl). Scheme 3
shows an example of photochemical behavior of 18 (n = 4, Ar = Ph). The acetophenone
chromophore has triplet energy ~ 72 kcal/mol while the benzophenone chromophore ~
69 kcal/mol. 18A underwent Norrish Type II photoelimination but its efficiency was
lowered by exothermic energy transfer to 18B. In benzene, 18B was photostable and
slowly transferred energy uphill to 18A. As in other short flexible bichromophoric

systems, through-space ITET competed with through-bond mechanism.

21

Ap-(CH2)4-Bp
18: n = 4, Ar = Ph

kET

 

 

Ap*-(CH2)4—Bp Ap-(CH2)4-Bp*
k -ET

l8A:n=4,Ar=Ph 18B:n=4,Ar=Ph

i Ap = acetophenone
Norrish Type H Bp = benzophenone

Scheme 3.

Irreversible triplet energy transfer was studied on diketones 19 (n = 3-7) in which
extremely rapid enolization of the excited o-methylbenzophenone chromophore
shortened the triplet lifetime such that uphill energy transfer to benzoyl chromophore
could not compete.46 The transfer rate constants dropped from 4-atom tether to 5-atom
tether molecule and then reached a constant value for all longer derivatives. Through-
space energy transfer was assumed to dominate for those longer molecules in which a

certain number of conformations allow a close proximity of the chromophores.

O

O
O (CH2)n'O 0 CH3

Wagner and El-Taliawi‘” published a study of ITET in flexible cinnamyl esters

19

of (o-benzoylcarboxylic acids (20). Irradiation of 20 at 366 nm, where the styrene barely

22

absorbs, produced efficient cis—mans isomerization. They extended the results of Cowan
and Baum37 by increasing the number of atoms between chromophores. It was shown by
a comparison to Closs’ rigid molecules, in which kET values drop 1 order of magnitude
with each additional bond between chromophores,5 that the higher IT ET rate constants in
more flexible, longer molecules are caused by through-space interaction. In the
molecules with a short tether, however, through-bond interaction, similar to the ITET in
rigid systems, was suggested. ITET rate constants for 20 were: 4x109, 2x109, 1x109, and

5x108 5'1 for n = 1, 2, 3, and 4, respectively.

0 O O
e We —
O

20

Qiao48 studied ITET in m—(4-biphenbxy)alkanophenones (21). The molecules
were irradiated at 313 nm in benzene and Norrish Type II photoelimination was
followed. As in the Wagner and El-Taliawi work,47 ITET rate constants dropped

approximately a factor of 2 for each additional bond between chromophores.

O

21 (n = 3-6)

lll

23

A series of spectroscopic measurements on flexible polymethylene biradicals in
liquid solution was reported by Closs, Forbes, and coworkers.49 In order to get
information about the chain-length dependence of the intramolecular exchange
interaction J, time-resolved electron paramagnetic resonance spectroscopy was used. The
cyclic ketones 22 (n = 8-26) were irradiated by a 308 nm laser flash pulses and the triplet
biradicals 23 were formed in the photoinduced Norrish Type I reaction (Scheme 4).
Through-bond contributions were found to dominate for the shortest acyl-alkyl
biradicals, while the through-space (solvent) mechanism was the major contribution to J
in the long-chain molecules. In the short acyl-alkyl biradicals, J decreased distinctly with
every additional atom in the chain andleveled off when the chain became longer (n > 13).
Such dependence, however, was not observed for alkyl-alkyl biradicals (formed as
byproducts in the same photocleavage), where the difference in J for short and long
chains was negligible. Interesting results about how a double bond or a phenyl ring in the
chain could change flexibility, and so the exchange interaction in the alkyl-alkyl

. . 50
biradicals, were also reported.

0 0* O

367‘ _____.. A614 ——~ a? a
(CH2)n 5 (CH2)n-5 (CH2)n 5
22 23

Scheme 4.

24

1.5 Cyclization and Conformation of Flexible Molecules

The concepts of cyclization and chain flexibility have been linked since earliest
days of concern about conformation in chemistry. In this work, intramolecular energy
transfer in flexible molecules is dependent on conformations of the tether. This section
summarize basic information about cyclization dynamics and kinetics in chemistry as
well as in photochemistry.

There are many known examples of chemical reactions or physical processes
occurring between substituents attached at the ends of a flexible chain molecule.5 ' While
the stereochemical demands for ring formation can be much higher than simple

proximity of the reactants in the ends of the flexible chain,52

a physical process such as
Coulomb energy transfer occurs whenever the terminal donor and acceptor approach to
within 6 to 10 A and even over distances of 50 A.53 Many of the factors that influence
the cyclization of hydrocarbon chains can be seen in a comparison of normal alkanes and
appropriate cycloalkanes. This comparison is normally carried out by examining the
internal energies or heats of formation (AEf° or AH?) and entropies of formation (ASP)
of these pairs of compounds and estimating the changes in energy and entropy which

occur upon cyclization.51

Intramolecular reactions can have their bimolecular counterparts. Scheme 5
shows the parallel between diffusion together of two molecules and rotation together of
two functional groups in the same molecule.7 The major difference between them is that

conformational equilibrium constants of intramolecular reaction are much more sensitive

25

to structure than are diffusion constants. Rotation control represents the intramolecular
equivalent of diffusion-controlled reaction and should be expected whenever the reaction
between A and B is known to be diffusion-controlled. In slow reactions, the

intramolecular rate constant is dependent on the conformational equilibrium constant.

bimolecular intramolecular

A+B m
B

 

 

 

 

k-diff kdiff k_rot krot
kr kr' A

l A + B ] ——> product ‘—--

diffusion control rotational control
(kr > k-diff) (kr ’ > k-rot)
kobsd = kdiff kobsd = krot

structural control conformational equilibrium
(k. << ken) (k. ’ << k...)

kobsd = I(diff kr kobsd = Krot kr I

Scheme 5.

It was shown by Wagner that kinetics of photochemical intramolecular processes
are more complex than chemical processes.7 In Scheme 6, where F and U represent

conformations of the molecule, favorable and unfavorable, respectively, for a given

26

intramolecular interaction, three kinetic situations can be described. The star superscript

means an excited state, and kd and kd’ are rate constants of decay.

 

 

 

 

 

 

F -—l-]-V—— F* 4» product
kd
kur kFU kur=* kFU*
U «L U*
kd
Scheme 6.

For relatively slow excited-state reactions, conformational equilibrium is
established: km: and kup are much faster than kr and kd. Thus, the observed rates
include excited-state conformational equilibrium constants: kobs = krkup/ (km:- + kup)
= Xptkr. The quantum yields is expressed as (I) = xpkrl (xpn-k, + xpekd + XU‘kd’)-

For fast reactions and/or slow conformational change, the reaction is limited by
the ground-state population of favorable conformations: kobs = kr for kpue, kup- << k,, kd;
(I) = kar/ (kr + kd). From the two kinetically distinct excited states (F* and U*), only F*
leads to the reaction and the situation is called ground state control.54 Its bimolecular
counterpart is called “static quenching”.

If conformational change and decay are competitive, it is said that rotation-

controlled reaction occurs: kobs (U) = kupu for km“ ~ kd and km: << kr.

Wagner55 pointed out that the actual rate of an intramolecular process, kp, is a
sum over all favorable conformations which allow the reaction. The contribution of each

individual conformation to the total process depends both on the fractional population of

27

that conformer (Xfi) and on the rate of the process associated with that particular
geometry (kpi) (Equation 3) for Xf (total) = l - xu (total), where Xu are all unfavorable
conformations.

kp = ZXfi kpr’ .
I (Equation 3)

In one of the most thorough studies of ring closure, Mandolini and Illuminati
carried out detailed kinetic studies of intramolecular nucleophilic substitution
reactions.56 Arrhenius parameters were obtained for lactone formation from Br(CH2)n-
zCOz'. Activation energy E2, was found to be large for n = 3 and decreased substantially
for n = 4-6, which does not quite follow a pattern of the strain energy of small rings.
Large values of energy Ea were found for 8- and 9-member ring formation. Entropy of
activation AS“ was large for n = 3-6 and then dropped and oscillated with E3 in a
compensatory manner, so that reactions with particularly unfavorable activation energies

had less negative entropies AS”.

Mathematical models play an important role in understanding chain conformation
and chain dynamics. There are many kinds of models which have been applied and they
range from simple models to very realistic models, in which structural aspects of the
polymer are taken explicitly into account.5 1'57 In discrete models, individual polymer
chains are confined to discrete points in space. Average properties associated with the

polymer are calculated by summing over all possible conformations according to

28

 

<P> =
2 exp(-Ej/RT)
1

(Equation 4)
where Pj is the magnitude of the property P associated with the j-th chain in the sample,

and EJ- is the energy associated with the chain. The denominator in Equation 4 represents
the conformational partition function.
One of the common realistic models of hydrocarbon chain involves carbons

confined to the vertices of the diamond lattice.58 ‘59 '60

This model is simple enough to be
tractable for long chains, yet sophisticated enough to allow a wide variety of properties
of hydrocarbon chains to be calculated. Many of these features are contained within the
3-fold rotational isomeric state model (RIS model).6| According to the model, a
hydrocarbon chain is viewed as a molecule with fixed bond lengths and bond angles. The
rotational potential about each bond is accommodated into the model as a series of
discrete rotational states associated with the energy minima of the rotation (usually the
trans and two gauche states).

A number of approaches have been taken to develop general theories of
cyclization probability and cyclization dynamics.51 Fraser and Winnik59 showed a Monte
Carlo simulation on a diamond lattice (RIS model) that was used to estimate the

intramolecular cyclization probability of a bulky benzophenone connected to amine by a

polymethylene chain (24: a is a spherical reactive volume with diameter 3.1 A).

29

a»

24

C02(CH2)m—NH2

This probability determined the chain length dependence of relative rate

constants in exciplex formation between photoexcited amine and chromophore when the

intrinsic rate for this reaction is very low and therefore this cyclization is

conformationally controlled. Figure 7 shows end-to-end probability and the odd-even

oscillation are artifacts associated with the parity of lattice sites which designate the

reactive volume. This oscillation is a typical feature of R18 simulations.

 

 

 

 

o-
L 4.45.
3.0 T'ZQB'K
W0
()2.0r- -1-17
A >-
u
in
q
nob ”'8
YN
.v‘ \m
o _ . 41“ . 4 . 1 . 2°
10 20 30 40 50

CHAIN LENGTH

Figure 7. End-to-end cyclization probability W(O) of the molecules 24 as a function of
chain length. Curves labeled syn and anti describe the particular conformations of the

ester group in 24.

From ref. 59.

30

Shimada and coworkersm‘63 '64 have published an important series of papers
reporting on the kinetics of intramolecular electron exchange in the molecules containing
either two l-naphthyl or two phthalimide groups connected to methylene chains. A
simulation of the cyclization dynamics in these systems based on RIS model was
reported. An exact enumeration or Monte Carlo calculations were used to calculate the

distribution of end-to-end distances. Their results are shown in Figure 8.

 

 

1-0

{(r)

 

 

 

 

Figure 8. Distribution of the end-to-end distance r of l-naphthalene-(CHz),.-1-
naphthalene. The numbers in the figure represents the number of CH2 groups n in the
molecule. From ref. 62.

A distribution of end-to-end chain distances was shown by Closs and coworkers
in the recent study of spin and reaction dynamics in flexible polymethylene biradicals
(Figure 9).65 That procedure put the chain into a diamond lattice and constructed the
conformations by assigning each four—carbon fragment in the chain one of the three

dihedral angles: trans coplanar, plus gauche, and minus gauche.

31

0 5 1 I I I I I l I I I

0 15 20 25

 

B

 

I I I I I I I I I I I l

0 5 10 15 20 25

 

0 5 10 15 20 25

R (A)

Figure 9. Unnorrnalized histogram of end-to-end distance for n-alkane chains from the
Monte Carlo program. A total of 5x105 samples were taken for each of the three chain
lengths: (A) 8 carbon atoms, (B) 12 carbon atoms, (C) 18 carbon atoms. From ref. 65.

  

1.1) 11011111

mm. 9.2

were condu

certainly b

LA”; £3§5¢~33€£E

energy I
photoe'
mum
bind}
CKClUs
the bi

Can 0-

32

1.6 Monitoring System: Calculation of the Rate Constants

The energy transfer study can be accomplished in one of two ways:
spectroscopically or photochemically. Measurements of growth or disappearance of an
excited state signal by means of fluorescence, phosphorescence, or UV spectroscopy
were conducted in many studies described in this chapter. Such measurements would
certainly be feasible in our systems; but the photochemical approach we used seems to
be ideal for several reasons discussed below.

The Norrish type II reaction” 66 has proved to be an extraordinary tool for

. ,4 ,4 .
energy transfer studies45 6 755

and it was used in this work as well. The Norrish type H
photoelimination and cyclization of phenyl alkyl ketones proceeds exclusively via
intramolecular y—hydrogen abstraction by an excited carbonyl group, producing a 1,4-
biradical as a primary photoproduct.67 It is well known that the reaction comes
exclusively from the triplet excited state of the ketone. Depending on conformation of
the biradical, the further reactions are possible. When the p orbitals of the radical centers
can overlap, cyclobutanol is formed (usually 5-10%). When the p orbitals of the radical
centers are parallel to the B-bond, the bond will cleave to give an enol and an alkene (25-
40%) or the starting ketone by disproportionation (SO-70%).7 Carbonyl compounds
which have n,1t* triplet state as the lowest excited state abstract hydrogen efficiently. The
cause of this chemical reactivity is the singly occupied n orbital on oxygen. Hydrogen
abstraction can also occur from a 1t,1c* state but with a much lower rate. Inductive effects

of the of y and 5 substituents influence the rate of hydrogen abstraction as well.34 The

hydrogen abstraction reaction competes with energy transfer to an acceptor

throttle

clock“ to cl;

 

I
4715/? ‘/ '

ltllomgb ~

u

  
  

intersystem

formation.

May or:
intramc

donor

form

33

chromophore. The kinetics of the Norrish type II reaction was adopted as the “system
clock” to calculate energy transfer rate constants.

Scheme 7 shows a detailed kinetic analysis of the photochemistry of flexible
bichromophoric systems. The ketone donor is excited by irradiation into its singlet state
following by intersystem crossing into triplet state. It is known that the quantum yield of
intersystem crossing in aromatic ketones is nearly one.4 The efficiency of triplet
formation is barely lowered by competing processes from the singlet: fluorescence and
internal conversion. Those processes are same for both favorable (coiled) as well as
unfavorable (uncoiled) conformations. Coiled conformation allow through-space
intramolecular energy transfer from an excited donor to a ground state acceptor. If the
donor excitation is not quenched by the energy transfer, y—hydrogen abstraction occurs to

form a biradical.

A z
-0* k
D A» WM» . 0
Ph 100% Ph T-S ph
ii kH

0* H

3

”KICK—MA __", Singlet,“ —’
100% Ph/U\—/K/\
\:
\OH .
WA

k
/ j.

cyclobutanol I cleavage products I

 

 

Rate constar
te-
lm -

,1}-

1

Scheme 7. I

“here
rate (1
probal
llldlrm
general
1there g
WEDGE

34

Rate constants:
km - intramolecular energy transfer A - acceptor
kH - y—hydrogen abstraction TS - through-space

k-H - reverse hydrogen abstraction
kcyc - cyclobutanol formation (Norrish type H reaction)
ku - B-cleavage reaction (Norrish type II reaction)

Scheme 7. Photokinetics of a Bichromophoric System

Two measurements of phenyl ketone photochemistry provide insight into

understanding their behavior: the quantum yield and the excited triplet lifetime.

The quantum yield for the type II reaction can be expressed as:68

(Du = (DISC kHTPu (Equation 5)

where (DISC is the quantum yield of intersystem crossing from singlet to triplet, kH is the
rate constant for biradical formation, 1 is the lifetime of the triplet state, and Pu is the
probability that the biradical will collapse to give products. Triplet lifetime (I) is an
indirect measurement extracted from a steady state kinetics quenching experiment which
generates a Stem-Volmer plot.69 The Stem-Volmer expression is 90/9 = 1 + k.,to[Q],
where (1)., is the quantum yield in the absence of quencher, (l) is the quantum yield in the
presence of quencher, kq is the bimolecular rate constant for quenching, to is the life time

of the excited state being quenched, [Q] is the concentration of quencher.

Since (DISC = 1; HI = k” + kET;7O and provided that kH 2 107 s", the quantum

yield for the type II reaction (from Equation 5) can be expressed as (1)" = P" when energy

trusts r102-

transler con

transfer

the tr

S0 1hr

Vane

Smdic

35

transfer does no compete with y—hydrogen abstraction (kg = 0). In case that energy

transfer competes with kg, (1)“ can be written as:

(1)" = kH‘CPu = kHPu / (kH + kET) (Equation 6)

Thus, there are seven reasons why the Norrish type I] reaction is an excellent tool
for measurements of energy transfer rate constants in bichromophores:

1. Triplet excited ketone, providing both hydrogen abstraction and energy
transfer, guarantees that only triplet energy transfer is monitored (‘Prsc = l).

2. Hydrogen abstraction and energy transfer are essentially the only reactions of
the triplet ketone.

3. The rates of the abstraction and the transfer are of the same order in this work,
so the “system clock” provides reliable data. The rate of hydrogen abstraction could be
varied by changing the substituents on the benzoyl group.

4. Stem-Volmer quenching measurements are accompanied by quantum yield
studies which can verify their results.

5. Stern-Volmer technique is known to be of a high precision.

6. Quenching rate constants kq are known for large number of ketones.

7. Laser spectroscopy is difficult in the range of our lifetime measurements (1/t ~

108-109 s").

1.1 Gods

2:22sz 2' s‘

dominates

complex in.

Course
totron
llef
excitz
fiflet

and
naph'

BCCEF

allErat

large ir

36

1.7 Goals of Research

It was suggested that through-bond mechanism of intramolecular triplet energy
transfer is predominant in short flexible molecules while through-space mechanism
dominates in flexible medium-length—tether molecules.47 In order to obtain a more
complex insight into how ITET is influenced by all chain lengths, a comprehensive study
of the molecules with short, medium, and long tethers (4- to 15-atom tethers) has been
undertaken.

As mentioned earlier, character of chromophores may significantly affect the
course of the energy transfer between them.l Only bimolecular energy transfer“''5 and
intramolecular energy transfer in rigid molecules27 have been investigated systematically
in terms of electronic effects in the past. An influence of chromophore triplet energy E,
excitation type, excitation delocalization, and its ability for the orbital overlap on ITET
rate constants has been studied in molecules with different tether lengths. Acetophenone
and 4-methylacetophenone chromophores have been used as the donors, and 2-
naphthyloxy and 4-/3-/2-biphenyloxy chromophores have been examined as the
acceptors.

Regioselective character of chromophore approach has been studied by an
alteration of the tether length along with a modification of the chromophore character.

It has been known for a long time that a change of the tether character may have a
large impact on various intramolecular cyclizations and physical processes in flexible

molecules. 50'56'63 The polymethylene chain, -(CH2)n-, in a flexible molecule was replaced

by more

constants l.

37

by a more flexible polyethylene oxide, -(CH2CHZO)m-, and the differences in IT ET rate

constants have been investigated.

 

Scheme

2. RESULTS

2.1 General Information

2.1.1 Bichromophores

The compounds in Scheme 8 and 9 were prepared and used for this dissertation.

 

 

 

 

 

 

Scheme 8.
O
O (CH2)x-O-A
R
D-n-OA

Compound R A n = x
Bz-n-OPh H phenyl 3—5, 7, 10, 11
Bz-n-ONp H 2-naphthyl 3-7, 9-11, 14
Bz-n-O4Bp H 4-biphenyl 3-7, 9-11, 14
Bz-n-O3Bp H 3-biphenyl 3, 6, 7, 9, 10, 14
Bz-n-OZBp H 2-biphenyl 3-7, 9-11, 14
MeBz-n-OPh CH3 phenyl 3-5
MeBz-n-ONp CH3 2-naphthyl 3-7, 12
MeBz-n-O4Bp CH3 4-biphenyl 3
Bz = benzoyl.

38

Sthne‘l. -.

2.1.2 8

phenj

three

Prep:
(M111
N511 ll
maclic

{OHOM

Were Sir

Gné’nard

39

Scheme 9.
O

O (CH2)3-O-(CH2)2-O—A

D-3-O-2-OA

 

Compound A

 

Bz-3-O-2-OPh phenyl
Bz-3-O-2-O4Bp 4-biphenyl

 

 

Bz = benzoyl

2.1.2 Synthesis of Bichromophores

(o-Aryloxyalkanoaryl ketones D-(CH2)x-O-A (D = benzoyl, 4-methy1benzoyl; A =
phenyl, 2-naphthyl, 2—, 3-, 4-biphenyl, x = 3-11, 14) (Scheme 8 and 9) were prepared by
three different synthetic routes. Full synthetic procedures are describedin Chapter 4.

(o-Aryloxyalkanoaryl ketones D-(CH2)x-O-A (x = 3, 4) (Scheme 8 and 9) were
prepared by a standard Grignard reaction of the appropriate arylmagnesium bromide with
w-chloroalkanenitrile, followed by a nucleophilic substitution of chlorine by iodine using
NaI in acetone. The iodo ketone D-(CH2)x-I was converted into the bichromophore by
reaction of its ethylene glycol ketal with the appropriate sodium phenolate, A-ONa,
followed by a deprotection reaction.

(o-Aryloxyalkanoaryl ketones D-(CH2)x-O-A (x = 5-7, 11, 14) (Scheme 8 and 9)
were synthesized in the first step by a standard addition of the appropriate aryl bromide

Grignard with a cyclic ketone. The cycloalkyl hypochlorite was prepared from the

muting o.

nmhmgin

,z/
aeéfiifii

 

The prO'
was d3.
by re:
[Tin

phen}

(148

4lnp

into 3

tunoec

40

resulting cycloalkyl alcohol and then was subjected to photochemical ring opening7|
resulting in (o-chloro acyclic ketone D-(CH2)x-Cl in CC14. The yield in this step was
found to be very sensitive to stirring and dilution. Thus, mechanical stirring and a low
concentration of the starting material worked best. The final bichromophore was
prepared from the chloride in a series of nucleophilic substitution reactions similar to
those in the first procedure.

The synthesis of (o-aryloxyalkanoaryl ketones D-(CH2)x-O—A (x = 9-11) (Scheme
8 and 9) started by protecting the (ii-bromoalkanol Br-(CH2)x-OH with 2,3-dihydropyran.
The protected bromoalcohol reacted with the appropriate sodium phenolate. The alcohol
was deprotected and converted to A-O-(CH2)x—C1 using SOClz and then to A-O-(CH2)x-I
by reaction with NaI in acetone. The corresponding (o-aryloxyalkyl nitrile A-O-(CH2)X-
CN was synthesized from the iodide and NaCN in DMF. Reaction of the nitrile with the
phenyl Grignard Ar-MgBr provided the final bichromophores.

Dr. J. Qiao synthesized some ketones studied in this work: Bz-n-OPh and Bz-n-
O4Bp (n = 3-5).

y-(2—Aryloxyethyloxy)butyrophenones D-3-O-2-OA (D = benzoyl; A = phenyl or
4-biphenyl) were synthesized in four steps, starting with a conversion of 2-chloroethanol

into 2-aryloxyethanol, followed by reaction of its sodium salt with y-iodobutyrophenone.

All bichromophores were recrystallized from hexane/ethyl acetate mixtures and

purified by flash chromatography when necessary. Their purity was 99%+ in all cases,

41

except for compounds with the 3—biphenyl group as the acceptor which contained 2-3%

of their 4-biphenyl isomers.

2-2 Photokinetic Measurements

Cyclohexane or benzene 0.001 M solutions of a bichromophore with different
concentrations of the quencher (2,5-dimethyl-2,4-hexadiene) were irradiated at 366 nm
where only donors absorb. Valerophenone 0.001 M solutions were irradiated
Simultaneously as actinometer ((1)11 = 0.3)72 for quantum yield measurements.73 Triplet
lifetimes (1) were determined by Stem-Volmer steady-state quenching techniques69 that

gave straight lines whose slopes were equal to W- All Stem-Volmer plots were linear
W i th correlation coefficients 0.97-0.99. The type H photoproduct yields (acetophenone or
4—l‘nethylacetophenone) were determined by HPLC; conversions were always kept under
1 5%. The olefinic coproduct from the photocleavage was not analyzed. Minor HPLC
Peatks, observed in some ketones, were assumed to be cyclobutanol coproducts but were
“or analyzed.
Tables 1 - 3 list Norrish type H quantum yield, kg and III values for all systems.
Quantum yields were corrected for optical density at 366 nm in cyclohexane or benzene.
Some bichromophores used in this work were not very soluble in cyclohexane and

therefore it was difficult to obtain precise optical density and molar absorptivity values in

 

42

this solvent. For many long molecules, 0.001 M concentration was nearly a saturated
solution and their molar absorptivity values in cyclohexane were interpolated from their
values in benzene. Typical values of molar absorptivities 8366 were as low as
3-5 Lmol"cm". Reciprocal lifetimes III were calculated from kg: and the known
bimolecular rate constants (kq) 8x109 M"s'l for cyclohexanen’74 and 6x109 M"s'l for

4
benzene.7

Table l. Photokinetics of Model m—Phenoxy Ketones in Cyclohexane“

 

 

 

 

D-n-OA <1)" kq‘t, M'1 m, 108 s"
Bz-3-0Ph 0.45:0.00 30.7:04 2.6
Bz-4-0Ph 0.44:0.01 232.4i16.0 0.34
Bz-S-OPh 0.351001 89.5i0.3 0.89
Bz-7-0Ph 0.29i0.00 62.4i2.3 1.3
Bz-lO-OPh 0.26:0.01 57.3:12 1.4
Bz-l l-OPh 0.26i0.01 58.2i0.4 1.4
MeBz-3-0Ph 0.61i0.02 153.4127 0.50
MeBz-4-0Ph 0.56:0.02 1090.6:873 0.07
MeBz-S-OPh 0.43:0.02 412.4:15 0.19
Bz-3-O-2-0Ph 0.44:0.01 24.7116 3.2

 

 

 

 

 

 

Measured at room temperature; the devratron values are reproducrbrlrty from two
measurements.

Table 2. Photokinetics of Naphthyloxy Ketones in Cyclohexane“

43

 

 

 

 

 

 

 

D-n-OA on kqt, M" m, 108 s"
Bz-3—0Np 0.13:0.00 42:01 19.0
Bz-4-0Np 0.04:0.00 163:05 4.9
Bz-S-ONp 0.16:0.00 19.5:0.1 4.1
Bz-6-0Np 0.16:0.00 22.2:0.7 3.6
Bz-7-0Np 0.17:0.00 23.2:00 3.4
Bz-9-0Np 0.11:0.02 15.0:1.4 5.3
Bz-lO-ONp 0.13:0.01 13.6:1.1 5.9
Bz-l l-ONp 0.18:0.00 24.7:02 3.2
Bz-l4-ONp 0.15:0.00 308:3.0 2.6
MeBz-3-0Np 0.03:0.00 34:00 23.5
MeBz-4-ONp 0.01:0.00 15.7:0.2 5.1
MeBz-S-ONp 0.03:0.00 203:0.0 3.9
MeBz-6-0Np 0.04:0.00 23.7:06 3.4
MeBz-7-0Np 0.05:0.00 25.8:1.1 3.1
MeBz-l l-ONp 0.06:0.00 28.8:1.6 2.8

 

“Measured at room temperature; the deviation values are reproducibility from two

measurements.

 

44

Table 3. Photokinetics of Biphenyloxy Ketones with in Cyclohexane“

 

 

 

 

 

 

 

 

 

 

D-n—OA <0" kqt, M" 1/1, 108 s'1
Bz-3-O4Bp 0.17:0.02 77:06 10.4
Bz-4-O4Bp 0.05:0.00 207:0.3 3.9
Bz-5-04Bp 0.13:0.00 27.3:09 2.9
Bz-6-O4Bp 0.14:0.00 30.4:02 2.6
Bz-7-O4Bp 0.17:0.01 32.5:01 2.5
Bz-9-O4Bp 0.13:0.00 205:0.2 3.9
Bz-lO-O4Bp 0.07:0.01 23.3:0.4 3.4
Bz-l 1-0413p 0.21:0.01 33.4:07 2.4
Bz-l4-O4Bp 024:000” 28.4:02” 2.1
Bz-3-O3Bp 020:000 10.1:01 7.9
Bz-6-O3Bp 0.17:0.01 32.8:0.2 2.4
Bz-7-O3Bp 0.18:0.01 27.5:00 2.9
Bz-9-O3Bp 0.15" 36.1" 2.2
Bz—10-03Bp 0.18:0.01 28.6:01 2.8
Bz—14-O3Bp 0.17:0.00 35.7:0.5 2.2
132-3-02131) 0.23:0.01 119:01 6.7
Bz-4-02Bp 0.05:0.00 36.7:0.0 2.2
Bz-5-02Bp 0.17:0.00 32.5:0.3 2.5
Bz-6-02Bp 0.13:0.00 25.7:06 3.1
Bz-7-02Bp 0.13:0.00 216:04 3.7
Bz-9-O2Bp 0.13:0.01 298:06 2.7
Bz-lO-OZBp 0.13:0.00 23.9:09 3.3
Bz-l 1-02Bp 0.19:0.01 35.7:20 2.2
Bz—14-02Bp 0.20:0.01 39.2:06 2.0
MeBz-3-043p 0.04:0.00 89:01 9.0
Bz-3-O-2-O4Bp 0.17:0.00 105:0.9 7.6

 

“Measured at room temperature; the deviation values are reproducibility from two

measurements. bIn benzene. "Single measurement.

 

45

2.3 Calculations

In order to gain a better understanding of our experimental results, molecular
mechanics (MM2) and semi empirical (AMI) calculations were conducted. CS Chcm3D
Pro(tm), version 3.5.1, has been used in all calculations. The AMI protocol was used
from the CS MOPAC Std(tm), version 3.5.1.

Minimizations (semi empirical AMI calculations) were performed to get
information about the distance between the donor and acceptor chromophores in a fully

stretched molecule. Such conformation provides the largest distance possible (Figures 10

and 11).

./
\/

/

 

 

 

O O-

6

Figure 10. AM] minimized structure of Bz-3—O-2Np showing the distance between the
carbonyl oxygen and the closest carbon of the naphthyl group.

46

   
 

\.
C

    

 

O 0’.
0/

11.213.

Figure 11. AM] minimized structure of Bz-7-O-2Np showing the distance between the
carbonyl oxygen and the closest carbon of the naphthyl group.

IS”

3. DISCUSSION

This chapter discusses the significance of the experimental results and presents
the conclusions of our study. Scheme 10 is an example of both energy transfer and the

Norrish type II reaction in a representative bichromophore system in this work.

W30
w” QM”
W” 6* ~

Scheme 10.

3.1 Thermodynamics

Intramolecular as well as intermolecular triplet-triplet energy transfer rates are
known to be dependent on interchromophore energy gap (AB) (Chapter 1). The AE can

be measured in two ways: (a) from the phosphorescence spectra of independent

47

48

chromophores or (b) by energy transfer measurements. The two do not always

75 .76

correlate, because rate constants are dependent also on other factors. Frerking

concluded that AE values derived from phosphorescence spectra in his diketone study
were generally higher than those derived from energy transfer rate constants.75

Thus, the energy gap AE can be express by the equation:

AB = ET(donor) - ET(acceptor) (Equation 7)

where ET(donor) is triplet energy of the donor and Efiacceptor) is triplet energy of the
acceptor.

Energy transfer in all molecules reported in this work is exothermic and
practically irreversible.4 In order to achieve a specific excitation of the donor,
cyclohexane or benzene solutions of ketones were irradiated at 366 run where the
acceptors, 2-naphthyloxy and biphenyloxy chromophores (8366 2 0.1 Lmol"m"), barely

absorb. Triplet levels ET of the donor and the acceptor chromophores are listed in

Table 4.

Table 4. Triplet levels ET of the donor and the acceptor chromophores

 

 

 

Chromophore ET (kcal/moi)
benzoyl 7277
4-methylbenzoyl 7378
2-naphthyloxy 6279
4-biphenyloxy 6880
3-biphenyloxy 6980
2-biphenyloxy 6980

 

49

3.2 Energy Transfer Rate Constants

Norrish type 1] reaction was used as a tool for energy transfer studies in this work
(Chapter 1). Two measurements of Norrish Type II photochemistry provide
understanding its behavior: (a) the excited triplet lifetime, I; and (b) the quantum yield of
the reaction, (1).

Energy transfer rate constants (kg) were calculated from triplet lifetimes
determined by Stem-Volmer quenching and from quantum yield measurements (Tables
5, 6). Determination of yhydrogen abstraction rates (kH) in bichromophores from those
data is crucial for kET calculations because its rate competes only with energy transfer
(Scheme 10). Two different calculations were applied in which kg; were obtained from:
(a) III of model phenoxy ketones or (b) quantum yields. They are fully discussed below.

Quantum yields and triplet lifetimes of six model phenoxy ketones (Bz-n-OPh for
n = 6, 9, l4; MeBz-n-OPh for n = 6, 7, 1 l) were interpolated from the values obtained in

the photokinetic measurements of the other model phenoxy ketones (Table l).

50

Table 5. Intramolecular Energy Transfer Rates in Naphthyloxy Bichromophores
Obtained from Stem-Volmer and Quantum Yield Measurements.

 

 

 

D-n-OA km“, 108 s" km", 108 s"
Bz-3-ONp 16.3 13.5
Bz-4-ONp 4.5 4.5
Bz-5-0Np 3.1 2.2
Bz-6-0Np 2.5 1 .9
Bz-7-0Np 2.0 1.4
Bz~9-ONp 3.8 3.2
Bz-lO-ONp 4.4 3.0
Bz-l l-ONp 1.7 ‘ 1.0
Bz-l4-ONp 1.1 1.1
MeBz-3-ON p 22.9 22.3
MeBz-4-ONp 5.0 5.0
MeBz-S-ONp 3.6 3.6
MeBz-6-0Np 3. 1 3. 1
MeBz-7-0Np 2.8 2.7
MeBz-l 1-0Np 2.5 2.3

 

 

 

 

 

“Rates kn obtained from 1/1 of model phenoxy ketones. ”Rates k" obtained from
quantum yields.

51

Table 6. Intramolecular Energy Transfer Rates in Biphenyloxy Ketones Obtained from
Stem-Volmer and Quantum Yield Measurements.

 

 

 

 

 

 

D-n-OA km“, 108 5" km", 108 s“
Bz-3-O4Bp 7.8 6.5
Bz-4-O4Bp 3.5 3.5
Bz-5-O4Bp 2.0 l .8
Bz-6-O4Bp 1.6 1.5
Bz-7-O4Bp 1.2 1.0
Bz-9-O4Bp 2.5 2.1
Bz-10—O4Bp 2.0 2.5
Bz-1 1-043p 1.0 0.5
Bz-14-O4Bp 0.7" 02"
Bz-3-O3Bp 5.3 4.4
Bz-6-O3Bp 1.4 l .2
Bz-7-O3Bp 1.6 1.1
Bz-9-O3Bp 0.8 1.0
Bz-10-03Bp 1.4 0.9
Bz-14-O3Bp 0.8 0.8
Bz-3-02Bp T 4.1 3.3
Bz—4-O2Bp 1.8 2.0
Bz-5-02Bp 1.5 1.3
Bz-6-02Bp 2. l 1.9
Bz-7-02Bp 2.4 2.0
Bz-9-02Bp 1 .3 1 .4
Bz-lO-O2Bp 1.9 1.7
Bz—l 1-O2Bp 0.8 0.6
Bz-14-02Bp 0.6 0.5
MeBz-3-O4Bp 8.5 8.4
Bz-3-O-2-O4Bp 4.4 4.7

 

 

 

 

 

“Rates k“ obtained from 1/1.’ of model phenoxy ketones. bRates kn obtained from
quantum yields. CIn benzene.

52

(a) k” obtained from [/1 of model phenoxy ketones

'y-Hydrogen abstraction is presumed to be the only reaction observed in the model
phenoxy ketones. Those compounds provide information about the quantum efficiencies
and the rate constants for the photoelimination reaction in the absence of triplet energy

transfer because transfer to the phenoxy group (ET ~ 81 kcal/mol)81 is highly
endothermic and charge transfer quenching by anisole is slow.82
When kg in the model compound is assumed to be equivalent to that in the

corresponding bichromophore, intramolecular energy transfer rate constants km can be

calculated according to Equation 8,
kET = “I - kH - k2 [K] (Equation 8)

where I is the triplet lifetime of the bichromophore, k“ is 1/1 of the corresponding model
ketone, k2 is the calculated bimolecular quenching (8x106 M'ls'l for 2-naphthyloxy
ketones; 3x106 M'IS‘l for biphenyloxy ketones),15 and [K] is the bichromophore
concentration. Bimolecular quenching rates were about 2 orders of magnitude lower than
those of intramolecular because ketone concentrations were 0.001 M. It does not
contribute significantly to decay and could be neglected in our calculations.

Intramolecular energy transfer rates for all bichromophores are listed in Tables 5 and 6.

(b) k” calculated from quantum yields
The values kn and P" depend on the aromatic acceptor in D-n-OA, especially in
those with 3- and 4-methylene tethers. It is known that Norrish type II intramolecular

abstraction of y—hydrogen atom is strongly dependent on inductive effects of y and 5

53

substituents.34’68 Thus, the rate constants k” may be different in model compounds and in

bichromophores.

The quantum yield of Norrish type H reaction can be expressed as
(1)" = (DISC kHTPu (Equation 9)68

where (DISC is the quantum yield of intersystem crossing from singlet to triplet, kH is the
rate constant for biradical formation, 12 is the lifetime of the triplet state, and Pu is the
probability that the biradical will collapse to give products. Since (DISC is equal to one34
and 1/1: = kH + km,70 provided that there are no other reactions of the excited ketone,
energy transfer rates can be calculated from kH derived from the quantum yields.68 The
value 1/1' really equals (kH + kET + kx), where kx is the rate constant for any other

reaction. The quantum yields in Tables 1-3 then provide direct information about kH in

the bichromophoric systems.

The quantum yield in the absence of energy transfer in model phenoxy ketones
can be expressed as <I>n° = Pu (Chapter 1.4). Since the quantum yield in bichromophore is
(Du = kan (Equation 9), kn = 1/t.<l>"/ (Duo. The rate constants for hydrogen abstraction

(kg) and consequently energy transfer rate constants (kg) were calculated from Equation

10.
kET = l/T — (Du/ (13110.1/1: (Equation 10)

Energy transfer rate constants calculated from quantum yields and reciprocal
lifetimes of bichromophores according to Equation 10 are listed in Tables 5 and 6. The

accuracy of the quantum yield measurements is assumed to be not as high. Stem-Volmer

54

calculations are statistically more precise because each measurement consists of 20
independent HPLC measurements while quantum yield experiments only of 4.
Benzophenone triplets are quenched by anisole via exciplex83 with bimolecular
rate constant 3x106 M'ls'l, two orders of magnitude slower than average intramolecular
rate constant in our systems. Charge transfer quenching of acetophenone by anisole is
known to be slow too.82 However, intramolecular quenching in short model phenoxy
ketones (Bz-3-0Ph, MeBz-3-0Ph) could be more significant and cause lower quantum
yields and consequently lower calculated rate constants. This assumption has to be

proved by further research.

3.3 Flexibility of the Tether

Figure 12 compares intramolecular energy transfer constants for three
bichromophoric systems Bz-n-ONp, Bz-n-O48p, and MeBz-n-ONp with those of Closs’
rigid molecules27 in which the benzophenone donor and the naphthalene acceptor are
attached to a rigid spacer (cyclohexane or decalin ring) in all-equatorial positions. Closs
showed that in such isomers with two anti dihedral angles, through-bond energy transfer
rate constants are higher about one order of magnitude than in those with substituents in
equatorial-axial positions (i.e. anti-gauche).

The rate constant in Bz-3-0Np is nearly identical to that of the Closs’ rigid

benzophenone-naphthalene system (Figure 12) as well as Cowan’s flexible benzoyl-

55

styryl bichromophore37 in which chromophores are separated by four atoms. We
conclude that through-bond interaction predominates in all flexible 4-atom tether
molecules. In systems with 5-atom tether, overall energy transfer rate constants are
higher by about a factor of 5 than in that of a rigid bichromophoric molecule. Molecular
flexibility apparently produces some conformations in which the two chromophores are
close enough that through-space contribution becomes competitive with through-bond
interaction. Such coiled conformations contain predominantly gauche rotation states
which lower through—bond transfer but raise through-space interaction. For longer '
molecules, Figure 12 and especially the insert suggest that more than 99% of the total
energy transfer occurs through space. Thus, the rate constants in longer flexible systems
no longer fall an order of magnitude per additional bond, as they do for molecules with
rigid spacers.

Rates in flexible molecules are still remarkably high in long derivatives - only
one order of magnitude lower than those in molecules with 4-atom tethers. Long distance
through-bond triplet energy transfer was found to be 25 s'1 in rigid steroid molecule in
which the benzophenone donor is separated by 10 atoms from the naphthalene

84

acceptor. This rate constant is 7 orders of magnitude smaller than that of the

corresponding flexible derivative Bz-9-ONp (kET = 3.8x108 5").

56

 

 

       
     

 

 

 

 

     

‘1 1 r l -' 1
Fl l l T
9!l-fi° -
.A
7—\
A
\
8.9 -
3.5— x —
logk \\
ET 1 1 Li L
8.5-. 57101214..
‘1 Q (n+1)
'\
\
I
8.1 - iA
1
l 1 1 1 1 ,

 

 

4 6 8 10 12 14

Number of Atoms between Chromophores

Figure 12. Rate constants for triplet energy transfer as a function of the number of atoms
connecting donor and acceptor: O Bz-n-ONp; O MeBz-n-ONp; I Bz-n-OBp; A 4-
PhCOPh-"rigid spacer”-2Np from ref. 27. Bz-n-ONp and the rigid molecule rate
constants (from refs. 27, 84) are shown in the insert.

Energy transfer rate constants in Figure 12 level off to some extent in molecules
with seven or more atoms between chromophores. We conclude that conformational
factors produce a nearly constant percentage of geometries with the two chromophores
close enough for through-space energy transfer. Similar plateaus have been observed in
studies on electron transfer in bichromophoric radical anions,85 spin-orbit exchange

interaction in biradicals,86 and many cyclization reactions.“ Monte Carlo calculations of

Closs, Forbes, and coworkers87 as well as exact enumeration calculations of Sisido and

57

Shimada88 proved that even for very long molecules, which have 10 to 25-atom tethers,
there is still a certain fraction of conformations allowing a close proximity of both ends.
This fraction is certainly very small. A crude comparison of our plateau intramolecular
energy transfer rate constants (kET ~ 108 8") with those of bimolecular in-cage transfer
constants (kET ~ 5-10x1010 s")89 ’90 or the rate of diffusion-controlled exothermic triplet

transfer when donor and acceptor were 3-4 A apart (kET ~ 10'2 8")91

suggests that the
fraction should be smaller than 1%.

Intramolecular triplet energy transfer occurs over longer distances than do
intramolecular bond formations. Plot in Figure 12 lacking the characteristic rate constant

92 reflects such difference. Exothennic bimolecular

profile of cyclization reactions“
energy transfer between corresponding chromophores used in this work is nearly
diffusion controlled. Analogous intramolecular processes can be controlled by bond
rotation kinetics and/or by ground state conformational equilibria.7 Since excitation of
the carbonyl chromophore should not alter conformational equilibria, most of the energy
transfer occurs in conformers already sufficiently coiled before excitation. Each
conformation has its own probability of undergoing energy transfer that depends mainly
on the distance between chromophores and their orientations. Thus, the observed rate
constant of an intramolecular process is a weighted average over all favorable
conformations.93

All conformers whose chromophores are 6 A or less apart should contribute to

the total transfer. When the chromophores are within 3-4 A, energy transfer is practically

instant (km ~ lO”-10l2 8")89‘90'9| and provides the intramolecular equivalent of static

58

quenching. When the interchromophore distance is 5-6 A (km ~ 108-109 8")94 some
unfavorable conformers may rotate into such static quenching geometries within donor
lifetime. Energy transfer in those cases competes with hydrogen abstraction (kET ~
108 s").

The intramolecular energy transfer rate constant in the bichromophore Bz-3-O-2-
O4Bp is higher by about a factor of three than that of the analogous Bz-6-O4Bp, having
also 7-atom tether (Table 6). As was depicted in other examples,“95 the exchange of a
methylene group for oxygen increases flexibility of the chain thanks to a reduction of the
gauche torsional strain.

Figure 13 depicts five characteristic model situations in which energy transfer
rate constants depend on interchromophore distance or ability of the system to bring
them close within the lifetime of the donor. The D-A distance 3 A in the conformation A
suggests that the energy transfer is instant (210H 8"). Rotation along one C-C bond in B
will bring the acceptor as close to the donor as in A. Such conformer may have a
sufficient time to rotate into a favorable geometry within the lifetime of the benzoyl
donor (Tables 2, 3) provided that the rotation rate constant is at least 109 s". The DA
distance 6 A in C corresponds to energy transfer rate constant 108 s". In both systems B
and C, energy transfer competes with Norrish type II hydrogen abstraction. In the totally
stretched conformation D, the donor and the acceptor are about 14 A apart what prevents
energy transfer. The special case E shows a typical low energy “W” conformation”96 in
which donor and acceptor are not in close proximity and/or their orientations are not

favorable. However, through-space (solvent) energy hop from the chromophore to a

59

chain atom (eventually from chain to chain) might contribute to the total energy transfer.
The transfer rate constant is assumed to be high because the total transfer path is about
4.5 A. The calculations of electronic coupling in the rigid systems using ab initio MO
theory revealed that paths involving hops which skip over bonds make largest
contribution to the total through-bond coupling.97 Energy and electron transfer hops in

proteins are currently at the center of interest.98

 

3A
6A
0* o 0* 0* A‘o
A B C
’1
3131 0
14A /
= *5 D*
W ’A
*D o
D E

Figure 13. Five characteristic conformations of D-9-OA: the simplified model.

60

3.4 Electronic Factors

An unexpected jump in energy transfer rates for Bz-x-O-2Np and Bz-x—O-4Bp
with 10- and ll-atom tethers in Figure 12 indicates a larger number of conformations
which allow through-space intramolecular energy transfer. Both systems exhibit the

same profile for the dependence of km on tether length.

 

 

 

1 1 1 r I 1 1 75
9.4 _
9 -' - 7
logkET logP
8.6 —
- 6.5
8.3 '
7'9 P 1 1 1 1 1 1 1
6

 

 

4 6 8 10 12 14 16
Number of Atoms between Chromophores (n+1)

Figure 14. Rate constants for triplet energy transfer, km, and for electron transfer, P, as a
function of the number of atoms connecting the donor and the acceptor: O Bz-n-ONp; II-
phthalimide-(CH2),,+1-phthalimide from ref. 85.

61

Since the structure of the 2-naphthyl group resembles that of 4-biphenyl, as will
be discussed later in this dissertation, electronic effects seem to be the only factors
causing differences in behavior of these two bichromophores. Szwarc and coworkers85
investigated electron exchange between two phthalimide groups connected by a
polymethylene chain. Their results are in good agreement with our observations as
shown in Figure 14.

Intramolecular energy transfer rates in Figure 12 are consistently lower for the 4-
biphenyl chromophore compared to the naphthyl group approximately by a factor of two.
It is known that the lowest energy conformation of the biphenyl ground state in solution
is twisted while in the T1 state the two rings are coplanar.99 The conformational change
in biphenyl slows energy or electron transfer because of unfavorable Franck-Condon

- ~ 1 .99
factors as was shown in some bimolecular 5 a

and intramolecular energy transfer'oo
studies. This effect is independent of whether through-bond or through space interaction
predominates.

Benzoyl donor has an n,1t* lowest triplet excited state while 4-methylbenzoyl has

a 7t,7t"‘.34 A 1t,1t* excitation is more delocalized and 7t-1t overlap of the chromophores

should be geometrically more efficient than n-tr overlap because of a parallel geometry,

- - - 01
same character of orbitals, and less steric hindrance.I

The rate constants in Figure 12
are higher by a factor of only 1.2 to 1.5 for all tether lengths when a 4-methylbenzoyl
group (MeBz-n-ONp) rather than a benzoyl group (Bz-n-ONp) is the donor. The

difference is very small but consistent and a shift from through-bond to through-space

mechanism obviously does not play any role in this case. The rate constant for MeBz-3-

62

O43p (Table 6) is a bit higher than that of Bz-3-O4Bp too. Thus, a better excitation
delocalization and possibly a better orbital overlap seem to have a little effect on energy
transfer. Figure 15 suggests that not only delocalization but also a change of
chromophore orientation in the course of the transfer should be detectable. When only
1t,1t* excitations are involved, electron exchange is linked to n-type orbitals only. For
n,1t* excited benzoyl, however, one electron jumps from 7t* orbital of the donor into 1t*
orbital of the acceptor while the other has to jump from it orbital of the acceptor into n
orbital the donor. Such exchange involves a change of orbital orientation during the
process. Aromatic systems are parallel in 1t-1t interaction but the interaction between it
and n orbitals is best when the systems are perpendicular.83 Those are, of course, extreme
situations and it is logical that even geometries being far from ideal orientation might
allow electron transfer.'02 Nevertheless, the difference between benzoyl and 4-

methylbenzoyl donors was found to be very small.

63

‘ (CH2)x
o g W 0/

Figure 15. An example of the difference between n-n and 1H: interactions.

 

3.5 Isomeric Differences

When we compare molecules having the benzoyl donor connected to 4-, 3-, or 2-
substituted biphenyloxy groups (Figure 16), there are three characteristic regions in the
graph to be discussed.

All derivatives with 4 to 6-atom tether display parallel reactivity. It is known that
the barrier to rotation in 2-biphenyl substituted group is significantly higher than in those

of 3-biphenyl and 4-biphenyl substituted groups thanks to steric reasonsm Alkyloxy

64

group that is attached to ortho position of biphenyl interacts with ortho hydrogens of the
other ring when both rings are coplanar. Thus, conformational change from twisted
ground state into coplanar triplet in 2-biphenyl group is more energetically difficult than
in other biphenyls and Franck-Condom factors slow energy transfer even more. On the
other side, the ortho but especially para electron-donating alkyloxy groups stabilize the
planar rotation transition state by increasing the electron density at the carbon in the
pivot bond. This stabilization is a consequence of the resonance effect in the ground state
that decreases the rotational energy barrier.'03 An alkyloxy substituent in meta position
has apparently no electronic influence by resonance. We conclude that 2-biphenyloxy
acceptor lowers energy transfer rates because of steric reasons and that 4-biphenyloxy
ketones have higher rate constants thanks to buttressing resonance effect, totally absent
in 3-biphenyl derivatives.

The behavior of the longest derivatives (11 to lS-atom tether) is comparable to
those of the short tethers. Kinetics of energy transfer in these molecules evidently
resembles energy transfer in the corresponding bimolecular reactions. Diffusion is
replaced by molecular mechanics of very flexible system. This is another example of the
phenomenon that all effects influencing triplet energy transfer rates have comparable

impact regardless which mechanism, either through-bond or through-space, is involved.

65

 

8.8
8.6
log kET 8,3
8.1

7.8

 

 

l l l l l l

 

 

4 6 8 10 12 14

Number of Atoms between Chromophores (n+1)

Figure 16. Rate constants for triplet energy transfer, km, as a function of the number of
atoms connecting the donor and the acceptor: I Bz-n-O4Bp; V Bz-n-O3Bp; D Bz-n-
O2Bp.

More complex situation was observed in the medium-tether molecules. In the
region of 7 to lO-atom tethers, all molecules show a rate constant jump which occurs at
different tether length depending on the acceptor. According to Figure 16, the jump
began in bichromophores: Bz-6-O2Bp (7—atom tether) and Bz-9-O43p (IO-atom tether).
Bz-n-O3Bp has a similar rate constant profile as Bz-n-O2Bp. On the other hand, the rate

constants in Bz-9-O3Bp and Bz-9-OZBp dropps by a factor of two compared to Bz-9-

O4Bp.

66

Energy transfer rate differences in short as well as long bichromophores with a
biphenyloxy acceptor have been explained in terms of electronic and steric reasons. In
medium tether molecules, a rotation along a single bond in the chain could rationalize
their complex behavior. Figure 17 analyses a hypothetical example of one fixed
conformation in which C-O rotation is the only change of geometry. Three different
acceptors are compared in terms of a “reactive volume” originating from the rotation.
Such “reactive volume” has a meaning of energy transfer possibility. Orientation of
chromophores is crucial and not every rotamer is favorable for energy transfer.

The position of the phenyl ring attached to oxygen in biphenyl as well as
naphthyl acceptors is not influenced by the rotation and is identical for all of them. The
more distant phenyl in the 4-biphenyl and 2-naphthyl chromophores (F, G; Figure 17) is
obviously too far from the carbonyl donor; its position remains constant during the
rotation and so it has negligible contribution to energy transfer. Rotation of the 3-
biphenyl and especially 2-biphenyl (H; Figure 17) groups can, however, cause that the
more distant ring approaches the donor close enough to provide efficient energy transfer.

Let us assume that orientation of all phenyl rings in biphenyl and naphthyl
chromophores has the same statistical distribution. In this crude model, in which we
would like to analyze individual transfer contribution of each phenyl ring in the acceptor,
we assume that whenever one ring has favorable orientation, the other has too. Thus, this
approximation considers orientation effect relatively unimportant. On the other hand,
distance between the more distant phenyl and the donor strongly depends on the structure

of the acceptor. The second phenyl in 4-biphenyl chromophore is totally ineffective. In 2-

67

biphenyl, however, 50% of all favorable geometries of the phenoxy ring place the more
distant phenyl into favorable orientation and distance. It is clearly shown in Figure 17
that the more distant phenyl is significantly closer to the carbonyl donor (2.5 A) than the
phenoxy ring. This means that energy transfer should be significantly higher for 2-
biphenyloxy bichromophore (F) than in that of 4-biphenyloxy derivative (H). Energy
transfer rates in Bz-6-O4Bp and Bz-7-O4Bp were found to be higher than in those of Bz-
6-02Bp and Bz-7—O-2Bp by factors of 1.3 and 2, respectively (Table 6, Figure 16). The
C-O rotation evidently would not affect transfer when through-bond mechanism is
involved or when the tether is long enough that molecular dynamics masks such small
structural differences. This conformational analysis based on only one example is very
crude. But it is apparent that study of rotation along C-O bond in different geometries
and rotation along some other bonds could bring similar conclusions. Such systematic
study would require a detailed statistical investigation. The donor chromophore is
discussed as a group without specific orientation demands in this paragraph. This is

another approximation that has to be taken into consideration.

68

   

F G H

Figure 17. Rotation along the O-C terminal bond showing a “reactive volume”: Bz-6-
O43p (F), Bz-6-ONp (G), and Bz-6-02Bp (H).

Intramolecular energy transfer rates for Bz-x-O4Bp (x = 6,7) are smaller than in
those of Bz—x-O2Bp by approximately a factor of two (Table 6). Figures 18 and 19 show
an example of two minimized geometries for two bichromophores - Bz-6-O4Bp and B2-
6-02Bp - that illustrates another rationalizing in search for differences between 4-
biphenyl derivatives on one side and 2- or 3-biphenyl derivatives on the other. The
structure in Figure 18 demonstrates a situation when the phenoxy ring in 4-biphenyl is
about 5 A from the carbonyl oxygen but it is difficult to find a low energy conformation
in which the other ring would approach the donor as close. In Bz-6-OZBp (Figure 19)
where the tether is even more stretched than the other one, the conformation allows the

more distant ring to be in a close proximity to the carbonyl oxygen. Those geometries

69

are, of course, two among thousands possible and only very detailed statistical analysis
can provide definitive solution for this problem. The present reasoning provides,

however, another good explanation of this unusual and novel observations.

 

Figure 18. Representative example of the minimized geometry by MM2 calculation and
the formal structure of Bz-6-O48p.

7O

 

Figure 19. Representative example of the minimized geometry by MM2 calculation and
the formal structure of Bz-6-O2Bp.

71

3.6 Summary

This study presents a consistent picture of the intramolecular triplet energy
transfer in flexible molecules with all tether lengths. Various factors have been changed
in order to get information about how energetics, sterics, and dynamics influence the
course of the transfer. Much has been learned in this work regarding the difference
between through—bond and through space mechanisms. A remarkable finding, that even
as long as lS-atom-tether bichromophoric molecules still provide relatively fast energy
transfer, was presented. Further calculations are necessary for a more complete
understanding of how a change of the chromophore character and the molecular

dynamics affect energy transfer.

4. EXPERIMENTAL
4.1 Instrumentation

1H and 13C NMR spectra were obtained on either a 300 MHz Varian Gemini or
a 300 MHz Varian VXR—300 instrument.

IR spectra were recorded on a Nicolet IR/42 Fourier Transform IR spectrometer.
Samples were prepared using a pressed KBr disc technique.

UV spectra were recorded on a Shimadzu UV-160 spectrometer with matched
1.0 cm quartz cells.

High resolution mass spectra were obtained on a Joel JMS-HXllO double
focusing mass spectrometer in the MSU Mass Spectroscopic Facility. The electron
impact and direct probe methods were used.

HPLC analyses were performed on either a Rainin HPXL apparatus equipped
with a Dynamax UV-D absorbance detector or a Dynamax SD—200 system equipped with
a Dynamax Diode Array Detector PDA-l using a normal phase Rainin Microsorb Si80-
125-CS silica gel column and a 100 1.1L loop.

Gas chromatography analyses were performed on a Varian 3400 machine with
a flame ionization detector with a Hewlett-Packard 3395 integrating recorder.

Phosphorescence spectra were recorded on a Perkin-Elmer MPF-44A
fluorescence spectrophotometer with a Hewlett-Packard 3393A integrating recorder.
Spectra were recorded at 77K in a 2-methyltetrahydrofuran or ethanol glass in a 4 mm

Pyrex NMR sample tube.

72

73

Melting points were obtained on a Thomas Hoover capillary melting point

apparatus. Melting points are not corrected.

4.2 Preparation of Bichromophores

4.2.1 Synthesis of (o-Aryloxyalkyl Aryl Ketones
A. Synthesis of (o-Iodoalkyl Aryl Ketones from Cycloalkanones
(o-Iodoalkyl aryl ketones Ar-CO-(CH2)x-I (Ar = phenyl, 4-methylphenyl; x = 4-7,

1 1, 14) were prepared in three steps following the route given below:

 

Br R
1.Mg, E120
o = ..
2. O
R
(CH2)x
CH
( 2). 1.NaOCl, AcOl-I, CC14, 0°C
2. hv, reflux
O O

 

O (CH2)X_I Nal, acetone, l'CflllX 0 (CH2);Cl
R

Scheme 11. Synthesis of (o-Iodoalkyl Aryl Ketones

R

74

l-Phenylcyclopentanol

In a 250 mL three necked round bottom flask equipped with a condenser and
purged with argon a solution of the cyclopentanone (10.0 g, 0.1 mol) in diethyl ether (20
mL) was added dropwise to a solution of phenylmagnesium bromide, prepared from
phenyl bromide (16.5 g, 0.105 mol) and magnesium (2.7 g, 0.110 mol), in diethyl ether
(60 mL) at 5°C. After all the ketone had been added, the mixture was stirred at 25°C for
1 hr., and then 10% hydrochloric acid solution was added dropwise to the mixture until
all of the solid disappeared. The diethyl ether layer was separated and washed with
saturated sodium hydrogen carbonate solution, distilled water and dried over MgSO4.
Diethyl ether was evaporated to yield the crude product (70%). The product was used

without further purification in the next step.

I-Phenylcyclopentanol: 1H NMR(CDC13): 5(ppm) 1.5-1.8 (m, 8H), 7.2-7.6 (m, 5H).

Note: Due to poor solubilities of products with seven and more carbons in the
ring it was necessary to use more diethyl ether in this synthesis until the cycloalkanone

was all dissolved.

75

S-Chloro-l-phenylpentan-l-one'°4

A mixture of the l-phenylcyclopentanol (12.8 g, 0.08 mol), Clorox bleach (350
mL), and acetic acid (35 mL) in carbon tetrachloride (350 mL) was vigorously stirred at
0°C for 8 hours. Carbon tetrachloride layer was separated and aqueous layer was
extracted with carbon tetrachloride (3x 100 mL). The combined yellow carbon
tetrachloride layers were washed with saturated sodium hydrogen carbonate solution,
distilled water, and dried over MgSO4.

MgSO4 was filtered off and carbon tetrachloride (400 mL) was added. The
solution was then refluxed and stirred with mechanical stirrer under argon for about 12
hrs., initiated with incandescent lamp light. After the reaction was completed (the
product formation was monitored by either TLC or NMR) carbon tetrachloride was
evaporated and the crude product (85%) was purified by distillation.

Notes: Due to poor solubilities of products with 8 and more carbons in the ring it was
necessary to use more carbon tetrachloride during the extraction procedure. Those
compounds-were purified by crystallization.

5-Chloro-I-phenylpentan-1-one: 1H NMR (CDCl3): 5 (ppm) 1.8-1.9 (m, 4H), 3.0 (t,

2H), 3.6 (t, 2H), 7.4-7.9 (m, 5H).

S-Iodo-l-phenylpentan-l-one
A mixture of the 5-chloro-1-phenylpentan-l-one (13.8 g, 0.07 mol) and sodium

iodide (52.5 g, 0.35 mol) in dry acetone (600 mL) was refluxed for 24 hrs. in dark. The

76

solvent was evaporated and distilled water (300 mL) was added. The product was
extracted with diethyl ether (200 mL, 2x 50 mL), the combined ether layer was washed
with saturated sodium thiosulfate solution and distilled water, and dried over MgSOi.
The solvent was evaporated and the product was recrystallized from hexane/ethyl acetate
mixture (9:1). The yield was 95% and its purity was checked by TLC.

5-Iodo-I-phenylpentan-I-one: 1H NMR (CDC13): 5 (ppm) 1.8-2.0 (m, 4H), 3.0 (t, 2H),

3.3 (t, 2H), 7.4—7.9 (m, 5H).

B. Synthesis of 03-Aryloxyalkyl Aryl Ketones
0)-Aryloxyalkyl aryl ketones Ar-CO-(CH2)x-OAr’ (Ar = phenyl, 4-methylphenyl;
Ar’ = phenyl, 2-naphthyl, 2/3/4-biphenyl, x = 4-7, 14) were prepared in three steps

following the route given below:

 

O I I
O O
ethylene glycol,
(CH2)x—I PTSA, benzene (CH2);-I
R R
ArONa, DMF
O acetone, H20, H3O+, heat 0 O

 

O (CHz); OAr = 0 (CH2),— OAr
R R

Scheme 12. Synthesis of (o-Aryloxyalkanoaryl ketones (R = H, Me)

77

Ethylene glycol ketal of 5-iodo-1-phenylpentan-l-one

The mixture of the 5-iodo—l-phenylpentan-l-one (19.3 g, 0.067 mol), p-
toluenesulfonic acid (0.03 g), and ethyleneglycol (14.6 g, 0.23 mol) in benzene (60 mL)
was refluxed for 24 hrs. using a modified Dean-Stark trap and molecular sieve (4A). The
reaction was completed when the solvent over the sieve was clear. The solution was then
washed with saturated sodium hydrogen carbonate solution, distilled water, and dried
over MgSO4. The solvent was evaporated and the product (80% yield) was used in the
next step without further purification.
Ethylene glycol ketal of 5-iodo-I-phenylpentan-I-one: 1H NMR (CDCl3): 5 (ppm) 1.4-

1.9 (m, 6H), 3.2 (t, 2H), 3.8 (t, 2H), 4.0 (t, 2H), 7.4-8.0 (m, 5H).

Ethylene glycol ketal of 5-phenoxy-l-phenylpentan-l-one

A solution of ethylene glycol ketal of the 5-iodo-l-phenylpentan-1-one (17.6 g,
0.053 mol) and sodium phenolate, prepared from a phenol (50 g, 0.053 mol) and sodium
(1.3 g, 0.058 mol) in absolute methanol, in dimethylformamide (200 mL) was stirred at
50°C for 30 hrs. Distilled water was added (200 mL) and the product was extracted with
diethyl ether (3x 100 mL). The combined ether layer was washed with saturated sodium
chloride solution, distilled water, and dried over MgSO4. The solvent was evaporated

and the crude product (85%) was used in the next step without further purification.

78

Ethylene glycol ketal of 5-phenoxy-I -phenylpentan-1-one: 1H NMR (CDCI3): 5 (ppm)

1.3-1.9 (m, 6H), 3.7 (t, 2H), 3.8-4.1 (m, 4H), 6.9-8.0 (m, 5H).

5-Phenoxy-1-phenylpentan-l-one

A solution of ethylene glycol ketal of the 5-phenoxy-l-phenylpentan-l-one (13.5
g, 0.047 mol) and a catalytic amount of 10% hydrochloric acid in acetone (300 mL) was
stirred at 40°C for 24 hrs. Distilled water (300 mL) was added and the product was
extracted with diethyl ether (3x 100 mL). The combined ether layer was washed with
saturated sodium hydrogen carbonate solution, distilled water, and dried over MgSO4.
The solvent was evaporated and the crude product (75-80%) was purified by flash

chromatography and recrystallized from hexane/ethyl acetate mixture (8:2).

5 -Phenoxy- I -phenylpentan-1-one (Bz-4-OPh)

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.75-2.03 (m, 4H), 3.07 (t, J = 6.9 Hz,
2H), 4.01 (t, J = 6.0 Hz, 2H), 6.89 (d, J = 7.8 Hz, 2H), 6.93 (t, J = 7.4 Hz, 1H), 7.24-7.31
(m, 2H), 7.43-7.50 (m, 2H), 7.56 (t, J = 7.2, 1H), 7.97 (d, J = 7.4 Hz, 2H).

13'0 NMR (CDC13, 75 MHz): 8 (ppm) 20.93, 28.82, 38.10, 67.40, 114.46, 120.58,
128.04, 128.59, 129.42, 132.99, 136.96, 158.94, 200.02.

FTIR (KBr): 3069, 2944, 2876, 1686, 1601, 1499, 1258, 1032, 735 cm".

HRMS: 254.1307 calculated for C ”H 1 302, found 254.1319.

UV-VIS: €366 (cyclohexane) = 4.5 Lmol"cm"; 8366 (benzene) = 4.0 Lmol'lcm".

Melting Point: 69.5-70.5°C (1n. 69.0°C'°5 ); white crystals.

79

The following compounds were prepared according to the representative procedure

above.

6-Phenoxy-I -phenylhexan-1 -one (Bz-S-OPh)

1H NMR (CDC13, 300 MHz): 6 (ppm) 1.50-1.65 (q, J = 6.6 Hz, 2H), 1.77-1.90
(m, 4H), 3.01 (t, J = 7.2 Hz, 2H), 3.97 (t, J = 6.4 Hz, 2H), 6.89 (d, J = 7.7 Hz, 2H), 6.93
(t, J = 7.4 Hz, 1H), 7.23-7.31 (m, 2H), 7.42-7.50 (m, 2H), 7.56 (t, J = 7.3 Hz, 1H), 7.96
(t, J = 7.0 Hz, 2H).

13C NMR (CDC13, 75 MHz): 6 (ppm) 24.01, 25.87, 29.19, 38.45, 67.54, 114.46,
120.51, 128.03, 128.57, 129.41, 132.95, 137.00, 159.01, 200.00.

FTIR (KBr): 3069, 2942, 2870, 1678, 1599, 1498, 1475, 1244, 1197, 752 cm".

HRMS: 268.1463 calculated for C 18H2002, found 268.1460.

UV-VIS: £366 (cyclohexane) = 4.8 Lmol'lcm'.

Melting Point: 52.0-53.0°C (lit. 53.5--54.5°c'°6 ); white crystals.

8-Phenoxy-I-phenyloctan-1 -one (Bz-7-OPh)

‘H NMR (coc13, 300 MHz): 8 (ppm) 1.35-1.57 (m, 6H), 1.68-1.88 (m, 4H),
2.97 (t, J = 7.4 Hz, 2H), 3.95 (t, J = 6.5 Hz, 2H), 6.89 (d, J = 7.7 Hz, 2H), 6.92 (t, J = 7.3
Hz, 1H), 7.24-7.32 (m, 2H), 7.41-7.50 (m, 2H), 7.55 (t, J = 7.4 Hz, 1H), 7.96 (d, J = 7.1

Hz, 2H).

80

13C NMR (CDC13, 75 MHz): 5 (ppm) 24.25, 25.95, 29.24 (large peak), 29.28,
38.57, 67.76, 114.46, 120.45, 128.05, 128.56, 129.40, 132.90, 137.05, 159.07, 200.50.

FTIR (KBr): 3068, 2936, 2865, 1686, 1601, 1498, 1493, 1240, 1039, 748 cm".

HRMS: 296.1776 calculated for C20H24Oz, found 296.1772.

UV-VIS: £366 (cyclohexane) = 5.0 Lmol"cm"; £366 (benzene) = 4.4 Lmol’lcm".

Melting Point: 44.5-45.0°C; white crystals.

IZ-Phenoxy-l-phenyldodecan-1-one (Bz-ll-O-Ph):
The final product was recrystallized three times from hexane/ethyl acetate mixture (7:3).

‘H NMR(CDC13, 300 MHz): 8 (ppm) 1.25-1.50 (m, 14H), 1.67-1.85 (m, 4H),
2.96 (t, J = 7.1 Hz, 2H), 3.95 (t, J = 6.6 Hz, 2H), 6.90 (d, J = 7.7 Hz, 2H), 6.92 (t, J = 7.4
Hz, 1H), 7.21-7.32 (m, 2H), 7.42-7.50 (m, 2H), 7.55 (t, J = 7.6 Hz, 1H), 7.96 (d, J = 7.1
Hz, 2H).

13C NMR (CDC13, 75 MHz): 8 (Ppm) 24.38, 26.07, 29.30, 29.39 (large peak),
29.44, 29.48, 29.55, 38.64, 67.86, 114.48, 120.43, 128.07, 128.55, 129.51, 132.86,
137.09, 159.12, 200.63.

FTIR (KBr): 2912, 2849, 1682, 1475, 1250, 1028, 750, 691 cm".

HRMS: 352.2402 calculated for C24H3202, found 352.2413.

UV-VIS: 8366 (benzene) = 4.5 Lmol’lcm".

Melting Point: 42.5-43.5°C; white crystals.

81

6-Phenoxy- I -(p-methylphenyl)hexan- 1 -one (MeBz-S-OPh)

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.50-1.64 (q, J = 7.2 Hz, 2H), 1.70-1.90
(m, 4H), 2.39 (s, 3H), 2.96 (t, J = 7.2 Hz, 2H), 3.95 (t, J = 6.6 Hz, 2H), 6.83—6.95 (m,
3H), 7.21-7.30 (m, 4H), 7.85 (d, J = 8.1 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (Ppm) 21.61, 24.11, 25.87, 29.18, 38.33, 67.54.
114.43, 120.49, 128.15, 129.23, 129.38, 134.44, 143.68, 158.99, 199.93.

FTIR (KBr): 2945, 2872, 1674, 1603, 1498, 1476, 1304, 1248, 1182, 1010, 754,
690 cm".

HRMS: 282.1620 calculated for C|9H2202, found 283.1694 (+FAB, MH+).

UV-VIS: £366 (cyclohexane) = 4.9 Lmol"cm"; £366 (benzene) = 4.0 Lmol'lcm'l.

Melting Point: 49.0-50.0°C; white crystals.

6-(2-Naphthyloxy)- l-phenylhexan- I -one (Bz-S-ONp)

‘H NMR (CDC13, 300 MHz): 8 (ppm) 1.55-1.70 (q, J = 7.1 Hz, 2H), 1.78-1.99
(m, 4H), 3.03 (t, J = 7.4 Hz, 2H), 4.09 (t, J = 6.3 Hz, 2H), 7.10-7.17 (m, 2H), 7.28-7.36
(m, 1H), 7.38-7.49 (m, 3H), 7.56 (t, J = 7.1 Hz, 1H), 7.69-7.79 (m, 3H), 7.97 (d, J = 7.0
Hz, 2H).

13C NMR (CDC13, 75 MHz): 8 (ppm) 24.02, 25.93, 29.15, 38.46, 67.69, 106.53,
118.97, 123.48, 126.29, 126.70, 127.62, 128.04, 128.58, 128.88, 129.32, 132.96, 134.58,
137.00, 156.99, 200.25.

FTIR (KBr): 2932, 1684, 1628, 1601, 1390, 1258, 1217, 1183, 1047, 839,754,

690 cm".

82

HRMS: 318.1620 calculated for szszOz, found 318.1618.
UV-VIS: 8366 (cyclohexane) = 5.0 Lmol"cm"; £366 (benzene) = 4.2 Lmol"cm".

Melting Point: 57.0-58.0°C; white crystals.

7-(2-Naphthyloxy)-1 -phenylheptan- I -one (Bz-6-ONp)

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.45-1.65 (m, 4H), 1.75-1.97 (m, 4H),
3.00 (t, J = 7.4 Hz, 2H), 4.08 (t, J = 6.5 Hz, 2H), 7.11-7.18 (m, 2H), 7.29-7.37 (m, 1H),
7.39-7.50 (m, 3H), 7.56 (t, J = 7.1 Hz, 1H), 7.69-7.79 (m, 3H). 7.97 (d, J = 7.0 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 24.28, 26.07, 29.16 (large peak), 38.51,
67.87, 106.57, 119.05, 123.51, 126.33, 126.73, 127.67, 128.09, 128.61, 128.91, 129.35,
132.97, 134.65, 137.13, 157.10, 200.45.

FTIR (KBr): 2938, 2867, 1684, 1630, 1599, 1468, 1446, 1390, 1262, 1221,
1036, 837, 739, 689 cm“.

HRMS: 332.1776 calculated for C23H24Oz, found 332.1779.

UV-VIS: e366 (cyclohexane) = 5.1 Lmol'lcm'l; e366 (benzene) = 4.3 Lmol'lcm".

Melting Point: 84.0-85.0°C; white crystals.

8-(2-Naphthyloxy)- I -phenyloctan- I -one (Bz-7-0Np)
1H NMR (CDC13, 300 MHz): 6 (Ppm) 1.38-1.60 (m, 6H), 1.70-1.92 (m, 4H),
2.98 (t, J = 7.23 Hz, 2H), 4.07 (t, J = 6.5 Hz, 2H), 7.15—7.19 (m, 2H), 7.24-7.28 (m, 1H),

7.39-7.50 (m, 3H), 7.56 (t, J = 7.4 Hz, 1H), 7.69—7.78 (m, 3H), 7.96 (d, J = 7.0 Hz, 2H).

83

13C NMR (CDC13, 75 MHz): 5 (ppm) 24.25, 26.00, 29.20, 29.25, 29.29, 38.56,
67.91, 106.51, 119.02, 123.47, 126.28, 126.68, 127.62, 128.06, 128.57, 128.87, 129.30,
132.90, 134.60, 137.06, 157.07, 200.50.

EUR (KBr): 2934, 2865, 1687, 1633, 1599, 1512, 1468, 1348, 1264, 1223,
1127, 1036, 857, 806, 742, 688 cm".

HRMS: 346.1933 calculated for C24H26Oz, found 346.1931.

UV-VIS: 8356 (cyclohexane) = 5.0 Lmol'lcm"; 8366 (benzene) = 4.4 Lmol'lcm'l.

Melting Point: 44.0-45.0°C; white crystals.

12-(2-Naphthyloxy)- I -phenyldodecan- I -one (Bz-l l-ONp)
The final product was recrystallized from hexane/ethyl acetate mixture (7:3).

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.25-1.57 (m, 14H), 1.68-1.90 (m, 4H),
2.96 (t, J = 7.1 Hz, 2H), 4.07 (t, J = 6.6 Hz, 2H), 7.12-7.19 (m, 2H), 7.28-7.35 (m, 1H),
7.39-7.49 (m, 3H), 7.55 (t, J = 6.9 Hz, 1H), 7.69-7.78 (m, 3H), 7.96 (d, J = 7.0 Hz, 2H).

13C NMR (CDC13, 75 MHz): 8 (ppm) 24.36, 26.10, 29.24, 29.36, 29.39, 29.47
(large peak), 29.54 (large peak), 38.62, 67.98, 106.49, 119.02, 123.42, 126.25, 126.67,
127.61, 128.04, 128.53, 128.84, 129.27, 132.85, 134.60, 137.07, 157.06, 200.60.

EUR (KBr): 2914, 2869, 1682, 1631, 1514, 1346, 1261, 1226, 1126, 856, 806,
742, 688 cm".

HRMS: 402.2559 calculated for C23H3402, found 402.2552.

UV-VIS: 8366 (benzene) = 4.5 Lmol'lcm‘l.

Melting Point: 64.0-65.0°C; white crystals.

84

15-(2-Naphthyloxy)- l -phenylpentadecan - 1 -one (Bz-14-ONp)
The final product was recrystallized from hexane/ethyl acetate mixture (7:3).

lH NMR(CDC13, 300 MHz): 8 (ppm) 125-1.54 (m, 20H), 1.66-1.92 (m, 4H),
2.94 (t, J = 7.2 Hz, 2H), 4.06 (t, J = 6.6 Hz, 2H), 7.10-7.17 (m, 2H), 7.27-7.35 (m, 1H),
7.37-7.48 (m, 3H), 7.50-7.57 (m, 1H), 7.68-7.78 (m, 3H), 7.95 (d, J = 6.9 Hz, 2H).

13C NMR (coc13, 75 MHz): 8 (ppm) 24.34, 26.09, 29.23, 29.35, 29.46 (large
peak), 29.55 (large peak), 29.59 (large peak), 38.62, 67.98, 106.49, 119.02, 123.40,
126.24, 126.65, 127.60, 128.04, 128.52, 128.82, 129.26, 132.83, 134.59, 137.07, 157.09,
200.60.

FTIR (KBr): 2917, 2849, 1684, 1628, 1601, 1464, 1262, 1221, 1026, 841, 740,
689 cm".

HRMS: 444.3028 calculated for CHI-14002, found 444.3022.

UV-VIS: €366 (benzene) = 4.6 Lmol'lcm'l.

Melting Point: 97.5-99.0°C; white crystals.

6-(4-Biphenyloxy)-I-phenylhexan-1 -one (Bz-S-O4Bp)
1H NMR (CDC13, 300 MHz): 5 (ppm) 1.50-1.69 (q, J = 7.1 Hz, 2H), l.75-1.90
(m, 4H), 3.01 (t, J = 6.9 Hz, 2H), 4.00 (t, J = 6.3 Hz, 2H), 6.95 (d, J = 8.7 Hz, 2H), 7.22-

7.59 (m, 10H), 7.96 (d, J = 7.5 Hz, 2H).

85

13C NMR (CDC13, 75 MHz): 8 (ppm) 23.96, 25.85, 29.15, 38.43, 67.73, 114.71,
126.57, 126.67, 128.01, 128.07, 128.56, 128.66, 132.94, 133.95, 136.95, 140.80, 158.57,
200.23.

EUR (KBr): 3034, 2936, 2862, 1674, 1606, 1524, 1489, 1471, 1292, 1255,
1199, 1176, 974, 833, 761, 686 cm".

HRMS: 344.1776 calculated for CzaHzaOz, found 344.1776.

UV-VIS: 8366 (cyclohexane) = 4.9 Lmol'lcm'l; e366 (benzene) = 4.3 Lmol'lcm'l.

Melting Point: 70.0—71.5°C; white crystals.

7-(4-Biphenyloxy)- 1 -phenylheptan- I -one (Bz-6-O4Bp)

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.40-1.62 (m, 4H), 1.71-1.89 (m, 4H),
2.98 (t, J = 7.2 Hz, 2H), 3.99 (t, J = 6.3 Hz, 2H), 6.96 (d, J = 8.7 Hz, 2H), 7.22-7.60 (m,
10H), 7.96 (d, J = 7.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 8 (ppm) 24.17, 25.93, 29.04, 29.10, 38.42, 67.85,
114.69, 126.55, 126.65, 127.99, 128.09, 128.62, 128.65, 132.87, 133.50, 136.97, 140.81,
158.61, 200.34.

FTIR (KBr): 2932, 2867, 1682, 1608, 1524, 1489, 1448, 1276, 1258, 1201,
1041, 831,758,689 cm".

HRMS: 358.1933 calculated for C25H26Oz, found 358.1930.

UV-VIS: e366 (cyclohexane) = 4.9 Lmol'lcm'l; £366 (benzene) = 4.4 Lmol'lcm'l.

Melting Point: 124.0-125.0°C; white crystals.

86

8-(4-Biphenyloxy)- I -phenyloctan- 1 -one (Bz-7-O4Bp)

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.36-1.59 (m, 6H), 1.70-1.88 (m, 4H),
2.97 (t, J = 7.2 Hz, 2H), 3.99 (t, J = 6.3 Hz, 2H), 6.96 (d, J = 8.7 Hz, 2H), 7.23-7.58 (m,
10H), 7.96 (d, J = 7.5 Hz, 2H).

13’C NMR (CDC13, 75 MHz): 5 (ppm) 24.21, 25.89, 29.20 (large peak), 29.23,
38.50, 67.93, 114.70, 126.55, 126.66, 128.02, 128.05, 128.53, 128.66, 132.86, 133.47,

136.99, 140.82, 158.63, 200.47.

FTIR (KBr): 2924, 2849, 1680, 1607, 1523, 1489, 1449, 1252, 1163, 1076, 841,

762, 687 cm".
HRMS: 372.2090 calculated for C26H2302, found 372.2075.

UV-VIS: €366 (cyclohexane) = 4.9 Lmol"cm"; €366 (benzene) = 4.5 Lmol'lcm'l.

Melting Point: 72.5-73.0°C; white crystals.

12-(4-Biphenyloxy)- 1 -phenyldodecan- I -one (Bz-l l-O4Bp)
The final product was recrystallized three times from hexane/ethyl acetate mixture (7:3).
‘H NMR (CDC13, 300 MHz): 8 (ppm) 1.20-1.57 (m, 14H), 1.70-1.90 (m, 4H),
2.99 (t, J = 7.4 Hz, 2H), 4.02 (t, J = 6.5 Hz, 2H), 6.99 (d, J = 8.8 Hz, 2H), 7.25-7.62 (m,
10H), 7.98 (d, J = 7.5 Hz, 2H).
13C NMR (CDC13, 75 MHz): 5 (ppm) 24.36, 26.05, 29.29, 29.37, 29.47 (large

peak), 29.54 (large peak), 29.72, 38.62, 68.05, 114.74, 126.57, 126.69, 128.04, 128.08,

128.21, 128.54, 128.68, 132.85, 133.49, 137.07, 140.88, 158.70, 200.61.

87

FTIR (KBr): 2912, 2849, 1680, 1606, 1489, 1446, 1286, 1253, 1201, 1024, 839,

758, 689 cm".
HRMS: 428.2715 calculated for C30H3602, found 428.2716.
UV-VIS: 8366 (benzene) = 4.6 Lmol"cm".

Melting Point: 80.5-81.0°C; white crystals.

15-(4-Biphenyloxy)- I -phenylpentadecan-1-one (Bz-l4-O4Bp)
The final product was recrystallized three times from hexane/ethyl acetate mixture (6:4).
1H NMR (CDC13, 300 MHz): 5 (ppm) 1.20-1.53 (m, 20H), 1.65-1.84 (m, 4H),
2.98 (t, J = 7.2 Hz, 2H), 4.01 (t, J = 6.6 Hz, 2H), 6.98 (d, J = 9.0 Hz, 2H), 7.23-7.60 (m,
10H), 7.98 (d, J = 7.2 Hz, 2H).
13'C NMR (CDCI3, 75 MHz): 8 (ppm) 24.37, 26.05, 29.29, 29.38 (large peak),
29.50, 29.57, 29.60 (large peak), 38.62, 68.06, 114.72, 126.56, 126.68, 128.03, 128.08,
128.52, 128.67, 132.84, 133.48, 137.06, 140.86, 158.69, 200.62.
EUR (KBr): 2916, 2849, 1684, 1608, 1494, 1257, 1201, 1030, 831, 758, 688
cm' .
HRMS: 470.3185 calculated for C33H4202, found 470.3181.
UV-VIS: e366 (benzene) = 4.5 Lmol’lcm'l.

Melting Point: 120.5-121.0°C; white crystals.

88

6-(2-Biphenyloxy)-1 -phenylhexan-1 -one (Bz-S-OZBp)

lH NMR(CDC13, 300 MHz): 6 (ppm) 1.40-152 (q, J = 7.1 Hz, 2H), 1.67-1.81
(m, 4H), 2.91 (t, J = 6.9 Hz, 2H), 3.96 (t, J = 6.3 Hz, 2H), 6.94-7.04 (m, 2H), 7.23-7.58
(m, 10H), 7.93 (d, J = 8.1 Hz, 2H).

13C NMR (CDCl3, 75 MHz): 5 (ppm) 23.83, 25.81, 29.00, 38.41, 68.14, 112.56,

120.80, 126.70, 127.76, 128.01, 128.56 (large peak), 129.59, 130.81, 130.91, 132.92,

136.96, 138.57, 155.90, 200.23.
FTIR (KBr): 3059, 2940, 1684, 1597, 1504, 1483, 1433, 1261, 1231, 1122,
1008, 752, 698 cm".
HRMS: 344.1776 calculated for C24H2402, found 345.1856 (+FAB, MH+).
UV-VIS: €366 (cyclohexane) = 4.8 Lmol"cm".

Colorless liquid.

7-(2-Biphenyloxy)-1 -phenylheptan-1 -one (Bz-6-02Bp)

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.25-1.50 (m, 4H), 1.62-1.80 (m, 4H),
2.91 (t, J = 7.5 Hz, 2H), 3.95 (t, J = 6.3 Hz, 2H), 6.94-7.04 (m, 2H), 7.22-7.58 (m, 10H),
7.93 (d, J = 8.7 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 24.16, 25.94, 28.91, 28.97, 38.41, 68.28,
112.50, 120.74, 126.69, 127.75, 128.02, 128.52 (large peak), 129.57, 130.81, 130.91,
132.88, 137.02, 138.58, 155.94, 200.31.

FTIR (KBr): 2941, 1686, 1595, 1505, 1474, 1435, 1265, 1235, 1194, 1122.

1034, 966, 750, 702 cm".

89

HRMS: 358.1933 calculated for C25H2602, found 358.1922.
UV-VIS: €366 (cyclohexane) = 4.8 Lmol"cm"; e366 (benzene) = 4.3 Lmol'lcm’l.

Melting Point: 50.5-51.0°C; white crystals.

8 -( 2 -Biphenyloxy )- I -phenyloctan-1 -one (Bz-7-02Bp)

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.23-1.50 (m, 6H), 1.62-1.80 (m, 4H),
2.94 (t, J = 7.5 Hz, 2H), 3.95 (t, J = 6.6 Hz, 2H), 6.95-7.05 (m, 2H), 7.24-7.59 (m, 10H),
7.96 (d, J = 7.9 Hz, 2H).

13C NMR (CDC13, 75 MHz): 6 (ppm) 24.14, 25.87, 29.03 (large peak), 29.18,
38.47, 68.29, 112.46, 120.67, 126.65, 127.72, 127.97, 128.49 (large peak), 129.54,
130.77, 130.84, 132.81, 136.99, 138.55, 155.92, 200.39.

FTIR (KBr): 2934, 1686, 1597, 1483, 1435, 1261, 1122, 754, 698 cm".

HRMS: 372.2089 calculated for ngHngz, found 373.2167 (+FAB, MH").

UV-VIS: £366 (cyclohexane) = 4.8 Lmol"cm".

Colorless liquid.

I 2-(2-Biphenyloxy)- I -phenyldodecan- 1 -one (Bz-ll-O2Bp)
The final product was recrystallized from hexane/ethyl acetate mixture (7:3).

1H NMR (CDC13, 300 MHz): 6 (ppm) 1.18-1.46 (m, 14H), 1.60-1.84 (m, 4H),
2.96 (t, J = 7.5 Hz, 2H), 3.95 (t, J = 6.6 Hz, 2H), 6.94-7.04 (m, 2H), 7.24-7 .58 (m, 10H),

7.96 (d, J = 7.2 Hz, 2H).

90

13C NMR (CDC13, 75 MHz): 6 (ppm) 24.35, 26.03, 29.13, 29.22, 29.36, 29.46
(large peak), 29.51, 38.61, 68.36, 112.44, 120.67, 126.68, 127.75, 128.03, 128.51 (large
peak), 129.57, 130.80 (large peak), 132.84 , 137.06, 138.59, 155.99, 200.57.

FTIR (KBr): 2921, 1696, 1595, 1473, 1437, 1265, 1232, 1205, 1120, 1010, 750,
702 cm".

HRMS: 428.2715 calculated for C30H3602, found 428.2711.

UV-VIS: €366 (benzene) = 4.5 Lmol'lcm'i.

Melting Point: 41 .0-42.0°C; white crystals.

15-(2-Biphenyloxy)- 1 -phenylpentadecan- I -one (Bz-l4-02Bp)
The final product was recrystallized from hexane/ethyl acetate mixture (6:4).

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.19-1.42 (m, 20H), 1.62-1.80 (m, 4H),
2.94 (t, J = 7.2 Hz, 2H), 3.93 (t, J = 6.6 Hz, 2H), 6.93-7.03 (m, 2H), 7.24-7.57 (m, 10H),
7.94 (d, J = 7.2 Hz, 2H).

”C NMR (CDC13, 75 MHz): 6 (ppm) 24.37. 26.04, 29.14, 29.24, 29.38, 29.54
(large peak), 29.63 (large peak), 38.63, 68.38, 112.45, 120.67, 126.68, 127.77, 128.03,
128.40, 128.53, 129.58, 130.81 (large peak), 132.83, 138.75, 139.08, 156.00, 200.60.

FTIR (KBr): 2920, 2851, 1684, 1599, 1469, 1433, 1264, 1238, 1124, 748, 729,
690 cm".

HRMS: 470.3185 calculated for C33H4202, found 470.3194.

UV-VIS: e366 (benzene) = 4.6 Lmol"cm".

Melting Point: 47.0-48.5°C; white crystals.

91

7-( 3 -Biphenyloxy )-1 -phenylheptan-1-one (Bz-6-OBBp)

‘H NMR (CDC13, 300 MHz): 6 (ppm) ) 1.40-1.62 (m, 4H), 1.70-1.90 (m, 4H),
2.98 (t, J = 7.2 Hz, 2H), 4.02 (t, J = 6.3 Hz, 2H), 6.88 (d, J = 8.1 Hz, 1H), 7.10-7.62 (m,
11H), 7.96 (d, J = 8.1 Hz, 2H).

l3C NMR(CDC13, 75 MHz): 6 (ppm) 24.18, 25.94, 29.05, 29.15, 38.42, 67.81,

113.17, 113.46, 119.46, 127.13, 127.32, 127.99, 128.52, 128.65, 129.67, 132.86, 136.99,

141.08, 142.64, 159.41, 200.33.
FTIR (KBr): 2939, 1682, 1597, 1485, 1300, 1219, 758, 723, 691 cm".
HRMS: 358.1933 calculated for C25H2602, found 358.1926.
UV-VIS (cyclohexane): 8366 = 4.9 Lmol'lcm'l.

Melting Point: 45.0-46.0°C; white crystals.

8-( 3 -Biphenyloxy )-1 -phenyloctan-I -one (Bz-7-O3Bp)

1H NMR (CDC13, 300 MHz): 6 (ppm) 1.35-1.58 (m, 6H), 1.68-1.88 (m, 4H),
2.96 (t, J = 7.5 Hz, 2H), 4.00 (t, J = 6.3 Hz, 2H), 6.87 (d, J = 8.1 Hz, 1H), 7.10-7.61 (m,
11H), 7.95 (d, J = 6.9 Hz, 2H).

13C NMR (CDC13, 75 MHz): 6 (ppm) 24.22, 25.92, 29.16, 29.21, 29.24, 38.52,
67.90, 113.20, 113.47, 119.44, 127.15, 127.31, 128.01, 128.53, 128.66, 129.66, 132.85.
137.02, 141.11, 142.65, 159.44, 200.44.

FTIR (KBr): 2936, 1688, 1601, 1473, 1302, 1213, 1033, 966,756,690 cm".

HRMS: 372.2090 calculated for C26H2302, found 373.2166.

92

UV-VIS (cyclohexane): 8366 = 4.8 Lmol"cm".

Melting Point: 39.0-40.0°C; white crystals.

15-(3-Biphenyloxy)- I -phenylpentadecan- I -one (Bz-l4-O3Bp)
The final product was recrystallized from hexane/ethyl acetate mixture (7:3).

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.18-1.45 (m, 20H), 1.65-1.85 (m, 4H),
2.94 (t, J = 7.5 Hz, 2H), 4.00 (t, J = 6.6 Hz, 2H), 6.87 (d, J = 8.4 Hz, 1H), 7.10-7.60 (m,
11H), 7.94 (d, J = 7.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 6 (ppm) 24.37, 26.07, 29.27 (large peak), 29.32,
29.39 (large peak), 29.50, 29.62 (large peak), 38.62, 68.03, 113.22, 113.50, 119.43,
126.67, 127.16, 127.32, 128.03, 128.52, 128.67, 129.66, 132.67, 137.08, 142.67, 159.48,
200.61.

FTIR (KBr): 2915, 2851, 1686, 1595, 1468, 1217, 760, 691 cm'l.

HRMS: 470.3185 calculated for C33H4202, found 470.3171.

UV-VIS (benzene): 8366 = 4.6 Lmol'lcm".

Melting Point: 62.0-63.0°C; white crystals.

6-( 2 -Naphthyloxy )- 1 -(p-methylphenyl)hexan- I -one (MeBz-S-ONp)
1H NMR (CDC13, 300 MHz): 6 (ppm) 1.57-1.66 (q, J = 7.2 Hz, 2H), 1.78-1.96
(m, 4H), 2.40 (s, 3H), 2.99 (t, J = 7.2 Hz, 2H), 4.08 (t, J = 6.5 Hz, 2H), 7.10-7.16 (m,

2H), 7.22-7.46 (m, 4H), 7.66-7.78 (m, 3H), 7.86 (d, J = 8.2 Hz, 2H).

93

13C NMR (CDC13, 75 MHz): 5 (ppm) 21.59, 24.11, 25.91, 29.12, 38.31, 67.67,
106.51, 118.94, 123.44, 126.25, 126.67, 127.58, 128.13, 128.85, 129.22, 129.28, 134.50,
134.56, 143.65, 156.97, 199.89.

FTIR (KBr): 2948, 1674, 1629, 1599, 1468, 1388, 1259, 1182, 1005, 833, 812,
744 cm'l.

HRMS: 332.1776 calculated for C23H2402, found 332.1796.

UV-VIS: £366 (cyclohexane) = 4.8 Lmol'lcm".

Melting Point: 77.0-78.0°C; white crystals.

7-(2-Naphthyloxy)-1 -(p-methylphenyl)heptan- I -one (MeBz-6-0Np)

‘H NMR (CDC13, 300 MHz): 6 (ppm) 1.42-1.62 (m, 4H), 1.72-1.93 (m, 4H),
2.41 (s, 3H), 2.97 (t, J = 7.2 Hz, 2H), 4.08 (t, J = 6.5 Hz, 2H), 7.10-7.16 (m, 2H), 7.22-
7.46 (m, 4H), 7.68-7.75 (m, 3H), 7.87 (d, J = 8.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 21.62, 24.36, 26.02, 29.13, 38.36, 67.83,
105.51, 119.00, 123.45, 126.27, 126.68, 127.24, 127.62, 128.18, 128.42, 128.86, 129.24,
129.30, 134.60 (large peak), 143.65, 157.05, 200.10.

FTIR (KBr): 3057, 2939, 2867, 1680, 1628, 1599, 1466, 1390, 1262, 1219,
1184, 1037, 839,793,741 cm".

HRMS: 346. 1933 calculated for C24H2602, found 346.1942.

UV-VIS: e366 (cyclohexane) = 4.9 Lmol"cm"; €366 (benzene) = 4.3 Lmol"cm".

Melting Point: 88.5-90.0°C; white crystals.

94

8-(2-Naphthyloxy)- 1 -(p-methylphenyl)octan- I -one (MeBz-7-ONp)

1H NMR(CDC13, 300 MHz): 8 (ppm) ) 1.40-1.58 (m, 6H), 1.70-1.90 (m, 4H),
2.41 (s, 3H), 2.95 (t, J = 7.2 Hz, 2H), 4.07 (t, J = 6.6 Hz, 2H), 7.1 1-7.17 (m, 2H), 7.22-
7.46 (m, 4H), 7.69-7.78 (m, 3H), 7.87 (d, J = 8.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 21.61, 24.36, 25.98, 29.18, 29.64, 29.30.
38.44, 67.89, 106.47, 119.01, 123.43, 126.26, 126.67, 127.61, 128.17, 128.82, 129.22,
129.28, 134.59 (large peak), 143.62, 157.05, 200.22.

FTIR (KBr): 3056, 2930, 2855, 1674, 1630, 1601, 1466, 1388, 1259, 1217,

1182, 1118, 831, 806, 744 cm".
HRMS: 360.2089 calculated for C25H2302, found 360.2099.
UV-VIS: 8366 (benzene) = 4.4 Lmol'lcm'l.

Melting Point: 48.5-49.0°C; white crystals.

12-(2-Naphthyloxy)-I-(p-methylphenyl)dodecan-l-one (MeBz-ll-ONp)

1H NMR (CDC13, 300 MHz): 6 (ppm) ) 125-1.55 (m, 14H), 1.65-1.90 (m, 4H),
2.40 (s, 3H), 2.93 (t, J = 7.4 Hz, 2H), 4.07 (t, J = 6.6 Hz, 2H), 7.10-7.17 (m, 2H), 7.22-
7.46 (m, 4H), 7.69-7.78 (m, 3H), 7.86 (d, J = 8.3 Hz, 2H).

l°C NMR (CDC13, 75 MHz): 5 (ppm) 21.60, 24.48, 26.09, 29.24, 29.38, 29.47
(large peak), 29.54 (large peak), 38.52, 67.98, 106.49, 119.02, 123.41, 126.24, 126.66,
127.60, 128.17, 128.83, 129.20 (large peak), 129.26, 134.60, 143.56, 157.08, 200.30.

FTIR (KBr): 2914, 2849, 1678, 1599, 1466, 1263, 1226, 1180, 854, 808, 779,

743 cm".

95

HRMS: 416.2715 calculated for C29H3602, found 416.2703.
UV-VIS: €366 (benzene) = 4.5 Lmol"cm".

Melting Point: 70.0-71.0°C; white crystals.

C. Synthesis of wlodoalkyl Aryl Ketones from (o-Chloroalkyl Nitriles
(o—Iodoalkyl aryl ketones Ar-CO-(CH2)x-l (Ar = phenyl, 4-methylphenyl; x = 3, 4)

were prepared in two steps following the route given below:

 

Br 0
1. Mg, E120
g (CH2),-c1
2. NC-(CH2)x-Cl R
R

3. acetone, H20, H3O+, heat

NaI, acetone, reflux

O

(CH2)x-I

R

Scheme 13. Synthesis of 0)—Iodoalkanoary1 Ketones (R = H, Me)

96

4-Chloro-l-phenylbutan-l-one

In a 250 mL three necked round bottom flask equipped with a condenser and
purged with argon a solution of the 3-chlorobutyronitrile (8.0 g, 0.1 mol) in diethyl ether
(10 mL) was added dropwise to a solution of phenylmagnesium bromide prepared from
phenyl bromide (16.5 g, 0.105 mol) and magnesium (2.7 g, 0.1 1 mol) in diethyl ether (60
mL) at 5°C. After all the nitrile had been added, the mixture was stirred at 25°C for 2 hrs.
and it was poured into a mixture of distilled water and ice (about 50 mL). The mixture
was slowly neutralized by 10% hydrochloric acid solution and heated and stirred at 35°C
for 2 hrs. The product was extracted with diethyl ether (3x 50 mL), and the combined
ether layer was washed with saturated sodium hydrogen carbonate solution, distilled
water, and dried over MgSO4. The solvent was evaporated to yield the crude product
(75%) which was used in the next step without further purification.
4-Chloro-I-phenylbutan-1-one: 1H NMR (CDC13): 5 (ppm) 2.2 (tt, 2H), 3.1 (t, 2H), 3.7

(t, 2H), 7.4-7.9 (m, 5H).

4-Iodo-1-phenylhutan-l-one

The mixture of the 4-chloro-1-phenylbutan-1-one (12.8 g, 0.07 mol) and sodium
iodide (52.5 g, 0.35 mol) in dry acetone (600 mL) was refluxed for 24 hrs. in dark. The
solvent was evaporated and distilled water (300 mL) was added. The product was
extracted with diethyl ether (200 mL, 2x 50 mL), the combined ether layer was washed

with saturated sodium thiosulfate solution and distilled water, and dried over MgSOa.

97

The solvent was evaporated and the product was recrystallized from hexane/ethyl acetate
mixture (9:1). The yield was 90%.
4—Iodo-1-phenylbutan-I-one: 1H NMR (CDC13): 5 (ppm) 2.2 (tt, 2H), 3.1 (t, 2H), 3.3 (t,

2H), 7.4-7.9 (m, 5H).

D. Synthesis of 0)-Aryloxyalkyl Aryl Ketones
0)-Aryloxyalkyl aryl ketones Ar-CO-(CH2)x-OAr’ (Ar = phenyl, 4-methylphenyl;
Ar’ = phenyl, 2-naphthyl, 2/3/4-biphenyl, x = 3-4) were prepared in three steps according

to the Scheme 13.

Ethylene glycol ketal of 4-iodo-l-phenylbutan-1-one

The mixture of the 4-iodo-1-phenylbutan-1-one (18.4g, 0.067 mol), p-
toluenesulfonic acid (0.03 g), and ethyleneglycol (14.6 g, 0.23 mol) in benzene (60 mL)
was refluxed for 24 hrs. using a modified Dean-Stark trap and molecular sieve (4A). The
reaction was completed when the solvent over the sieve was clear. The solution was then
washed with saturated sodium hydrogen carbonate solution, distilled water, and dried
over MgSOa. The solvent was evaporated and the product (80% yield) was used in the

next step without further purification.

Ethylene glycol ketal of 4—iod0-l-phenylbutan-l-one: 1H NMR (CDC13): 5 (ppm) 1.6-1.9

(m, 4H), 3.2 (t, 2H), 3.8 (t, 2H), 4.0 (t, 2H), 7.4-8.0 (m, 5H).

98

Ethylene glycol ketal of 4-phenoxy-l-phenylbutan-l-one

A solution of ethylene glycol ketal of the 4-iodo-l-phenylbutan-l-one (16.9 g,
0.053 mol) and sodium phenolate, prepared from a phenol (50 g, 0.053 mol) and sodium
(1.3 g, 0.058 mol) in absolute methanol, in dimethylformamide (200 mL) was stirred at
50°C for 30 hrs. Distilled water was added (200 mL) and the product was extracted with
diethyl ether (3x 100 mL). The combined ether layer was washed with saturated sodium
chloride solution, distilled water, and dried over MgSO4. The solvent was evaporated
and the crude product (85%) was used in the next step without further purification.
Ethylene glycol ketal of 4-phenoxy-I-phenylbutan-I-one: 1H NMR (CDC13): 5 (ppm)

1.3-1.9 (m, 4H), 3.7 (t, 2H), 3.8-4.1 (m, 4H), 6.9-8.0 (m, 5H).

4-Phenoxy-l-phenylbutan-1-one

A solution of ethylene glycol ketal of the 4-phenoxy-l-phenylbutan-l-one (12.8
g, 0.047 mol) and a catalytic amount of 10% hydrochloric acid in acetone (300 mL) was
stirred at 40°C for 24 hrs. Distilled water (300 mL) was added and the product was
extracted with diethyl ether (3x 100 mL). The combined ether layer was washed with
saturated sodium hydrogen carbonate solution, distilled water, and dried over MgSO4.
The solvent was evaporated and the crude product (75-80%) was purified by flash

chromatography and recrystallized from hexane/ethyl acetate mixture (8:2).

99

4 -Phenoxy-I -phenylbutan-1 -one (Bz-3-OPh)

1H NMR (CDC13, 300 MHz): 5 (ppm) 2.25 (tt, J = 6.5, 7.1 Hz, 2H), 3.22 (t, J =
7.1 Hz, 2H), 4.08 (t, J = 6.5 Hz, 2H), 6.91 (d, J = 7.8 Hz, 2H), 6.94 (t, J = 7.4 Hz, 1H),
7.23-7.31 (m, 2H) 7.43-7.49 (m, 2H), 7.57 (t, J = 7.3 Hz, 1H), 7.99 (d, J = 7.0 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 23.79, 34.95, 66.77, 114.45, 120.67,
128.03, 128.59, 129.44, 133.07, 136.90, 158.83, 199.61.

FTIR (KBr): 3069,3042, 2911, 1688, 1601, 1497, 1279, 1036, 743 cm".

HRMS: 240.1 150 calculated for C16H1602, found 240.1 149.

UV-VIS: £366 (cyclohexane) = 3.1 Lmol"cm"; €366 (benzene) = 2.5 Lmol"cm".

Melting Point: 62.5-63.0°C (lit. 63.0°c‘°5) ; white crystals.

The following compounds were prepared according to the representative procedure

above.

4 -Phenoxy- 1-(p-methylphenyl)butan- I -one (MeBz-3-0Ph)

‘H NMR (CDC13, 300 MHz): 6 (ppm) 2.17 (tt, J = 6.0, 7.2 Hz, 2H), 2.34 (s, 3H),
3.11 (t, J = 7.2 Hz, 2H), 4.00 (t, J = 6.0 Hz, 2H), 6.80-6.90 (m, 3H), 7.15-7.25 (m, 4H),
7.85 (d, J = 8.1 Hz, 2H).

13C NMR (CDC13, 75 MHz): 6 (ppm) 21.59, 23.81, 34.78, 66.79, 114.39, 120.60,
128.10, 129.22, 129.39, 134.39, 143.77, 158.80, 199.21.

FTIR (KBr): 2943, 2803, 1674, 1606, 1585, 1486, 1366, 1248, 1172, 1036, 817,

748,688 cm".

100

HRMS: 254.1307 calculated for C ”H.302, found 254.1297.
UV-VIS: €366 (cyclohexane) = 2.9 Lmol"cm"; 8366 (benzene) = 2.3 Lmol’lcm'l.

Melting Point: 58.3-59.0°C; white crystals.

5 -Phenoxy- I -(p-methylphenyl)pentan- I -one (MeBz-4-OPh)

1H NMR (CDC13, 300 MHz): 6 (ppm) 1.80-1.98 (m, 4H), 2.38 (s, 3H), 3.00 (t, J
= 6.6 Hz, 2H), 3.97 (t, J = 6.0 Hz, 2H), 6.82-6.95 (m, 3H), 7.20-7.32 (m, 4H), 7.84 (d, J
= 7.8 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 20.97, 21.59, 28.80, 37.94, 67.41, 114.41,
120.51, 128.11, 129.20, 129.37, 134.44, 143.68, 158.90, 199.64.

FTIR (KBr): 2957, 1678, 1601, 1500, 1464, 1292, 1251, 1178, 1049, 979, 791,

758 cm".
HRMS: 268.1463 calculated for C(3H2002, found 268.1459.
UV-VIS: £366 (cyclohexane) = 4.1 Lmol"cm"; €366 (benzene) = 3.7 Lmol"cm".

Melting Point: 83.0-83.5°C; white crystals.

4 -( 2 -Naphthyloxy )- 1 -phenylbutan-1 -one (Bz-3-0Np)
1H NMR (CDC13, 300 MHz): 5 (ppm) 2.31 (tt, J = 6.0, 7.1 Hz, 2H), 3.25 (t, J =
7.1 Hz), 4.19 (t, J = 6.0 Hz, 2H), 7.11-7.16 (m, 2H), 7.29-7.36 (m, 1H), 7.39-7.50 (m,

3H), 7.56 (t, J = 7.0 Hz, 1H), 7.68-7.78 (m, 3H), 8.00 (d, J = 7.0 Hz, 2H).

101

13C NMR (CDC13, 75 MHz): 6 (ppm) 23.77, 35.00, 66.94, 106.63, 118.84,
123.57, 126.33, 126.73, 127.61, 128.04, 128.60, 128.93, 129.37, 133.09, 134.55, 136.90,
156.80, 199.60.

FTIR (KBr): 3056, 1682, 1630, 1595, 1464, 1275, 1228, 1026, 852, 742 cm".

HRMS: 290.1307 calculated for C20H1302, found 290.1305.

UV-VIS: €366 (cyclohexane) = 3.0 Lmol'lcm'l; e366 (benzene) = 2.4 Lmol'lcm'l.

Melting Point: 64.5-65.5°C; white crystals.

5 -( 2 -Naphthyloxy )-1 -phenylpentan-I -one (Bz-4-ON p)

1H NMR (CDC13, 300 MHz): 6 (ppm) 1.88-2.07 (m, 4H), 3.09 (t, J = 6.9 Hz,
2H), 4.13 (t, J = 5.8 Hz, 2H), 7.07-7.15 (m, 2H), 7.27-7.35 (m, 1H), 7.37-7.50 (m, 3H),
7.56 (t, J = 7.2 Hz, 1H), 7.67-7.78 (m, 3H), 7.97 (d, J = 7.0 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 21.00, 28.80, 38.13, 67.60, 106.56, 118.99,
123.55, 126.35, 126.74, 127.66, 128.08, 128.63, 128.93, 129.37, 133.04, 134.60, 136.99,
156.95, 200.03.

FTIR (KBr): 2928, 1686, 1630, 1.599, 1464, 1258, 1219, 1186, 976, 843, 735
cm' .

HRMS: 304.1463 calculated for ClezoOz, found 304.1471.

UV-VIS: e366 (cyclohexane) = 5.0 Lmol"cm"; £366 (benzene) = 4.0 Lmol'lcm'l.

Melting Point: 94.5-95.0°C; white crystals.

102

4-(4-Biphenyloxy)- 1 -phenylbutan- l-one (Bz-3-O4Bp)

1H NMR (CDC13, 300 MHz): 5 (ppm) 2.27 (tt, J = 6.0, 6.9 Hz, 2H), 3.22 (t, J =
6.9 Hz, 2H), 4.11 (t, J = 6.0 Hz, 2H), 6.97 (d, J = 8.7 Hz, 2H), 7.24-7.60 (m, 10H), 7.98
(d, J = 7.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 6 (ppm) 23.73, 34.88, 66.93, 114.69, 126.60,
126.66, 127.99, 128.09, 128.56, 128.67, 133.05, 133.71, 136.83, 140.73, 158.37, 199.54.

EUR (KBr): 3031, 2942, 1692, 1604, 1522, 1471, 1246, 1201, 1041, 763, 694
cm' .

HRMS: 316.1463 calculated for szHzoOz, found 316.1465.

UV-VIS: €366 (cyclohexane) = 3.0 Lmol"cm"; €366 (benzene) = 2.4 Lmol"cm".

Melting Point: 87.0-88.0°C; white crystals.

5 -( 4 -Biphenyloxy )-1 -phenylpentan-1-one (Bz-4-O4Bp)

lH NMR(CDC13, 300 MHz): 6 (ppm) 1.85-2.03 (m, 4H), 3.07 (t, J = 6.9 Hz,
2H), 4.04 (t, J = 5.7 Hz, 2H), 6.95 (d, J = 9.0 Hz, 2H), 7.23-7.59 (m, 10H), 7.97 (d, J =
7.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 20.84, 28.74, 38.00, 67.58, 114.65, 126.53,
126.63, 127.96, 128.04, 128.52, 128.63, 132.92, 133.56, 136.87, 140.74, 158.45, 199.91.

EUR (KBr): 2951, 2874, 1684, 1608, 1489, 1289, 1259, 1201, 1180, 1029, 831,
758, 689 cm".

HRMS: 330.1620 calculated for C23H2202, found 330.1621.

UV-VIS: €366 (cyclohexane) = 4.8 Lmol"cm"; €366 (benzene) = 4.2 Lmol‘lcm’l.

103

Melting Point: 132.0-132.8°C; white crystals.

4 -( 2 -Biphenyloxy )- I -phenylbutan-1 -one (Bz-3-02Bp)

1H NMR (CDC13, 300 MHz): 6 (ppm) 2.19 (tt, J = 5.7, 7.2 Hz, 2H), 3.07 (t, J =
7.2 Hz, 2H), 4.11 (t, J = 5.7 Hz, 2H), 7.02-7.12 (m, 2H), 7.32-7.64 (m, 10H), 7.90 (d, J =
7.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (Ppm) 23.74, 34.65, 67.28, 112.61, 120.91,
126.65, 127.71, 127.88, 128.38, 128.53, 129.47, 130.67, 130.91, 132.84, 136.63, 138.52,

155.56, 199.54.

FTIR (KBr): 3059, 2934, 1686, 1597, 1597, 1504, 1483, 1435, 1262, 1123,

1055, 1003, 754, 700 cm".
HRMS: 316.1463 calculated for szHzoOZ, found 316.1467.

UV-VIS: €366 (cyclohexane) = 2.9 Lmol"cm"; £366 (benzene) = 2.5 Lmol'lcm'l.

Colorless liquid.

5 -( 2 -Biphenyloxy )-1 -phenylpentan- I -one (Bz-4-02Bp)

‘H NMR (CDC13, 300 MHz): 6 (ppm) 1.75-1.93 (m, 4H), 2.93 (t, J = 6.9 Hz,
2H), 4.00 (t, J = 5.4 Hz, 2H), 6.94-7.05 (m, 2H), 724-757 (m, 10H), 7.86 (d, J = 8.1 Hz,
2H).

13C NMR (CDC13, 75 MHz): 6 (ppm) 21.08, 28.72, 38.09, 68.20, 112.45, 120.89,

126.75, 127.81, 128.01, 128.54 (large peak), 129.56, 130.88, 132.91, 136.87, 138.54,

153.37, 155.84, 200.05.

104

FTIR (KBr): 2946, 1684, 1597, 1483, 1433, 1264, 1199, 1128, 958, 775, 734
cm‘ .

HRMS: 330.1620 calculated for C23H2202, found 330.1632.

UV-VIS: 8366 (cyclohexane) = 4.7 Lmol’lcm°'; e366 (benzene) = 3.6 Lmol'lcm'l.

Melting Point: 67.0-68.0°C; white crystals.

4 -( 3 -Biphenyloxy )- I -phenylbutan- I -one (Bz-3-O3Bp)

1H NMR (CDC13, 300 MHz): 5 (ppm) 2.28 (tt, J = 6.0, 6.9 Hz, 2H), 3.23 (t, J =
6.9 Hz, 2H), 4.14 (t, J = 6.0 Hz, 2H), 6.89 (d, J = 8.1 Hz, 1H), 7.12-7.62 (m, 11H), 8.00
(d, J = 7.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 23.78, 34.87, 66.91, 113.15, 113.43,
119.61, 127.11, 127.34, 127.98, 128.54, 128.66, 129.70, 133.02, 136.85, 140.98, 142.68,
159.19, 199.48.

FTIR (KBr): 2974, 1687, 1583, 1568, 1468, 1309, 1215, 1016, 870, 758,688
cm' .

HRMS: 316.1463 calculated for szHzoOz, found 316.1463.

UV-VIS (cyclohexane): 8366 = 2.8 Lmol'lcm".

Melting Point: 91.0-92.5°C; white crystals.

105

4-(2-Naphthyloxy)- I -(p-methylphenyl)butan- 1 -one (MeBz-3-ONp)

1H NMR (CDC13, 300 MHz): 5 (ppm) 2.29 (tt, J = 6.1, 7.0 Hz, 2H), 2.39 (s, 3H),
3.21 (t, J = 7.0 Hz, 2H), 4.17 (t, J = 6.1 Hz, 2H), 7.11-7.16 (m, 2H), 7.22-7.46 (m, 4H),
7.68-7.78 (m, 3H), 7.90 (d, J = 8.3 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 21.63, 23.83, 34.87, 67.00, 106.62, 118.85,
123.54, 126.32, 126.73, 127.60, 128.15, 128.91, 129.27, 129.33, 134.43, 134.54, 143.84,

156.81, 199.26.

FTIR (KBr): 2965, 1684, 1630, 1601, 1466, 1367, 1257, 1180, 1120, 1016, 835,

821, 746 cm".
HRMS: 304.1463 calculated for C21H2002, found 304.1461.

UV-VIS: e366 (cyclohexane) = 2.7 Lmol'lcm"; 8366 (benzene) = 2.4 Lmol’lcm".

Melting Point: 80.0-81.0°C; white crystals.

5 -( 2-Naphthyloxy )-I -(p-methylphenyl)pentan-1 -one (MeBz-4-ONp)

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.90-2.05 (m, 4H), 2.41 (s, 3H), 3.06 (t, J
= 6.9 Hz, 2H), 4.13 (t, J = 5.9 Hz, 2H), 7.10-7.16 (m, 2H), 7.23-7.47 (m, 4H), 7.69-7.78
(m, 3H), 7.88 (d, J = 8.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 21.03, 21.62, 28.77, 37.97, 67.56, 106.49,
118.95, 123.48, 126.28, 126.69, 127.60, 128.16, 128.87, 129.25, 129.30, 134.69, 134.54,

143.73, 156.91, 199.67.

FTIR (KBr): 2957, 2930, 1678, 1601, 1464, 1388, 1257, 1215, 1180.970, 839,

806, 746 cm".

106

HRMS: 318.1620 calculated for szszOz, found 318.1604.
UV-VIS: €366 (cyclohexane) = 4.8 Lmol'lcm".

Melting Point: 125.0-126.5°C; white crystals.

4-(4-Biphenyloxy)-1 -(p-methylphenyl)butan- I -one (MeBz-3-O4Bp)

lH NMR (CDC13, 300 MHz): 5 (ppm) 2.25 (tt, J = 6.0, 7.1 Hz, 2H), 2.40 (s, 3H),
3.19 (t, J = 7.1 Hz, 2H), 4.10 (t, J = 6.0 Hz, 2H), 6.97 (d, J = 8.8 Hz, 2H), 7.22-7.58 (m,
9H), 7.89 (d, J = 8.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 21.63, 23.84, 34.78, 67.04, 114.73, 126.62,

126.69, 128.14 (large peak), 128.69, 129.26, 133.71, 134.42, 140.80, 143.83, 158.43,

199.22.

FTIR (KBr): 2948,2872, 1682, 1606, 1489, 1288, 1251, 1199, 1047, 839, 758,
687 cm".

HRMS: 330.1620 calculated for C23H2202, found 330.1619.

UV-VIS: 8366 (cyclohexane) = 2.8 Lmol"cm".

Melting Point: 97.0-98.0°C; white crystals.

107

E. Synthesis of (lo-Aryloxyalkyl Phenyl Ketones from (o-Bromoalkanols
(o—Aryloxyalkanoaryl ketones Ph-CO-(CH2)x-OAr (Ar = phenyl, 2-naphthy1,

2/3/4-biphenyl, x = 9, 10) were prepared in three steps following the route given below:

Q 0

Br-(CH2)x-OH : Br-(CH2)x-O o

 

ArONa, DMF

HCl, MeOH 0
Ar-O-(CH2)x-OH

Ar-O-(CH2)x-O o

11

soc12. DMF

Nal, acetone, reflux
Ar-O-(CH2)x-Cl > Ar-O-(CH2)x-I

 

NaCN, DMF

 

O. 11
Ar_0_(CH2)x 1. Bng@ , EtzO

< Ar-O-(CH2)x-CN
2. acetone, H20, H3O+, heat

 

Scheme 14. Synthesis of w-Aryloxyalkanophenyl ketones

THP-ether of lO-bromodecanol
Concentrated hydrochloric acid (0.1 mL) was added to a mixture of 2,3-
dihydropyran (2.18 g, 0.026 mol) and the lO-bromodecanol (3.1 g, 0.013 mol). Reaction

commenced immediately on shaking and was moderated by cooling in a ice-water bath.

108

The mixture was stirred for another 30 minutes at this temperature and then at room
temperature for 12 hrs. The mixture was diluted with diethyl ether (50 mL) and washed
with sodium hydrogen carbonate solution. The etheral layer was dried over MgSOa. The
solvent was evaporated and the crude product (90%) was used in the next step without
further purification.

THP-ether of IO-bromodecanol: 1H NMR (CDC13): 5 (ppm) 1.2-2.0 (m, 22H), 3.3 (t,

3H), 3.8 (t, 2H), 4.1 (t, 3H), 4.7 (t, 1H).

lO-Phenoxydecanol

A solution of THP-ether of 10-bromodecanol (3.9 g, 0.012 mol) and a
corresponding sodium phenolate, prepared from a phenol (1.1 g, 0.012 mol) and sodium
(0.3 g, 0.013 mol) in absolute methanol, in dimethylformamide (60 mL) was stirred at
50°C for 30 hrs. Distilled water was added (60 mL) and the product was extracted with
diethyl ether (3x 50 mL). The combined ether layer was washed with saturated sodium
chloride solution, distilled water, and dried over MgSOa. The solvent was evaporated
and the product was dissolved in methanol (50 mL) and concentrated hydrochloric acid
(10 mL), and the mixture was heated under reflux for 2 hrs. After cooling, the solution
was neutralized by the addition of an excess of sodium hydrogen carbonate solution,
diluted with diethyl ether (60 mL). The etheral layer was washed with distilled water and
dried over MgSOa. The solvent was evaporated and the crude product (75%) was used in

the next step without further purification.

109

9-Phenoxydecanol: lH NMR(CDC13): 8 (ppm) 1019 (m, 16H), 3.7 (t, 2H), 4.1 (t, 2H),

6.9-8.0 (m, 5H).

lO-Phenoxydecyl chloride

The 10-phenoxydecanol (2.5 g, 0.01 mol) was dissolved in dimethylformamide
(30 mL) and thionyl chloride (1.4 g, 0.012 mol) was added dropwise while stirring at
0°C. The mixture was then stirred at 50°C for 12 hrs. Distilled water was added (30 mL)
and the product was extracted with diethyl ether (3x 25 mL). The combined ether layer
was washed with saturated sodium chloride solution, distilled water, and dried over
MgSOa. The solvent was evaporated and the cmde product (90%) was used in the next
step without further purification.
IO-Phenoxydecyl chloride: lH NMR(CDC13): 6 (ppm) 1019 (m, 16H), 3.5 (t, 2H), 4.0

(t, 2H), 6.9-7.7 (m, 5H).

10-Phenoxydecyl iodide

The mixture of the 10-phenoxydecyl chloride (2.4 g, 0.009 mol) and sodium
iodide (5.0 g, 0.035 mol) in dry acetone (80 mL) was refluxed for 24 hrs. in dark. The
solvent was evaporated and distilled water (80 mL) was added. The product was
extracted with diethyl ether (50 mL, 2x 30 mL), the combined ether layer was washed

with saturated sodium thiosulfate solution and distilled water, and dried over MgSO4.

110

The solvent was evaporated and the product (90%) was either recrystallized from
hexane/ethyl acetate mixture (8:2).
IO-Phenoxydecyl iodide: 1H NMR (CDC13): 8 (ppm) 1.0-1.9 (m, 16H), 3.2 (t, 2H), 3.9

(t, 2H), 6.9-7.7 (m, 5H).

ll-Phenoxyundecanonitrile

A solution of the lO-phenoxydecyl iodide (2.9 g, 0.008 mol) and sodium cyanide
(0.44 g, 0.009 mol) in dimethylformamide (40 mL) was stirred at 50°C for 12 hrs.
Distilled water was added (40 mL) and the product was extracted with diethyl ether
(3x40 mL). The combined ether layer was washed with saturated sodium chloride
solution and distilled water, and was dried over MgSOa. The solvent was evaporated and
the crude product (85%) was purified by crystallization from hexane/ethyl acetate
mixture (7:3).
Note: The product has to be pure in order to get high yield in the next step.
II-Phenoxyundecanonitrile: 1H NMR (CDC13): 5 (ppm) 1.0-1.9 (m, 16H), 2.3 (t, 2H),

3.9 (t, 2H), 6.9-7.7 (m, 5H).

1l-Phenoxy-l-phenylundecan-1-one

In a 100 mL three necked round bottom flask equipped with a condenser and
purged with argon a solution of the ll-phenoxyundecanonitrile (1.8 g, 0.007 mol) in
diethyl ether (10 mL) was added dropwise to a solution of phenylmagnesium bromide,

prepared from phenyl bromide (1.1 g, 0.007 mol) and magnesium (0.19 g, 0.008 mol), in

111

diethyl ether (30 mL) at 5°C. After all the nitrile had been added, the mixture was stirred
at 35°C for 4 hrs. and poured into a mixture of distilled water and ice (about 50 mL). The
mixture was slowly neutralized by 10% hydrochloric acid solution and stirred at 35°C for
2 hrs. The product was extracted with diethyl ether (3x 40 mL), the combined ether layer
was washed with saturated sodium bicarbonate solution, distilled water, and dried over
MgSOa. The solvent was evaporated and the crude product (75%) was purified by flash

chromatography and recrystallized from hexane/ethyl acetate mixture (9:1).

1 1 -Phenoxy-1 -phenylundecan-1-one (Bz-lO—OPh)

‘H NMR (CDC13, 300 MHz): 6 (ppm) 1.25-1.50 (m, 12H), 165-1.85 (m, 4H),
2.96 (t, J = 7.2 Hz, 2H), 3.95 (t, J = 6.6 Hz, 2H), 6.90 (d, J = 7.7 Hz, 2H), 6.92, (t, J = 7.3
Hz, 1H), 7.21-7.26 (m, 2H), 7.40-7.52 (m, 2H), 7.55 (t, J = 7.3 Hz, 1H), 7.99 (d, J = 7.1
Hz, 2H).

l3C NMR(CDC13, 75 MHz): 6 (ppm) 24.36, 26.05, 29.29, 29.37 (large peak),
29.40, 29.46, 29.52, 38.62, 67.84, 114.47, 120.42, 128.05, 128.54, 129.39, 132.86,
137.08, 159.10, 200.61.

FTIR (KBr): 3067, 2916,2851, 1686, 1601, 1499, 1251, 1044, 750, 690 cm".

HRMS: 338.2246 calculated for C23H3oOz, found 338.2253.

UV-VIS: e366 (benzene) = 4.5 Lmol"cm".

Melting Point: 83.0-83.5°C; white crystals.

112

The following compounds were prepared according to the representative procedure

above.

I 0-(2-Naphthyloxy)- I -phenyldecan- I -one (Bz-9-ON p)

1H NMR (CDC13, 300 MHz): 6 (ppm) 1.30-1.59 (m, 10H), 1.65-1.90 (m, 4H),
2.95 (t, J = 7.2 Hz, 2H), 4.06 (t, J = 6.6 Hz, 2H), 7.10-7.17 (m, 2H), 7.27-7.34 (m, 1H),
7.39-7.50 (m, 3H, b, j), 7.54 (t, J = 7.2 Hz, 1H), 7.69-7.78 (m, 3H), 7.95 (d, J = 7.2 Hz,
2H).

13C NMR (CDC13, 75 MHz): 5 (Ppm) 24.31, 26.06, 29.20, 29.32 (large peak),
29.39 (large peak), 38.58, 67.92, 106.47, 118.99, 123.41, 126.22, 126.65, 127.59,
128.02, 128.52, 128.80, 129.25, 132.83, 134.57, 137.07, 157.05, 200.53.

EUR (KBr): 2914, 2849, 1682, 1631, 1597, 1512, 1468, 1448, 1352, 1213,
1126, 1028, 1001, 856, 804, 740, 689 cm".

HRMS: 374.2246 calculated for C26H3002, found 374.2248.

'UV-VIS: 8366 (cyclohexane) = 5.0 Lmol'lcm"; e366 (benzene) = 4.5 Lmol'lcm'l.

Melting Point: 59.5-60.0°C; white crystals.

I I -(2-Naphthyl0xy)-1 -phenylundecan-1-one (Bz-lO—ON p)
‘H NMR (CDC13, 300 MHz): 6 (ppm) 1.25-1.60 (m, 12H), 1.65-1.90 (m, 4H),
2.94 (t, J = 7.5 Hz, 2H), 4.05 (t, J = 6.6 Hz, 2H), 7.10-7.16 (m, 2H), 7.27-7.34 (m, 1H),

7.38-7.49 (m, 3H), 7.50-7.57 (m, 1H), 7.68-7.76 (m, 3H), 7.94 (d, J = 7.2 Hz, 2H).

113

13C NMR (CDC13, 75 MHz): 5 (ppm) 24.33, 26.02, 29.21, 29.36 (large peak),
29.30, 29.40, 29.43, 29.49, 38.59, 67.97, 106.48, 118.99, 123.40, 126.24,. 126.65,
127.59, 128.01, 128.52, 128.82, 129.56, 132.84, 134.57, 137.05, 157.06, 200.57.

FTIR (KBr): 2918, 2835, 1684, 1466, 1281, 1221, 837, 736, 690 cm'l.

HRMS: 388.2402 calculated for C27H3202, found 388.2409.

UV-VIS: £366 (benzene) = 4.6 Lmol'lcm".

Melting Point: 91 .0-92.0°C; white crystals.

10-(4-Biphenyloxy)- I -phenyldecan- I -one (Bz-9-O4Bp)

1H NMR (CDC13, 300 MHz): 6 (ppm) 1.32-1.52 (m, 10H), 1.65-1.85 (m, 4H),
2.97 (t, J = 7.5 Hz, 2H), 3.99 (t, J = 6.5 Hz, 2H), 6.98 (d, J = 8.8 Hz, 2H), 7.22-7.58 (m,
10H), 7.95 (d, J = 7.0 Hz, 2H).

13'C NMR (CDC13, 75 MHz): 6 (ppm) 24.36, 26.06, 29.30, 29.36 (large peak),
29.43 (large peak), 38.63, 68.07, 114.78, 126.60, 126.72, 128.08, 128.12, 128.57,
128.71, 132.90, 133.54, 137.10, 140.90, 158.73, 200.62.

FTIR (KBr): 2924, 2847, 1680, 1606, 1524, 1489, 1469, 1286, 1258, 1202,
1003, 839,758 cm".

HRMS: 400.2402 calculated for C23H3202, found 400.2396.

UV-VIS: £366 (benzene) = 4.6 Lmol’lcm".

Melting Point: 73.5-74.0°C; white crystals.

114

l l-(4-Biphenyloxy)-1 —phenylundecan- I -0ne (Bz-10-O4Bp)

‘H NMR(CDC13, 300 MHz): 6 (ppm) 1.25-1.55 (m, 12H), 1.62-1.88 (m, 4H),
2.95 (t, J = 7.5 Hz, 2H), 3.98 (t, J = 6.6 Hz, 2H), 6.95 (d, J = 9.0 Hz, 2H), 7.22-7.58 (m,
10H), 7.95 (d, J = 7.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 6 (ppm) 24.31, 26.01, 29.25, 29.34 (large peak),
29.40, 29.44 (large peak), 29.49, 38.59, 68.00, 114.72, 126.55, 126.66, 128.02, 128.05,
128.51, 128.66, 132.84, 133.46, 137.62, 140.83, 158.66, 200.56.

FTIR (KBr): 2915,2849, 1682, 1608, 1526, 1489, 1288, 1271, 1046, 987, 831,
688 cm".

HRMS: 414.2559 calculated for C29H3402, found 414.2547.

UV-VIS: 8366 (benzene) = 4.5 Lmol'lcm".

Melting Point: 125.0-126.0°C; white crystals.

1 0-( 2 -Biphenyloxy )-1 -phenyldecan- 1 -one (Bz-9-02Bp)

1H NMR (CDC13, 300 MHz): 8 (ppm) 1.22-1.48 (m, 10H), 1.66-1.82 (m, 4H),
2.97 (t, J = 7.2 Hz, 2H), 3.96 (t, J = 6.6 Hz, 2H), 6.96-7.05 (m, 2H), 7.26-7.58 (m, 10H),
7.97 (d, J = 7.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 8 (ppm) 24.28, 25.97, 29.08, 29.15, 29.30, 29.63,
29.69, 38.53, 68.28, 112.39, 120.65, 126.61, 127.72, 127.98, 128.48 (large peak),
129.54, 130.77 (large peak), 132.80, 136.99, 138.55, 155.95, 200.47.

FTIR (KBr): 2928,2855, 1688, 1597, 1483, 1435, 1262, 1122, 752, 698 cm".

HRMS: 400.2402 calculated for ngngOz, found 400.2402.

115

UV-VIS: 8366 (cyclohexane) = 4.9 Lmol‘lcm'l; €366 (benzene) = 4.5 Lmol"cm".

Colorless liquid.

1 I -(2-Biphenyloxy)- l -phenylundecan- I -one (Bz-lO-OZBp)

lH NMR(CDC13, 300 MHz): 6 (ppm) 1.20-1.43 (m, 12H), 1.65-1.80 (m, 4H),
2.95 (t, J = 7.5 Hz, 2H), 3.94 (t, J = 6.3 Hz, 2H), 6.94-7.04 (m, 2H), 7.24-7.58 (m, 10H),
7.95 (d, J = 7.8 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 24.35, 26.02, 29.12, 29.19, 29.35 (large
peak), 29.44, 29.47, 38.60, 68.36, 112.46, 120.67, 126.67, 127.74, 128.01, 128.48,
128.52, 129.58, 130.81, 130.85, 132.83, 137.06, 138.60, 156.00, 200.56.

FTIR (KBr): 2921, 1692, 1595, 1476, 1435, 1263, 1232, 1122, 756, 696 cm".

HRMS: 414.2559 calculated for C29H3402, found 414.2541.

UV-VIS: £366 (benzene) = 4.6 Lmol'lcm’l.

Melting Point: 45.0-46.0°C; white crystals.

1 0-( 3 -Biphenyloxy )- l -phenyldecan- I -one (Bz-9-O3Bp)

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.22-1.55 (m, 10H), l.68-1.90 (m, 4H),
2.95 (t, J = 7.5 Hz, 2H), 4.01 (t, J = 6.5 Hz, 2H), 6.87 (d, J = 8.1 Hz, 1H), 7.10-7.62 (m,
11H), 7.96 (d, J = 6.6 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 24.23, 25.92, 29.19, 29.22, 29.24 (large
peak), 29.26, 38.48, 67.89, 113.21, 113.47, 119.43, 127.11, 127.30, 128.02, 128.53,

128.70, 129.65, 132.85, 137.01, 141.11, 142.62, 159.42, 200.39.

116

FTIR (KBr): 2924, 2847, 1680, 1606, 1489, 1287, 1258, 839, 758,689 cm'l.
HRMS: 400.2402 calculated for ngngOz, found 400.2400.
UV-VIS (cyclohexane): 8366 = 4.9 Lmol"cm".

Melting Point: 55.0-56.0°C; white crystals.

1 1 -( 3 -Biphenyloxy )- 1 -phenylundecan-1-one (Bz-lO-OBBp)

1H NMR (CDC13, 300 MHz): 5 (ppm) 1.22-1.50 (m, 12H), 1.65-1.85 (m, 4H),
2.95 (t, J = 6.9 Hz, 2H), 4.00 (t, J = 6.6 Hz, 2H), 6.88 (d, J = 8.1 Hz, 1H), 7.10-7.60 (m,
11H), 7.94 (d, J = 7.2 Hz, 2H).

13C NMR (CDC13, 75 MHz): 5 (ppm) 24.36, 26.04, 29.31, 29.35 (large peak),
29.41, 29.44, 29.50, 38.61, 68.02, 113.23, 113.50, 119.43, 127.17, 127.33, 128.04,
128.52, 128.68, 129.68, 132.83, 137.08, 141.15, 142.67, 159.48, 200.58.

FTIR (KBr): 3057, 2915,2851, 1687, 1601, 1471,1302, 1211, 756, 690 cm".

HRMS: 414.2559 calculated for C29H3402, found 414.2550.

UV-VIS (benzene): 8366 = 4.5 Lmol'lcm".

Melting Point: 56.0-57.0°C; white crystals.

4.2.2 Synthesis of 4-(2-aryloxyethyl)oxy-1-phenylbutan-1-ones
4-(2-Aryloxyethyl)oxy- 1 -phenylbutan-1-ones Ph-CO-(CH2)3-O-(CH2)2-O-Ar (Ar

= phenyl, 4-biphenyl) were prepared in four steps following the route given below:

117

O
HCl,

OH O 0 0 NaI, acetone 0 0
‘:(:1 T [Cl 7 E1

 

l. ArONa, DMF
2. HCl, MeOH

 

Ar

1. NaH, THF
0 1 [OH

O-Ar

 

3. acetone, H20, H3O+, heat

Scheme 15. Synthesis of 4-(2-aryloxyethy1)oxy-l-phenylbutan-l-ones

THP-ether of 2-iodoethanol

Concentrated hydrochloric acid (1 mL) was added to a mixture of 2,3-
dihydropyran (21.3g, 0.25 mol) and 2-chloroethanol (14 g, 0.17 mol). Reaction
commenced immediately on shaking and was moderated by cooling in a ice-water bath.
The mixture was stirred for additional 30 minutes at this temperature and then at room
temperature for 12 hrs. The mixture was diluted with diethyl ether (200 mL) and washed
with sodium hydrogen carbonate solution. The etheral solution was dried over MgSO4.
The solvent was evaporated, the crude product was dissolved in acetone (250 mL), and

sodium iodide (50 g, 0.33 mol) was added. The mixture was refluxed for 24 hrs.

118

Distilled water (250 mL) was added and the product was extracted with diethylether. The
combined organic layer was washed with saturated sodium thiosulfate solution and
distilled water, and dried over MgSOa. The solvent was evaporated and the crude
product was used without any further purification (60%).

THF-ether of 2-iodoethanol: 1H NMR (CDC13): 6 (ppm) ): 1.2-2.0 (m, 6H), 3.1-4.1 (m,

6H), 4.7 (t, 1H).

2-Phenoxyethanol

A solution of THP-ether of 2-iodoethanol (3.1 g, 0.012 mol) and sodium
phenolate, prepared from a phenol (1.1 g, 0.012 mol) and sodium (0.3 g, 0.013 mol) in
absolute methanol, in dimethylformamide (60 mL) was stirred at 50°C for 30 hrs.
Distilled water was added (60 mL) and the product was extracted with diethyl ether (3x
50 mL). The combined ether layer was washed with saturated sodium chloride solution,
distilled water, and dried over MgSO4. The solvent was evaporated and the product was
dissolved in methanol (50 mL) and concentrated hydrochloric acid (10 mL), and the
mixture was refluxed for 2 hrs. After cooling, the solution was neutralized by the
addition of an excess of sodium hydrogen carbonate solution and diluted with diethyl
ether (50 mL). The organic layer was washed with distilled water, dried over MgSO4,
and the solvent was evaporated. The crude product (75%) was used in the next step
without further purification.
2-Phen0xyethanol: lH NMR(CDC13): 6 (ppm) 2.1 (t, 1H), 3.9 (t, 2H), 4.1 (t, 2H), 6.8-

7.5 (m, 5H).

119

4-(2-Phenoxyethyl)oxy-1-phenylbutan-1-one

2-Phenoxyethanol (1.2 g, 0.009 mol) from the previous step was dissolved in dry
tetrahydrofuran and NaH (0.24 g, 0.01 mol) was added while stirring. Ethylene glycol
ketal of 4-iodo-l-phenylbutan-l-one (2.5 g, 0.009 mol) (Procedure 4.2.3) was added
dropwise to the mixture with temperature kept under 30°C. The mixture was stirred at
50°C for 48 hrs. The mixture was washed with saturated sodium chloride solution and
distilled water, and dried over MgSO4. Tetrahydrofuran was evaporated and acetone (30
mL) and 10% hydrochloric acid were added. The mixture was stirred at 40°C for 24 hrs.,
cooled, and distilled water (30 mL) was added. The product was extracted with diethyl
ether (3x 25 mL). The combined ether layer was washed with saturated sodium
bicarbonate solution, distilled water, and dried over MgSOa. The solvent was evaporated
and the crude product (70%) was purified by flash chromatography and recrystallized

from hexane/ethyl acetate (8:2).

4-(2-Phenoxyethyloxy)- 1 -phenylbutan-1 -one (Bz-3-O-2-OPh)
1H NMR (CDC13, 300 MHz): 5 (ppm) 2.05 (tt, J = 6.3, 8.2 Hz, 2H), 3.07 (t, J = 8.2 Hz,
2H), 3.62 (t, J = 6.3 Hz, 2H), 3.78 (t, J = 5.1 Hz, 2H), 4.09 (t, J = 6.3 Hz, 2H), 6.86-6.96
(m, 3H), 7.21-7.29 (m, 2H), 7.39-7.56 (m, 3H), 7.95 (d, J = 7.8 Hz, 2H).

l3’c NMR(CDC13, 75 MHz): 6 (ppm) 24.16, 35.01, 67.24, 69.22, 70.41, 114.59,

120.81, 128.04, 128.52, 129.39, 132.94, 136.99, 158.77, 200.03.

120

FI‘IR (KBr): 2957, 2878, 1686, 1599, 1450, 1361, 1254, 1120, 1045, 893,758,
691 cm'l.

HRMS: 284.1413 calculated for C13H2002, found 284.1412.

UV-VIS: e366 (cyclohexane) = 3.9 Lmol'lcm".

Melting Point: 53.0—54.0°C; white crystals.

The following compound was prepared according to the representative procedure above.

4-(4-Biphenyloxyethyloxy)-1 -phenylbutan- I -one (Bz-3-O-2-O4Bp)
1H NMR (CDC13, 300 MHz): 5 (ppm) 2.06 (a, J = 6.0, 6.9 Hz, 2H), 3.10 (t, J = 6.9 Hz,
2H), 3.64 (t, J = 6.0 Hz, 2H), 3.80 (t, J = 4.5 Hz, 2H), 4.14 (t, J = 4.8 Hz, 2H), 6.93-7.00
(d, J = 8.7 Hz, 2H), 7.25-7.56 (m, 10H), 7.95 (d, J = 6.9 Hz, 2H).

13C NMR (CDC13, 75 MHz): 8 (ppm) 24.12, 34.96, 67.43, 69.20, 70.39, 114.86,
126.62, 126.67, 127.99, 128.05, 128.50, 128.67, 132.92, 133.85, 136.97, 140.72, 158.34,
199.99.

Fl‘IR(KBr): 2932,2874, 1684, 1608, 1489, 1448, 1288, 1249, 1134, 1047, 831,
758, 688 cm".

HRMS: 360.1725 calculated for C24H2402, found 361.1802 (+FAB, MH+).

UV-VIS: e366 (cyclohexane) = 3.8 Lmol"cm".

Melting Point: 81 .5-82.0°C; white crystals.

121

4.2.3 Synthesis of Arylethyl Ethers
Arylethyl ethers Ar-O-Et (Ar = phenyl, 2-naphthy1, 2/3/4-biphenyl) were

prepared in a single step according to the following procedure.

2-Ethoxynaphthalene

A solution of ethyl iodide (3.1 g, 0.02 mol) and sodium phenolate, prepared from
a phenol (1.9 g, 0.02 mol) and sodium (0.5 g, 0.022 mol) in absolute methanol, in
dimethylformamide (100 mL) was stirred at 50°C for 30 hrs. Distilled water was added
(50 mL) and the product was extracted with diethyl ether (3x 50 mL). The combined
ether layer was washed with saturated sodium chloride solution, distilled water, and
dried over MgSO4. The solvent was evaporated and the crude product (85%) was

purified by recrystallization from hexane/ethyl acetate (7:3).

2-Ethoxynaphthalene

1H NMR (CDC13): 5 (ppm) 1.49 (t, J = 7.2 Hz, 3H), 4.15 (q, J = 6.9 Hz, 2H), 7.13 - 7.79
(m, 7H).

13C NMR (CDC13, 75 MHZ): 5 (ppm) 14.80, 63.38, 106.41, 118.96, 123.46, 126.26,
126.67, 127.60, 128.83, 129.31, 134.55, 156.86.

FTIR (KBr): 2988, 2876, 1628, 1599, 1466, 1388, 1257, 1184, 1109, 1041, 750 cm].

Melting Point: 37.0-38.0°C; white crystals.

The following compound was prepared according to the representative procedure above.

122

4-Ethoxybiphenyl

1H NMR (CDC13): 5 (ppm) 1.44 (t, J = 6.6 Hz, 3H), 4.07 (q, J = 7.2 Hz, 2H), 6.95 - 7.57
(m, 9H).

13’C NMR (CDC13, 75 MHz): 5 (Ppm) 14.87, 63.46, 114.68, 126.59, 126.68, 128.09,
128.69, 133.53, 140.81, 158.46.

FTIR (KBr): 2965, 1605, 1522, 1396, 1271, 1201, 1051, 837, 763, 690 cm".

Melting Point: 73.0-74.0°C; white crystals.

4.3 Ultraviolet and Phosphorescence Spectroscopy

Ultraviolet (UV) spectra of the ketones were taken in cyclohexane and benzene
for the purpose of measuring their molar absorptivity, e, at 366 nm. These data are listed
in Tables 7-9. This information was particularly important for quantum yield
experiments where the quantum yields were corrected for optical density of both the
ketone and the actinometer. Also, molar absorptivities were used for indirect calculation
of the calibration factor for HPLC measurements. Some ketones used in this work were
weakly soluble in cyclohexane and therefore it was difficult to obtain molar
absorptivities in this solvent. Typical maximum ketone concentrations in cyclohexane
were 10'2 M. Since the molar absorptivities at 366 nm were found to be very low, 3-5

Lmol'lm' , the effect of instrumental noise is expected to be highm Maximum

123

concentrations of some longer ketones with 7 to 14-atom tethers were only 3-5x10'3 M,
so molar absorptivity measurements were below the level of reliability. Absorptivities
£366 of those compounds were taken in benzene in order to have a comparison for a
solvent where all ketones are relatively soluble. Their 8366 values in cyclohexane were

then interpolated from £366 in benzene. Absorptivities of long bichromophores (x = 7-14)

in benzene were found to be essentially constant.

Table 7. Molar Absorptivities of Bz-n-OPh, MeBz-n-OPh, and Bz-3-O-2-0Ph

 

 

 

Bichromophore e366, Lmol'lm'l €366, Lmol"m'l
(cyclohexane) (benzene)

Bz-3-OPh 3.1 2.5
Bz-4-0Ph 4.5 4.0
Bz-S-OPh 4.8

Bz-7-0Ph 5.0 4.4
Bz- 10-0Ph 4.5
Bz— l 1 -OPh 4.5
MeBz-3-0Ph 2.9 2.3
MeBz-4-0Ph 4. 1 3.7
MeBz-S-OPh 4.9 4.0
Bz—3-O-2-0Ph 3.9

 

 

 

 

124

Table 8. Molar Absorptivities of Bz-n—O4Bp, Bz-n-O3Bp, and Bz-n-02Bp

 

 

 

 

 

Bichromophore e366, Lmol'lm'l e366, Lmol'1m'l
(cyclohexane) (benzene)

Bz-3-O4Bp 3.0 2.4
Bz-4-O4Bp 4.8 4.2
Bz-5-O4Bp 4.9 4.3
Bz-6-O4Bp 4.9 4.4
Bz-7-O4Bp 4.9 4.5
Bz-9~O4Bp 4.6
Bz-10-O4Bp 4.5
Bz-l 1-O4Bp 4.6
Bz-14-O4Bp 4.5
Bz-3-O2Bp 2.9 2.5
Bz-4-O2Bp 4.7 3.6
Bz-5-02Bp 4.8

Bz-6-02Bp 4.8 4.3
Bz-7-02Bp 4.8

Bz-9-O2Bp 4.9 4.5
Bz- 10—02Bp 4.6
Bz-l l-O2Bp 4.5
Bz-14-O2Bp 4.6
Bz-3-03Bp 2.8

Bz-6-O3Bp 4.9

Bz-7-O3Bp 4.8

Bz-9-O3Bp 4.9 4.4
Bz- 10-O3Bp 4.5
Bz-14-O3Bp 4.6

 

 

125

Table 9. Molar Absorptivities of Bz-n-ONp

 

 

 

Bichromophore e366, Lmol'lm'l e366, Lmol'lm'l
(cyclohexane) (benzene)
Bz-3-0Np 3.0 2.4
Bz-4-ONp 5.0 4.0
Bz-S-ONp 5.0 4.2
Bz-6-0Np 5. l 4.3
Bz-7-ONp 5.0 4.4
Bz-9-0Np 5.0 4.5
Bz- 1 O-ONp 4.6
Bz-l 1-ONp 4.5
Bz-14-0Np 4.6

 

 

 

 

Table 10. Molar Absorptivities of MeBz-n-ONp, MeBz-n-O4Bp, Bz-3-O-2-O43p, and

 

 

actinometers
Bichromophore e366, Lmol"m'l e366, Lmol'lm’l
(cyclohexane) (benzene)
MeBz-3-0Np 2.7 2.4
MeBz-4-ONp 4.8
MeBz-S-ONp 4.8
MeBz-6-0Np 4.9 4.3
MeBz-7-0Np 4.4
MeBz-l 1 -ONp 4.5
MeBz-3-04Bp 2.8
Bz-3-O-2-O-4Bp 3.8
valerophenone 4.8 4.0
4—methylvalerophenone 4.7 3.8

 

 

 

 

 

126

Table 11. Phosphorescence Emission Data

 

 

Chromophore 0,0 band“ 0,0 band (1it.)
(nm) (kcal) (nm) (kcal)
Acetophenone 387 73.9 74.1'08
4-Methylacetophenone 394 72.6 392'09 72.9
2-Ethoxynaphtha1ene 460 62.2 462”0 61.9
4-Ethoxybiphenyl 444 64.4 66.0‘”
3-Ethoxybipheny1 433 66.0 67.0“1
2-Ethoxybipheny1 438 65.3 67.0'll
Valerophenone 390 73.3 393'12 72.7
Bz-S-OPh 387 73.9
Bz-l l-OPh 386 74.0

 

 

 

 

 

“0.001M solutions in 2-methy1tetrahydrofuran at 77K. Excitation wavelength used for all
measurements was 300 nm or 330 nm.

Phosphorescence emission spectra were measured at 77K in a 2-
methyltetrahydrofuran glass in a 4 mm Pyrex sample tube. Those data and literature
values are summarized in Table 11. The spectra showing emission of all chromophores
used in this work are shown in Figure 20. The spectra of the model phenoxy ketones did

not differ significantly from those of the chromophore molecules (Table 11).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

127

AP
300 400 Mm) 500 600
ZBtONp
400 500 Mm) 600 700
3BOBp
4 E
.5
I I I I I I
400 Mm) 50 600
Figure 20. Phosphorescence emission

methylacetophenone (MeAP),

 

 

 

 

 

MeAP
r I I I I
400 A (am) 500
4EtOBp

 

 

 

 

I I T
500 x (m) 600

 

 

 

 

400 x (m) 50 I 600 '
spectra of acetophenone (AP), 4-
2-ethoxynaphthalene (2EtONp), 4-ethoxybipheny1

(4EtOBp), 3-ethoxybiphenyl (3EtOBp), and 2-ethoxybiphenyl (2EtOBp) chromophores

in 2-methy1tetrahydrofuran at 77K.

128

4.4 Photochemical Procedures and Experiments

4.4.1 Purification of Solvents

Cyclohexane

Reagent-grade cyclohexane (Aldrich) (3.5 L) was stirred with concentrated
sulfuric acid (0.5 L) for 2 days. The cyclohexane layer was separated and was washed
with 100 mL portions of concentrated sulfuric acid several times until the acid layer
remained colorless. The cyclohexane was then washed with deionized water and
saturated hydrogen carbonate solution. The cyclohexane layer was separated, dried over
magnesium sulfate, and filtered. The solvent was refluxed over calcium hydride (100 g)
for 48 hours, and distilled through a 0.3 meter column. A high reflux ratio was
maintained, and the initial 10% was discarded. The middle portion (ca. 80%, b.p.: 81°C)

was collected and used in photochemical experiments.

Benzene

Reagent-grade benzene (Aldrich) (3.5 L) was stirred with concentrated sulfuric
acid (0.5 L) for 2 days. The benzene layer was separated and was washed with 100 mL
portions of concentrated sulfuric acid several times until the acid layer remained
colorless. The benzene was then washed with deionized water and saturated hydrogen
carbonate solution. The benzene layer was separated, dried over magnesium sulfate, and
filtered. Phosphorus pentoxide (100 g) was added, the solution was refluxed for 48

hours, and distilled through a 1 meter column packed with glass helices. A high reflux

129

ratio was maintained and the initial 10% was discarded. The middle portion (ca. 80%,

b.p.: 80°C) was collected and used in photochemical experiments.

4.4.2 Purification of Standards, lntemal Standard, Actinometer, and Quencher

Acetophenone (AP)

Acetophenone (Aldrich) was purified by fractional distillation and used without

further purification.

4-Methylacetophenone (MeAP)

4-Methylacetophenone (Aldrich) was purified by fractional distillation and used

without further purification.

Methyl Benzoate (MeBe)

Methyl benzoate (Aldrich) was purified by fractional distillation and used

without further purification.

Valerophenone (VP)

Valerophenone (Aldrich) was purified by fractional distillation.

2,5-Dimethyl—2,4-hexadiene (DMHD)
Special care was taken to insure that only pure, sublimed quencher 2,5-dimethyl-

2,4-hexadiene (Chemical Samples Co.) was used. Even nicely crystalline material

130

present at the frozen liquid surface contained some amount of impurities which could

adversely affect the results of a quenching experiment.

4.4.3 Glassware

All photolysis glassware (syringes, volumetric flasks, pipettes, etc.) were rinsed
with acetone and deionized water and boiled in a solution of Alconox laboratory
detergent in deionized water for 24 hrs. They were then rinsed with deionized water and
boiled in deionized water for 24 hrs. This cycle was repeated 3 times. After a final rinse
with deionized water, the glassware was oven dried at 140°C overnight and cooled to
room temperature before use.

Ampoules used for irradiation were made from l3x100 mm Pyrex culture tubes
by flame heating them approximately 2 cm from the top with an oxygen - natural gas

torch and drawing them to a uniform 15 cm length.

4.4.4 Sample Preparation, Degassing, and Irradiation Procedures

All solutions were prepared by directly weighing the desired material into
volumetric flasks or by dilution of stock solutions. Samples were prepared: 2.8-mL
aliquots were placed via syringes in 13x 100 Pyrex tubes that were then degassed in three
freeze—pump-thaw cycles using liquid nitrogen before being sealed with an oxygen -

natural gas torch while still under vacuum. Samples were irradiated in a “merry-go-

131

round” apparatusl '3 immersed in a water bath. All measurements were conducted at 366
nm excitation. The 366 nm band was isolated from a medium pressure 450 W Hanovia

mercury arc lamp by filtration with Corning 7-83 filters.

4.4.5 Quenching Studies

Bichromophore 0.001M solutions in cyclohexane or benzene with different
concentrations of the quencher (2,5-dimethyl-2,4-hexadiene) were used. Valerophenone
solutions were irradiated simultaneously as actinometer for quantum yield
measurements.”4 Triplet lifetimes were determined by Stem-Volmer quenching
techniques. The slope k4,, in the plot (Do/(1) versus [Q] was calculated using a method of
least squares with the intercept in 64¢ = 1 for [Q] = 0 by definition.

For each Stem-Volmer measurement, four solutions of the bichromophore with
different concentrations of the quencher and one solution without the quencher were
prepared. Two tubes of each solution were used in the irradiation. Two bichromophore
solutions and two actinometer solutions were prepared for quantum yield measurements
and two tubes of each were irradiated. The Stem-Volmer and quantum yield
measurements were then repeated with new solutions.

The 0.001 M valerophenone solutions were used for irradiations of less than 5
hours. For long irradiations, an appropriate number of consecutive valerophenone
samples, changed every 5 hours, was used. The total acetophenone yield was then

calculated as a sum over all partial measurements .

132

4.4.6 Photoproduct Identification
The only photoproducts common for all photoreactions in this work are

acet0phenone and 4-methylacetophenone. Their direct identification was based on 1H

NMR, 13C NMR, and HPLC comparison with the standards.

NMR identification

The 0.1 M solution in the NMR tube of the bichromophore and model phenoxy
ketone (Bz-3-0Ph, Bz-S-OPh, Bz-5-04Bp, MeBz-S-ONp) were irradiated at 366 nm
until the conversion of the photoproduct was about 50%. 1H NMR spectra were taken
and photoproduct peaks (AP, MeAP, olefinic double bond) were compared with NMR
spectra of the standards. The 0.1 M solution of Bz-5-O43p was irradiated at 313 nm and
the photoproduct AP was isolated by flash chromatography (hexane/ethyl acetate mixture

9:1). 1H NMR and ‘3 C NMR spectra were compared with those of the standard.

HPLC identification

For every set of measurements, a solution of the standard and the bichromophore,
the irradiated sample, and the mixture of both, were compared and the peaks
corresponding to the photoproduct identified. HPLC conditions were developed so as to
ensure that the peaks of the photoproduct and the internal standard (methyl benzoate) did
not contain any impurities. All chemicals used in irradiations were analyzed before each

experiment for their purity by HPLC.

133

4.4.7 Analysis of Photoproducts

The photoproduct yields (acetophenone or 4-methylacetophenone) were
determined by HPLC and the reaction conversion was kept under 15%. Larger amount of
photoproduct can absorb incoming light and it would increase experimental error. The
photoproducts were monitored at 250 or 265 nm in the HPLC detector because the
photoproduct molar absorptivity is relatively high in this region. HPLC conditions were
developed in order to get the photoproduct and standard peaks as far from the much
larger bichromophore and quencher peaks as possible.

Each sample was measured twice. In case that the two values differed by more
than 5%, the measurement was repeated.

The concentration of the photoproduct, [P], was obtained using Equation 11,

[P] = C x [MeBe] x Ap / AMcBe (Equation 11)
where [P] is the concentration of the photoproduct.(AP, MeAP), C is the calibration
constant for the photoproduct, [MeBe] is the concentration of the standard methyl
benzoate (MeBe); Ap is the integrated area for the photoproduct: AM: for acetophenone;

AMcAp for 4-methylacetophenone; and A‘s is the integrated area for the internal standard.

134

Table 12. Calibration constants

 

 

 

 

 

 

Photoproduct wavelength C
AP 250 0. 144
AP 265 l .280
MeAP 250 0.036
MeAP 265 0.440

 

The calibration constant C was obtained from the calibration curve. The values of

C for 250 and 265 nm are shown in Table 12.

The correlation coefficients were calculated in KaleidaGraph 3.0 software using a

standard linear regression calculation.

HPLC condition sets used in Stem-Volmer and quantum yield studies are

summarized in Table 13.

Table 13. HPLC Condition Sets.

HPLC condition set Hexane/AcOEt % ratio Detection wavelength (nm)
1 97/3 250
2 93/7 250
3 97/3 265
4 93/7 265
5 98/2 265
6 95/5 265
7 95/5 250
8 98/2 250
9 97/3 => 80/20“ 250

10 99/1 => 90/10“ 250

“20 min concentration gradient.

135

4.4.8 Bimolecular Quenching

The bimolecular self-quenching rate constants were obtained for the donor and
acceptor chromophore molecules. The 2-ethoxynaphthene or 4-ethoxybiphenyl solutions
with the mixture of valerophenone of the same concentration (0.1 - 0.001 M) in
cyclohexane were irradiated under the same condition as quenching experiments
described above. The dependence of bimolecular quenching on concentration was found
to be linear. For 0.001 M concentration, the quenching was found to be 8x10° M'ls’l and

3x10° M'ls’l for 2-ethoxynaphthene and 4-ethoxybiphenyl, respectively.

136

Table 14. Stem-Volmer Quenching of the Acetophenone Formation in Bz-3-0Ph with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
AAP/AMene [AP], 10.5 M [Q], M <1>J¢
0.350 3.22 0.0000 1.00
0.309 2.85 0.0055 1.13
0.260 2.40 0.01 1 1 1.34
0.236 2.17 0.0167 l..48
0.202 1.86 0.0222 1.73

 

 

 

 

L m = 31.10

[Ketone] -.-. 1.0200x10'3 M. [MeBe] = 6.3841x104 M. Irradiation for 2.5 h. HPLC
condition set 1. Correlation coefficient = 0.995.

 

 

 

 

 

 

Run2

Air/Ann. [AP], 10" M 101. M mm

0.304 4.64 0.0000 1.00

0.264 4.02 0.0055 1.15

0.240 3.66 0.011 1 1.26

0.210‘ 3.21 0.0166 1.45

0.173' 2.64 0.0222 1.76

m = 30.31

 

[Ketone] = 1.0154x10'3 M. [MeBe] = 1.0606x10'3 M. Irradiation for 3.0 h. HPLC
condition set 1. *Average of 1 tube. Correlation coefficient = 0.980.

137

Table 15. Stem-Volmer Quenching of the Acetophenone Formation in Bz-4—0Ph with
2,5-Dimethy1-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run 1

AAP/AMeBe [AP], 10.5 M [Q], M (Do/‘1’
0.659 6.07 0.0000 1.00

0324* 2.99 0.0055 2.03

0.208 1.92 0.0111 3.16

0.145 1.33 0.0166 4.56

0.1 10* 1.01 00222 6.00

qu = 216.4

 

[Ketone] = 0.9948x10'3 M. [MeBe] = 6.3841x10“1 M. Irradiation for 3.0 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.997.

 

 

 

 

 

 

Run2

Alp/tip,Be [AP], 10" M [Q], M we

0.483 7.37 0.0000 1.00

0.234 3.57 0.0047 2.07

0.145 2.21 0.0093 3.34

0.104 1.59 0.0140 4.63

0.087‘ 1.33 0.0186 5.54

kq‘c = 248.4

 

[Ketone] = 0.9909x10'3 M. [MeBe] = 1.0606x10'3 M. Irradiation for 4.0 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.998.

138

Table 16. Stem-Volmer Quenching of the Acetophenone Formation in Bz-S-OPh with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run]

tau/AM... [AP], 10" M [Q], M (Do/(b
0.679 6.25 0.0000 1.00

0.436“ 4.02 0.0055 1.56

0.354 3.26 0.0111 1.92

0.272‘ 2.51 0.0166 2.49

0.226 2.08 0.0222 3.00

kg: = 89.2

 

[Ketone] = 1.0077x10’3 M. [MeBe] = 6.3841x10'4 M. Irradiation for 3.0 h. HPLC
condition set 2. ‘Average of 1 tube. Correlation coefficient = 0.998.

 

 

 

 

 

 

Run2

Ara/Ann. [AP], 10" M [Q], M 9.49

0.540 8.25 0.0000 1.00

0.384 5.86 0.0047 1.41

0.304‘ 4.64 0.0093 1.78

0.245’ 3.74 0.0140 2.21

0.197" 3.00 0.0187 2.75

kq‘t = 89.8

 

[Ketone] = 1.0211x10‘3 M. [MeBe] = 1.0606x10'3 M. Irradiation for 4.0 h. HPLC
condition set 2. “Average of 1 tube. Correlation coefficient = 0.997.

139

Table 17. Stem-Volmer Quenching of the Acetophenone Formation in Bz-7-OPh with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Air/Ann. [AP]. 10" M 101. M «9.10
0.656 8.88 0.0000 1.00
0.399 5.40 0.0106 1.64
0.276 3.73 0.0213 2.38
0.217" 2.94 0.0319 3.02
0.173‘ 2.34 0.0425 3.79

 

 

 

 

kg: = 64.6 1

 

[Ketone] = 1.0291x10'3 M. [MeBe] = 9.4014x10“1 M. Irradiation for 3.4 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.990.

 

 

 

 

 

 

Run2

tin/AM,“ [AP], 10" M [Q], M <I>.,/<1>

0.333 5.65 0.0000 1.00

0.239“ 4.07 0.0065 1.39

0.185 3.15 0.0130 1.79

0.154" 2.61 0.0195 2.16

0.130‘ 2.20 0.0260 2.56

kqt = 60.1

 

[Ketone] = 1.0257x10'3 M. [MeBe] = 1.1825x10’3 M. Irradiation for 3.0 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.999.

140

Table 18. Stem-Volmer Quenching of the Acetophenone Formation in Bz—lO-OPh with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Air/Ana. [AP]. 10" M [01, M ¢J<I>
0.535 7.24 0.0000 1.00
0.312 4.23 0.0106 1.71
0.249 3.37 0.0213 2.15
0.198 2.68 0.0319 2.70
0.155‘ 2.10 0.0425 3.44

 

 

 

 

L M = 56.1

[Ketone] = 9.8679x10“1 M. [MeBe] = 9.4014x10‘4 M. Irradiation for 3.4 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.996.

 

 

 

 

 

 

Run2

AAn/AMene [AP], 10" M [Q], M 9.8»

0.320 4.61 0.0000 1.00

0.203 2.92 0.0106 1.58

0.137" 1.97 0.0213 2.33

0.117" 1.68 0.0319 2.73

0.090 1.30 0.0426 3.55

kq'r = 58.4

 

[Ketone] = 1.0045x10'3 M. [MeBe] = 1.0107x10'3 M. Irradiation for 3.0 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.996.

141

Table 19. Stem—Volmer Quenching of the Acetophenone Formation in Bz-l l-OPh with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run]
AAP/AMeBe [AP]. 10" M [Q]. M <I>J<I>
0.326 4.69 0.0000 1.00
0.209‘ 3.01 0.0106 1.56
0.155‘ 2.23 0.0213 2.10
0.1 15* 1.65 0.0319 2.85
0.092“ 1.33 0.0426 3.54
kq't = 57.8 1

 

[Ketone] = 1.0128x10'3 M. [MeBe] = 1.0107x10'3 M. Irradiation for 3.0 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.998.

 

 

Run 2
AAn/AMene [AP]. 10" M [0]. M 9.19
0.462 6.65 0.0000 1.00
0.361 5.19 0.0047 1.28
0.302‘ 4.35 0.0094 1.53
0.256‘ 3.68 0.0142 1.81
0.217“ 3.12 0.0189 2.13

 

 

 

 

l kq‘t = 58.5 1

[Ketone] = 9.6455x10“4 M. [MeBe] = 1.0107x10'3 M. Irradiation for 3.0 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.999.

142

Table 20. Stem-Volmer Quenching of the Acetophenone Formation in Bz-3-O-2-0Ph
with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Air/Ann. [AP], 10" M [Q], M 9.19
0.653 9.13 0.0000 1.00
0.560 7.82 0.0068 1.17
0.482 6.73 0.0135 1.36
0.425‘ 5.94 0.0203 1.54
0.382 5.33 0.0270 1.71

 

 

 

 

qu = 26.3 I

 

[Ketone] = 1.0165x10'3 M. [MeBe] = 0.9725x10'3 M. Irradiation for 4 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run2
Air/Ann. [AP]. 10“ M 101. M 0.19
0.744 9.43 0.0000 1.00
0.625 7.91 0.0074 1.19
0.559“ 7.09 0.0149 1.33
0.510 6.46 0.0224 1.46
0.429 5.44 0.0298 1.73
qu = 23.1

 

[Ketone] = 0.9741x10'3 M. [MeBe] = 0.8814x10'3 M. Irradiation for 5 h. HPLC
condition set 1. ’Average of 1 tube. Correlation coefficient = 0.990.

143

Table 21. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in
MeBz-3-0Ph with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Amp/Am, [MeAP], 10*4 M [Q], M on
0.494 1.83 0.0000 1.00
0.187 0.69 0.0106 2.64
0.114 0.42 0.0212 4.33
0.079" 0.29 0.0318 6.28
0.067‘ 0.25 0.0424 7.38

 

 

 

 

L kq‘r = 156.0 1 I

 

[Ketone] = 9.9877x10’4 M. [MeBe] = 1.0283x10'3 M. Irradiation for 10.0 h. HPLC
condition set 8. ’Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run2

Amp/AM... [MeAP], 10‘5 M [Q], M two
2.448 11.19 0.0000 1.00

1.236 5.65 0.0067 1.98

0.815 3.73 0.0134 3.00

0.613 2.80 0.0201 3.99

0.484 2.21 0.0267 5.06

l m = 150.7

 

[Ketone] = 9.9877x10‘4 M. [MeBe] = 1.2703x10'3 M. Irradiation for 4.5 h. HPLC
condition set 8. Correlation coefficient = 0.999.

144

Table 22. Stem-Volmer Quenching of the 4-Methy1acetophenone Formation in
MeBz-4—OPh with 2,5-Dimethy1-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Arum/Anna. [MeAP]. 10‘5 M [Q]. M mm
3.538 16.18 0.0000 1.00
0.469 2.14 0.0067 7.55
0.228 1.04 0.0134 15.51
0.158" 0.72 0.0201 22.45
0.101“ 0.46 0.0267 35.06

 

 

 

 

l m = 1177.8 1

[Ketone] = 1.0919x10'3 M. [MeBe] = 1.2704x10'3 M. Irradiation for 4.5 h. HPLC
condition set 1. *Average of 1 tube. Correlation coefficient = 0.991.

 

 

Run 2
map/Am. [MeAP], 10'5 M [Q], M 4)./(D
2.719 8.62 0.0000 1.00
0.443 1.40 0.0053 6.14
0.235 0.75 0.0107 11.55
0.180 0.57 0.0160 15.12
0.1 13‘ 0.36 0.0213 23.98

 

 

 

 

l qu = 1003.3

 

[Ketone] = 0.9987x10'3 M. [MeBe] = 0.8803x10'3 M. Irradiation for 3.0 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.990.

145

Table 23. Stern-Volmer Quenching of the 4-Methylacetophenone Formation in
MeBz-S-OPh with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run]

Anni/An... [MeAP]. 10" M [0]. M 9.19
3.067 9.71 0.0000 1.00

1.202 3.81 0.0053 2.55

0.679" 2.15 0.0107 4.52

0.422‘ 1.34 0.0160 7.28

0.287‘ 0.91 0.0213 10.69

| kq’t = 413.8

 

[Ketone] = 0.9987x10'3 M. [MeBe] = 0.8802x10’3 M. Irradiation for 3.0 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.988.

 

 

 

 

 

 

Run 2

Arum/Arum. [MeAP]. 10'5 M [Q]. M 9.19
2.650 11.26 0.0000 1.00

0.768 3.26 0.0065 3.45

0.420’ 1.79 0.0130 6.30

0.317‘ 1.35 0.0195 8.35

0.216‘ 0.92 0.0260 12.28

qu = 410.9

 

[Ketone] = 0.9420x10’3 M. [MeBe] = 1.1825x10’3 M. Irradiation for 3.0 h. HPLC
condition set 1. *Average of 1 tube. Correlation coefficient = 0.995.

146

Table 24. Stem~Volmer Quenching of the Acetophenone Formation in
Bz-3-0Np with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Arr/An... [AP]. 10" M [Q]. M 9.19
0.903 1.29 0.0000 1.00
0.874 1.26 0.0099 1.03
0.844 1.22 0.0198 1.07
0.805 1.16 0.0296 1.12
0.774“ 1.1 1 ’ 0.0395 1.17

 

 

 

 

k4: = 4.0 1

 

[Ketone] = 1.0447x10'3 M. [MeBe] = 1.0104rt10‘3 M. Irradiation for 14.5 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.995.

 

 

 

 

 

 

Run 2
AAP/AMeBe [AP], 10.5 M [Q], M 9’6“”
0.647 9.31 0.0000 1.00
0.619 8.92 0.0100 1.04
0.606 8.72 0.0201 1.07
0.565 8.14 0.0301 1.14
0.552 7.95 0.0401 1.17
kq'r = 4.3

 

[Ketone] = 1.0309x10'3 M. [MeBe] = 1.0168x10'3 M. Irradiation for 13.0 h. HPLC
condition set 1. Correlation coefficient = 0.987.

147

Table 25. Stem-Volmer Quenching of the Acetophenone Formation in Bz-4-0Np with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Arr/Ana. [AP], 10" M [Q]. M 9.19
0.702 8.99 0.0000 1.00
0.589 7.55 0.0103 1.19
0.518 6.64 0.0207 1.35
0.475 6.09 0.0310 1.48
0.429 5.50 0.0414 1.63

 

 

 

 

1th = 15.7

 

[Ketone] = 0.9623x10'3 M. [MeBe] = 0.8917x10'3 M. Irradiation for 11.0 h. HPLC
condition set 1. Correlation coefficient = 0.997.

 

 

 

 

 

 

Run 2
AAP/AMeBe [AP]. 10'5 M [Q]. M ¢J<I>
0.620 8.58 0.0000 1.00
0.540 7.47 0.0107 1.15
0.448 6.19 0.0214 1.39
0.404 5.59 0.0322 1.54
0.360 4.98 0.0429 1.72
I kqt = 16.8

 

[Ketone] = 0.9594x10’3 M. [MeBe] = 0.9635x10'3 M. Irradiation for 12.0 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.998.

148

Table 26. Stem-Volmer Quenching of the Acetophenone Formation in Bz-S-ONp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Asp/Arms. [AP]. 10" M [Q]. M 9.19
0.497 6.80 0.0000 1.00
0.399 5.46 0.01 14 1.25
0.341" 4.66 0.0228 1.46
0.301 4.1 1 0.0342 1.65
0.262" 3.59 0.0456 1.90

 

 

 

 

L k,,r = 19.6

 

[Ketone] = 0.9171x10’3 M. [MeBe] = 0.9548x10’3 M. Irradiation for 3.2 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run2

Arr/Ana. [AP]. 10" M [Q]. M «MD

0.360 4.93 0.0000 1.00

0.330 4.52 0.0046 1.09

0.307 4.20 0.0092 1.17

0.287 3.93 0.0138 1.26

0.264” 3.61 0.0184 1.37

qu = 19.4

 

[Ketone] = 0.9454x10'3 M. [MeBe] = 0.9548x10’3 M. Irradiation for 4.0 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.998.

 

149

Table 27. Stem-Volmer Quenching of the Acetophenone Formation in Bz-6-0Np with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run I
Arr/An... [AP], 10" M [Q], M 9.19
0.402 5.15 0.0000 1.00
0.317 4.07 0.0103 1.27
0.268 3.44 0.0207 1 .50
0.237 3.04 0.0310 1.69
0.206 2.65 0.0414 1.95

 

 

 

 

kg]: = 22.9

 

[Ketone] = 0.9091x10'3 M. [MeBe] = 0.8917x10'3 M. Irradiation for 2.0 h. HPLC
condition set 1. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run2
Air/Arum. [AP]. 10" M [Q]. M 9.19
0.526 8.71 0.0000 1.00
0.418 6.93 0.0104 1.26
0.362 5.99 0.0207 1.45
0.319 5.28 0.0311 1.65
0.279’ 4.62 0.0414 1.89
kg: = 21.4

 

[Ketone] = 0.9130x10'3 M. [MeBe] = 1.1576x10'3 M. Irradiation for 3.2 h. HPLC
condition set 1. ’Average of 1 tube. Correlation coefficient = 0.999.

 

150

Table 28. Stem-Volmer Quenching of the Acetophenone Formation in Bz-7-0Np with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Asp/Arum. [AP]. 10" M [Q], M 9.19
0.610 10.20 0.0000 1.00
0.497 8.30 0.0104 1.23
0.413 6.89 0.0207 1.48
0.356 5.94 0.031 1 1.72
0.312’ 5.21 0.0415 1.96

 

 

 

 

l kq't = 23.1 1

[Ketone] = 0.9479x10'3 M. [MeBe] = 1.1576x10’3 M. Irradiation for 3.2 h. HPLC
condition set 2. 'Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run2

AAP/AMeBe [AP]. 10" M [Q]. M 9.19

0.371 6.20 0.0000 1.00

0.299 4.99 0.01 14 1.24

0.234“ 3.91 0.0228 1.58

0.208" 3.47 0.0342 1.78

0.181“ 3.03 0.0456 2.05

qu = 23.2

 

[Ketone] = 0.8630x10’3 M. [MeBe] = 1.1576x10'3 M. Irradiation for 3.2 h. HPLC
condition set 2. 'Average of 1 tube. Correlation coefficient = 0.999.

151

Table 29. Stem-Volmer Quenching of the Acetophenone Formation in Bz-9-0Np with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run 1

Arr/Ana. [AP]. 10" M [Q]. M 9.19
0.499 6.54 0.0000 1.00

0.434 5.69 0.0084 1.15

0.385 5.04 0.0167 1.30

0.359" 4.70 0.0251 1.39

0.321 4.20 0.0334 1.56

qu = 16.5

 

[Ketone] = 2.0347x10'3 M. [MeBe] = 0.9166x10'3 M. Irradiation for 6 h. HPLC
condition set 7. 'Average of 1 tube. Correlation coefficient = 0.997.

 

 

 

 

 

 

Run2

AAP/AMene [AP]. 10" M [Q], M <I>J<I>
0.333‘ 4.51 0.0000 1.00

0.294" 3.98 0.0073 1.13

0.283‘ 3.83 0.0146 1.18

0.254 3.43 0.0219 1.31

0.241“ 3.26 0.0292 1.39

hr = 13.6

 

[Ketone] = 1.0307x10'3 M. [MeBe] = 0.9489x10'3 M. Irradiation for 6 h. HPLC
condition set 7. *Average of 1 tube. Correlation coefficient = 0.990.

 

152

Table 30. Stern-Volmer Quenching of the Acetophenone Formation in Bz-lO-ONp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Ari/An... [AP], 10" M [Q]. M 9.19
0.319‘ 4.17 0.0000 1.00
0.285 3.73 0.0059 1.12
0.271‘ 3.55 0.0118 1.18
0.255‘ 3.35 0.0177 1.25
0.236 3.10 0.236 1.35

 

 

 

 

 

l qu = 14.7 I

 

[Ketone] = 1.0244x10’3 M. [MeBe] = 0.9166x10’3 M. Irradiation for 6 h. HPLC
condition set 2. ‘Average of 1 tube. Correlation coefficient = 0.993.

 

 

 

 

 

 

 

 

Run2
AAF/AMeBe [AP]. 10" M [Q]. M 9.19
0.375‘ 5.07 0.0000 1.00
0.340‘ 4.60 0.0073 1.10
0.322” 4.37 0.0146 1.16
0.302‘ 4.08 0.0219 1.24
0.270‘ 3.65 0.0292 1.39
kq’t = 12.4 1

 

[Ketone] = 1.0141x10'3 M. [MeBe] = 0.9490x10'3 M. Irradiation for 6 h. HPLC
condition set 7. 'Average of 1 tube. Correlation coefficient = 0.987.

153

Table 31. Stem-Volmer Quenching of the Acetophenone Formation in Bz-l 1-0Np with
2,5-Dimethyl-2,4—hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

RunI

ran/An... [AP], 10" M [Q]. M 9.!9
0.400 6.34 0.0000 1.00

0.329 5.22 0.0089 1.22

0.279“ 4.42 0.0178 1.44

0242" 3.83 0.0267 1.65

0.21 1" 3.34 0.0356 1.90

hr = 24.9

 

[Ketone] = 1.0764x10'3 M. [MeBe] = 1.0959x10'3 M. Irradiation for 4.0 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run 2
Air/Arum. [AP]. 10'5 M [Q]. M ¢ol¢
0.360 4.92 0.0000 1.00
0.313’ 4.28 0.0049 1.15
0.296 4.05 0.0098 1.22
0.264 3.61 0.0147 1.36
0.243" 3.32 0.0196 1.48
l kqt = 24.5

 

[Ketone] = 1.0242x10'3 M. [MeBe] = 0.9548x10'3 M. Irradiation for 4.0 h. HPLC
condition set 2. 'Average of 1 tube. Correlation coefficient = 0.995.

 

154

Table 32. Stem-Volmer Quenching of the Acetophenone Formation in Bz-l4-0Np with
2,5-Dimethyl—2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

Run]
Arr/An... [AP], 10" M [Q]. M 9.19
0.355 5.11 0.0000 1.00
0.283“ 4.07 0.0066 1.26
0.237 3.41 0.0132 1.50 1
0.215" 3.09 0.0199 1.65 E
0.190 2.73 0.0265 1.87 ‘
kq‘t = 33.8

 

[Ketone] = 0.9986x10’3 M. [MeBe] = 1.0077x10'3 M. Irradiation for 6 h. HPLC
condition set 8. ’Average of 1 tube. Correlation coefficient = 0.996.

 

 

 

 

 

 

Run2
Arr/An... [AP]. 10" M [Q]. M 9.19
0.339 4.88 0.0000 1.00
0.270 3.89 0.0083 1.25
0.235 3.39 0.0167 1.44
0.204 2.95 0.0250 1.66
0.174 2.50 0.0333 1.95
1 kn: = 27.7

 

[Ketone] = 0.9986x10’3 M. [MeBe] = 1.0018x10'3 M. Irradiation for 4 n. HPLC
condition set 7. ‘Average of 1 tube. Correlation coefficient = 0.996.

155

Table 33. Stem—Volmer Quenching of the Acetophenone Formation in Bz-3-O4Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run I
AAP/AMeBe [AP]. 10" M [Q]. M 9.19
0.693 1.06 0.0000 1.00
0.647 0.99 0.0091 1.07
0.597‘ 0.91 0.0181 1.16
0.565 0.86 0.0272 1.23
0.533 0.81 0.0362 1.30

 

 

 

 

l qu = 8.3 I

 

[Ketone] = 103le103 M. [MeBe] = 1.0606x10'3 M. Irradiation for 13 h. HPLC
condition set 1. ’Average of 1 tube. Correlation coefficient = 0.999.

 

 

Run 2
Ari/An... [AP]. 10" M [Q]. M <DJ<I>
0.410 6.15 0.0000 1.00
0.378 5.66 0.0105 1.09
0358* 5.36 0.0210 1.15
0.336‘ 5.04 0.0316 1.22
0.318‘ 4.77 0.0421 1.29

 

 

 

 

L qu = 7.0 1

[Ketone] = 1.0177x10'3 M. [MeBe] = 1.0386x10'3 M. Irradiation for 14 h. HPLC
condition set 1. *Average of 1 tube. Correlation coefficient = 0.999.

“V

 

 

156

Table 34. Stem-Volmer Quenching of the Acetophenone Formation in Bz-4-O4Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run]

Arr/An... [AP]. 10" M [Q]. M 9.19
0.163 2.39 0.0000 1.00

0.133 1.96 0.0123 1.22

0.110‘ 1.61 0.0246 1.48

0.094" 1.38 0.0369 1.73

0.080 1.18 0.0491 2.03

qu = 20.4

 

[Ketone] = 1.0049x10'3 M. [MeBe] = 1.0224x10'3 M. Irradiation for 6 h. HPLC
condition set 1. *Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run 2

Asp/Arum. [AP]. 10" M [Q]. M 9.!9

0.053 0.79 0.0000 1.00

0.045 0.67 0.0105 1.19

0.037 0.55 0.0210 1.44

0.032‘ 0.48 0.0316 1.67

0.028 0.42 0.0421 1.88

qu = 20.9

 

[Ketone] = 0.9988x10'3 M. [MeBe] = 1.0386x10'3 M. Irradiation for 6 h. HPLC
condition set 1. ’Average of 1 tube. Correlation coefficient = 0.999.

157

Table 35. Stem—Volmer Quenching of the Acetophenone Formation in Bz-5-O48p with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
AAP/AMeBe [AP]. 10'5 M [Q]. M (Do/‘1’
0.238 3 .49 0.0000 1.00
0.194 2.85 0.0089 1.22
0.163 2.40 0.0178 1.46
0.139 2.04 0.0267 1.71
0.123 1.80 0.0357 1.93

 

 

 

 

L qu=26.3 1

[Ketone] = 0.9842x10'3 M. [MeBe] = 1.0224x10‘3 M. Irradiation for 3 h. HPLC
condition set 1. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run2

Arr/An... [AP]. 10" M [Q]. M 9.19

0.242 3.63 0.0000 1.00

0.190 2.84 0.0105 1.28

0.151 2.26 0.0210 1.60

0.129‘ 1.92 0.0316 1.89

0.111" 1.66 0.0421 2.19

l qu = 28.2

 

[Ketone] = 0.9987x10'3 M. [MeBe] = 1.0386x10'3 M. Irradiation for 6 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.999.

158

Table 36. Stem-Volmer Quenching of the Acetophenone Formation in Bz-6-O43p with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run]
AAP/AMeBe [AP]. 10" M [Q]. M 9.!9
0.480 7.05 0.0000 1.00
0.351 5.15 0.0123 1.37
0.294" 4.32 0.0246 1.63
0.229‘ 3.36 0.0369 2.10
0.188“ 2.76 0.0491 2.55
qu = 30.2 I

 

[Ketone] = 1.0099x10'3 M. [MeBe] = 1.0224x10'3 M. Irradiation for 6 h. HPLC
condition set 1. "Average of 1 tube. Correlation coefficient = 0.995.

 

 

 

 

 

 

Run2

Aim/An... [AP]. 10" M [Q]. M ¢J¢

0.322 4.63 0.0000 1.00

0.245 3.52 0.0098 1.32

0.191‘ 2.75 0.0196 1.69

0.170“ 2.45 0.0294 1.89

0.149 2.15 0.0392 2.16

kg: = 30.6

 

[Ketone] = 0.9890x10'3 M. [MeBe] = 1.0039x10'3 M. Irradiation for 5 1‘]. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.995.

 

 

159

Table 37. Stem-Volmer Quenching of the Acetophenone Formation in Bz-7-O4Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Air/An... [AP]. 10'5 M [Q]. M 9.19
0.298 4.38 0.0000 1.00
0.237 3.47 0.0089 1.26
0.188 2.77 0.0178 1.58
0.158 2.31 0.0267 1.89 i
0.139‘ 2.03 0.0357 2.15

 

 

 

 

 

qu = 32.6

 

[Ketone] = 1.0014x10'3 M. [MeBe] = 1.0224x10'3 M. Irradiation for 3 h. HPLC
condition set 1. ’Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

 

 

 

 

Run 2
AAP/AMeBe [AP]. 105 M [Q]. M (Po/‘1’
0.368 5.30 0.0000 1.00
0.289 4.17 0.0098 1.27
0.229 3.30 0.0196 1.61
0.189“ 2.72 0.0294 1.95
0.160‘ 2.31 0.0392 2.30
l kg: = 32.3

 

[Ketone] = 1.0293x10'3 M. [MeBe] = 1.0039x10'3 M. Irradiation for 5 h. HPLC
condition set 1. *Average of 1 tube. Correlation coefficient = 0.999.

.a

160

Table 38. Stem-Volmer Quenching of the Acetophenone Formation in Bz-9-O4Bp with
2,5-Dimethy1-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Airy/An... [AP]. 10.. M [Q]. M ¢J¢
0.330 7.23 0.0000 1.00
0.274‘ 5.99 0.0095 1.21
0.240 5.25 0.0190 1.38
0.21 1 4.63 0.0285 1.56
0.181‘ 9.97 0.0380 1.82

 

 

 

 

 

L 1r..r=20.8 1

[Ketone] = 0.9987x10'3 M. [MeBe] = 1.5219x10’3 M. Irradiation for 5 h. HPLC
condition set 1. “Average of 1 tube. Correlation coefficient = 0.997.

 

 

 

 

 

 

 

Run 2

AAIJAMeBe [AP]. 10" M [Q]. M 9.19
0.372 8.15 0.0000 1.00
0.310‘ 6.79 0.0096 1.20 l
0266* 5.83 0.0191 1.40
0.238" 5.20 0.0287 1.57
0.208" 4.56 0.0382 1.79

1 k4 = 20.4

 

[Ketone] = 0.9987x10'3 M. [MeBe] = 1.5219x10'3 M. Irradiation for 5 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.999.

161

Table 39. Stem-Volmer Quenching of the Acetophenone Formation in Bz-lO-O4Bp
with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run]
tin/An... [AP]. 10" M [Q]. M 9.19
0.236 3.47 0.0000 1.00
0193* 2.83 0.0123 1.22
0.156" 2.29 0.0246 1.51 1
0.123“ 1.81 0.0369 1.92 E-
0108* 1.59 0.0491 2.18 j
L kg: = 23.7

 

[Ketone] = 0.9921x10'3 M. [MeBe] = 1.0224x10'3 M. Irradiation for 6 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.995.

 

 

 

 

 

 

 

Run2
Arr/An... [AP]. 10“ M [Q]. M <DJ<I>
0.153 2.38 0.0000 1.00
0.124 1.94 0.0093 1.23
0105* 1.63 0.0186 1.46
0.094 1.46 0.0279 1.62
0.083 1.30 0.0372 1.83
kq‘t = 22.8

 

[Ketone] = 1.0404x10'3 M. [MeBe] = 1.0782x10'3 M. Irradiation for 6 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.998.

162

Table 40. Stem-Volmer Quenching of the Acetophenone Formation in Bz-ll-O4Bp
with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Asp/Am. [AP]. 10" M [Q]. M 9.19
0.626 9.74 0.0000 1.00
0.472 7.35 0.0093 1.33
0.393 6.12 0.0186 1.59
0.319 4.97 0.0279 1.96 L
0.275 4.28 0.0372 2.28

 

 

 

 

 

L a”... 1

[Ketone] = 1.0391x10'3 M. [MeBe] = 1.0782x10'3 M. Irradiation for 6 h. HPLC
condition set 1. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run2
Arr/Arm... [AP]. 10" M [Q]. M 9.19
0.433 6.61 0.0000 1.00
0327* 5.00 0.0091 1.32
0.271 4.14 0.0181 1.60 ”
0.230‘ 3.51 0.0272 1.88
0.199" 3.04 0.0363 2.17
I qu = 32.6

 

[Ketone] = 0.9690x10'3 M. [MeBe] = 1.0606x10'3 M. Irradiation for 6 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.999.

163

Table 41. Stem-Volmer Quenching of the Acetophenone Formation in Bz-l4-O4Bp
with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Benzene.

 

 

 

 

 

 

 

Run]
Air/Arum. [AP]. 10.. M [Q]. M 9.19
0.558 8.04 0.0000 1.00
0.473 6.81 0.0055 1.18
0.434 6.25 0.0109 1.29
0.383 5.51 0.0164 1.46 1
0344* 4.95 0.0219 1.62
I qu = 28.2

 

[Ketone] = 1.0249x10'3 M. [MeBe] = 1.0018x10'3 M. Irradiation for 6 h. HPLC
condition set 1. *Average of 1 tube. Correlation coefficient = 0.997.

 

 

Run 2
Ari/An... [AP]. 10" M 101. M 9.19
0.670 9.64 0.0000 1.00
0.579 8.34 0.0047 1.16
0.534“ 7.69 0.0093 1.25
0.496 7.14 0.0140 1.35
0.425“ 6.12 0.0187 1.57

 

 

 

 

 

1 a”... 1

 

[Ketone] = 1.0198x10'3 M. [MeBe] = 1.0018it10'3 M. Irradiation for 6 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.987.

Table 42. Stem-Volmer Quenching of the Acetophenone Formation in Bz-3—OZBp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
AAP/AMeBe [AP]. 10'5 M [Q]. M 9.19
1.014 14.60 0.0000 1.00
0.904 13.02 0.0098 1.12
0.799 1 1.50 0.0197 1.27
0.743 10.69 0.0295 1.37
0702* 10.10 0.0394 1.44

 

 

 

 

 

 

L qu = 12.00 I

[Ketone] = 1.0170x10’3 M. [MeBe] = 1.0027x10'3 M. Irradiation for 14 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.994.

 

 

 

 

 

 

Run2

Arr/An... [AP]. 10" M 10]. M Q“)
0572* 8.23 0.0000 1.00

0.504 7.26 0.0095 1.13

0463* 6.67 0.1909 1.23

0.428 6.17 0.0286 1.33

0396* 5.70 0.0382 1.44

I qu = 11.8

 

[Ketone] = 0.9987x10'3 M. [MeBe] = 1.0028x10'3 M. Irradiation for 10 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.998.

165

Table 43. Stem-Volmer Quenching of the Acetophenone Formation in Bz-4-02Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run 1

Arr/An... [AP]. 10" M [Q]. M <I>J<l>
0.103 1.30 0.0000 1.00

0.086 1.08 0.0075 1.20

0.066 0.84 0.0149 1.55

0.055 0.70 0.0223 1.87

0050* 0.62 0.0298 2.07

qu = 36.7

 

[Ketone] = 1.0411x10'3 M. [MeBe] = 0.8813x10'3 M. Irradiation for 5 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.995.

 

 

Run 2
Arm/An... [AP]. 10" M [Q]. M <I>J<I>
0.128 1.62 0.0000 1.00
0.106 1.35 0.0071 1.21
0.084 1.06 0.0143 1.53
0073* 0.92 0.0214 1.76
0062* 0.78 0.0286 2.07

 

 

 

 

1 a”... 1

[Ketone] = 1.0411x10'3 M. [MeBe] = 0.8814x10’3 M. Irradiation for 6 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.998.

‘5. o '5

 

L

7—1—
.«Mrtu

1'.

 

166

Table 44. Stem-Volmer Quenching of the Acetophenone Formation in Bz-5-02Bp with
2,5-Dimethyl-2,4—hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run]

Alp/An... [AP]. 10" M [Q]. M 9.19
0.390 5.61 0.0000 1.00

0.311 4.48 0.0077 1.25

0.264 3.80 0.0154 1.47

0222* 3.20 0.0231 1.75

0.196 2.82 0.0308 1.99

qu = 32.2

 

[Ketone] = 1.0043x10'3 M. [MeBe] = 1.0007x10‘3 M. Irradiation for 5 h. HPLC
condition set 1. “Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run 2
Ari/An... [AP]. 10" M [Q]. M ¢J<I>
0.342 4.92 0.0000 1.00
0.251 3.62 0.0093 1.36
0.214 3.08 0.0185 1.60
0.179 2.58 0.0278 1.91
0154* 2.22 0.0371 2.22
qu = 32.9

 

[Ketone] = 1.0099x10'3 M. [MeBe] = 1.0095rt10‘3 M. Irradiation for 5 h. HPLC
condition set 1. ’Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

167

Table 45. Stem-Volmer Quenching of the Acetophenone Formation in Bz-6-02Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
AAP/AMeBe [AP]. 10'5 M [Q]. M ¢J¢
0.272 3.92 0.0000 1.00
0.250 3.60 0.0076 1.09
0.197 2.84 0.0152 1.38
0.173 2.49 0.0227 1.57 E— 1
0.152 2.19 0.0303 1.79

 

 

 

 

 

qu = 25.1 1

[Ketone] = 1.0098x10‘3 M. [MeBe] = 1.0018x10'3 M. Irradiation for 6 h. HPLC
condition set 8. Correlation coefficient = 0.992.

 

 

 

 

 

 

Run2

Arr/Arum. [AP]. 10" M [Q]. M 9J9
0308* 4.44 0.0000 1.00

0269* 3.87 0.0066 1.15

0220* 3.17 0.0131 1.40

0197‘ 2.84 0.0197 1.56

0189* 2.72 0.0262 1.63

M = 26.3

 

[Ketone] = 0.9987x10'3 M. [MeBe] = 0.9960x10'3 M. Irradiation for 7 h. HPLC
condition set 8. 'Average of 1 tube. Correlation coefficient = 0.984.

168

Table 46. Stem-Volmer Quenching of the Acetophenone Formation in Bz-7-02Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

Run 1
Ari/An... [AP]. 10" M [Q]. M 9.19
0.510 7.35 0.0000 1.00
0.438 6.30 0.0091 1.17
0370* 5.32 0.0181 1.38
0.344 4.96 0.0272 1.48 1* -
0276* 3.98 0.0362 1.85
qu = 21.2

 

[Ketone] = 0.9933x10'3 M. [MeBe] = 1.0107x10'3 M. Irradiation for 6 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.982.

 

 

 

 

 

 

 

Run 2

Arr/Aria... [AP]. 10" M [Q]. M 9.19

0.283 3.92 0.0000 1.00

0237* 3.27 0.0086 1.20

0215* 2.97 0.0172 1.32

0175* 2.41 0.0257 1.62

0.163 2.26 0.0343 1.74

I m = 22.0

 

[Ketone] = 0.9896x10'3 M. [MeBe] = 0.9636x10’3 M. Irradiation for 6 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.990.

169

Table 47. Stem—Volmer Quenching of the Acetophenone Formation in Bz-9-O2Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

RunI

Arm/An... [AP]. 10" M [Q]. M 9.19
0.361 4.57 0.0000 1.00

0.300 3.80 0.0071 1.20

0.252 3.19 0.0143 1.43

0.214 2.72 0.0214 1.68

0195* 2.47 0.0286 1.85

qu = 30.5

 

[Ketone] = 1.0136x10’3 M. [MeBe] = 0.8814x10'3 M. Irradiation for 6 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run 2
Ara/An... [AP]. 10" M [Q]. M 9.19
0.397 5.26 0.0000 1.00
0.314 4.16 0.0076 1.26
0.278 3.68 0.0153 1.43
0229* 3.03 0.0229 1.73
0.215 2.85 0.0306 1.84
IQ"! = 29.2

 

[Ketone] = 1.0037rt10‘3 M. [MeBe] = 0.9166x10'3 M. Irradiation for 6 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.992.

I: _ .

 

null

170

Table 48. Stem-Volmer Quenching of the Acetophenone Formation in Bz-10-02Bp
with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run 1
Air/An... [AP]. 10" M [Q]. M 9.19
0.380 5.14 0.0000 1.00
0.329 4.45 0.0061 1.16
0296" 4.00 0.0123 1.28
0267* 3.62 0.0184 1.42
0243* 3.30 0.0245 1.56
kg: = 22.9 I

 

[Ketone] = 1.0131x10'3 M. [MeBe] = 0.9490x10'3 M. Irradiation for 7 h. HPLC
condition set 7. 'Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run 2
AAP/AMcBe [AP]. 105 M [Q]. M ‘po/q’
0.402 5.79 0.0000 1.00
0.329 4.74 0.0070 1.22
0296* 4.26 0.0139 1.36
0269* 3.87 0.0209 1.50
0239* 3.44 0.0278 1.68
qu = 24.7

 

[Ketone] = 1.0035x10'3 M. [MeBe] = 1.0077x10'3 M. Irradiation for 7 h. HPLC
condition set 1. ~‘Average of 1 tube. Correlation coefficient = 0.996.

 

171

Table 49. Stem-Volmer Quenching of the Acetophenone Formation in Bz-l l-O2Bp
with 2,5-Dimethy1-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run 1
Arr/An... [AP]. 10“ M [Q]. M <I>J<I>
0.471 6.37 0.0000 1.00
0.380 5.14 0.0064 1.24
0.316 4.28 0.0127 1.49
0.284 3.84 0.0191 1.66
0.261 3.54 0.0255 1.80
qu = 33.5

 

[Ketone] = 1.0220rt10‘3 M. [MeBe] = 0.9490rt10'3 M. Irradiation for 7 h. HPLC
condition set 1. Correlation coefficient = 0.993.

 

 

 

 

 

 

Run 2

Airy/An... [AP]. 10" M [Q]. M 9.19

0.536 7.72 0.0000 1.00

0.413 5.95 0.0070 1.30

0346* 4.98 0.0139 1.55

0.304 4.37 0.0209 1.76

0261* 3.76 0.0278 2.05

qu = 37.8

 

[Ketone] = 1.0080x10'3 M. [MeBe] = 1.0077x10’3 M. Irradiation for 7 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.999.

 

 

172

Table 50. Stem-Volmer Quenching of the Acetophenone Formation in Bz-l4-O2Bp
with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run I
Arr/Am. [AP]. 10" M [Q]. M 9.19
0.422 6.07 0.0000 1.00
0340* 4.90 0.0060 1.24
0.295 4.25 0.0120 1.43
0.251 3.61 0.0180 1.68
0216* 3.1 1 0.0240 1.95

 

 

 

 

 

r qu = 38.6

 

[Ketone] = 0.9999x10'3 M. [MeBe] = 1.0077x10'3 M. Irradiation for 6 h. HPLC
condition set 8. ’Average of 1 tube. Correlation coefficient = 0.998.

 

 

Run 2
ran/An... [AP]. 10" M [Q]. M 9.19
0.484 6.97 0.0000 1.00
0.346 4.98 0.0083 1.40
0277* 3.99 00167 1.75
0236* 3.40 0.0250 2.05
0218* 3.14 0.0333 2.22

 

 

 

 

 

L qu = 39.8

[Ketone] = 1.0113x10’3 M. [MeBe] = 1.0018x10'3 M. Irradiation for 6 h. HPLC
condition set 8. ‘Average of 1 tube. Correlation coefficient = 0.990.

173

Table 51. Stem-Volmer Quenching of the Acetophenone Formation in Bz-3-O3Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

Run 1
Arr/Anna [AP]. 10" M [Q]. M 9J9
0.802 1 1.55 0.0000 1.00
0726* 10.45 0.0098 1.11
0.677 9.75 0.0197 1.18
0612* 8.82 0.0295 1.31 I.
0569* 8.19 0.0394 1.41 I
- 1?.

 

qu = 10.3 1

[Ketone] = 1.0138x10'3 M. [MeBe] = 1.0027x10'3 M. Irradiation for 14 h. HPLC
condition set 1. *Average of 1 tube. Correlation coefficient = 0.998.

 

 

Run 2
AAF/AMeBe [AP]. 10" M [Q]. M 9.!9
0.498 7.17 0.0000 1.00
0.476 6.85 0.0095 1.05
0.424 6.11 0.0191 1.18
0.386 5.55 0.0286 1.29
0357* 5.14 0.0382 1.40

 

 

 

 

L qu = 10.0

[Ketone] = 0.9987x10'3 M. [MeBe] = 1.0028rt10'3 M. Irradiation for 10 h. HPLC
condition set 1. ’Average of 1 tube. Correlation coefficient = 0.992.

174

Table 52. Stem-Volmer Quenching of the Acetophenone Formation in Bz-6-O3Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run 1
Ann/Am. [AP]. 10" M [Q]. M 9.19
0.337 4.85 0.0000 1.00
0.269 3.87 0.0076 1.25
0.217 3.12 0.0152 1.55
0.196 2.83 0.0227 1.71
0170* 2.45 0.0303 1.98
qu = 32.6 I

 

[Ketone] = 0.9987x10’3 M. [MeBe] = 1.0018rt10'3 M. Irradiation for 6 h. HPLC
condition set 8. 'Average of 1 tube. Correlation coefficient = 0.997.

 

 

 

 

 

 

Run2

Arr/An... [AP]. 10" M [Q]. M 9.19

0.41 1 5.91 0.0000 1.00

0.340 4.90 0.0066 1.21

0.290 4.18 0.0131 1.42

0.239 3.45 0.0197 1.72

0225* 3.23 0.0262 1.83

kg: = 33.1

 

[Ketone] = 0.9931x10'3 M. [MeBe] = 0.9960x10'3 M. Irradiation for 7 h. HPLC
condition set 8. 'Average of 1 tube. Correlation coefficient = 0.993.

175

Table 53. Stem-Volmer Quenching of the Acetophenone Formation in Bz-7—O3Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
Arr/Arum. [AP]. 10'5 M IO]. M 9.19
0.646 9.31 0.0000 1.00
0.505 7.28 0.0091 1.28
0404* 5.81 0.0181 1.60
0369* 5.32 0.0272 1.75
0333* 4.80 0.0362 1.94

 

 

 

 

qu = 27.5 I

 

[Ketone] = 0.9933x10'3 M. [MeBe] = 1.0007x10'3 M. Irradiation for 6 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.989.

 

 

 

 

 

 

Run2

AAP/AMeBe [AP]. 10" M [Q]. M 9.19

0.406 5.61 0.0000 1.00

0.322 4.44 0.0086 1.26

0.275 3.80 0.0172 1.48

0241* 3.34 0.0257 1.68

0208* 2.88 0.0343 1.95

I kg“: = 27.4

 

[Ketone] = 1.0041rt10'3 M. [MeBe] = 0.9636x10’3 M. Irradiation for 6 h. HPLC
condition set 1. 'Average of 1 tube. Correlation coefficient = 0.999.

176

Table 54. Stem-Volmer Quenching of the Acetophenone Formation in Bz-9-O3Bp with
2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

Ari/An... [AP]. 10" M [Q]. M 9.19
0.270 3.89 0.0000 1.00
0.223 3.21 0.0065 1.21
0.180 2.60 0.0129 1.50

0168* 2.42 0.0194 1.61 1 .
0136* 1.96 0.0258 1.99
kg“: = 36.1

 

[Ketone] = 1.0087x10'3 M. [MeBe] = 0.9960x10'3 M. Irradiation for 6 h. HPLC
condition set 10. 'Average of 1 tube. Correlation coefficient = 0.989.

 

177

Table 55. Stem-Volmer Quenching of the Acetophenone Formation in Bz-10-03Bp
with 2,5-Dimethyl-2,4—hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

Run]
Air/An... [AP]. 10" M [Q]. M <DJ<I>
0.336 4.84 0.0000 1.00
0.293 4.23 0.0065 1.15
0.250 3.61 0.0129 1.34
0211* 3.04 0.0194 1.59 i- a
0193* 2.78 0.0258 1.74
k.,1: = 28.7

 

[Ketone] = 0.9987x10'3 M. [MeBe] -.= 0.9960x10‘3 M. Irradiation for 6 h. HPLC
condition set 10. 'Average of 1 tube. Correlation coefficient = 0.996.

 

 

 

 

 

 

 

Run 2
AAP/AMeBe [AP]. 10'5 M [Q]. M ‘PJ‘P
0.313 4.51 0.0000 1.00
0.262 3.78 0.0065 1.19
0224* 3.23 0.0130 1.40
0.201 2.90 0.0194 1.56
0182* 2.62 0.0259 1.72
k,,r = 28.5

 

[Ketone] = 1.0035x10’3 M. [MeBe] = 0.9960x10‘3 M. Irradiation for 6 h. HPLC
condition set 10. 'Average of 1 tube. Correlation coefficient = 0.999.

178

Table 56. Stem-Volmer Quenching of the Acetophenone Formation in Bz-14-03Bp
with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

Run I
AAP/AMeBe [AP]. 10" M [Q]. M 9.!9
0.303 4.37 0.0000 1.00
0.238 3.42 0.0065 1.28
0.204 2.93 0.0130 1.49 E
0183* 2.64 0.0194 1.66 1‘ -.—-
0155* 2.23 0.0259 1.96

 

 

 

 

 

qu = 36.3 I

 

[Ketone] = 0.9985x10'3 M. [MeBe] = 0.9960x10'3 M. Irradiation for 6 h. HPLC
condition set 8. 'Average of 1 tube. Correlation coefficient = 0.996.

 

 

 

 

 

 

 

Run2
Arr/An... [AP]. 10" M [Q]. M ‘ 9.19
0.310 4.46 0.0000 1.00
0.263 3.78 0.0062 1.18
0.217 3.12 0.0123 1.43
0.194 5 2.79 0.0185 1.60
0162* 2.33 0.0246 1.92
qu = 35.2 I

 

[Ketone] = 1.0028x10'3 M. [MeBe] = 1.0042x10'3 M. Irradiation for 6 h. HPLC
condition set 8. .Average of 1 tube. Correlation coefficient = 0.994.

179

Table 57. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in
MeBz-3-0Np with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run 1
Anny/An... 1MeAP1.10“‘M [Q]. M <I>J<I>
0.312 1.37 0.0000 1.00
0.302 1.33 0.0099 1.03
0292* 1.28 0.0198 1.07
0.285 1.25 0.0296 1.10
0275* 1.21 0.0352 1.14
qu = 3.4

 

[Ketone] = 1.0347x10'3 M. [MeBe] = 1.0104x10'3 M. Irradiation for 48 h. HPLC
condition set 1. ‘Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run2
Amp/AM... [MeAP], 10'5 M [Q], M 9.19
0.192 8.44 0.0000 1.00
0.186 8.18 0.0100 1.03
0.181 7.97 0.0200 1.06
0.174 7.64 0.0301 1.10
0169* 7.45 0.0401 1.13
kq'c = 3.3 I

 

[Ketone] = 1.0201x10'3 M. [MeBe] = 1.0168x10'3 M. Irradiation for 44 h. HPLC
condition set 2. ’Average of 1 tube. Correlation coefficient = 0.997.

I imam-.4 “a."

 

 

180

Table 58. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in
MeBz-4-0Np with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run 1

Amp/AM... [MeAP], 10" M [Q], M 9.19
0.289 1.44 0.0000 1.00

0.264 1.31 0.0092 1.09

0.225 1.12 0.0185 1.29

0.204 1.01 0.0277 1.42

0182* 0.90 0.0369 1.59

I m = 15.5

 

[Ketone] = 0.9611x10’3 M. [MeBe] = 1.1311x10'3 M. Irradiation for 88 h. HPLC
condition set 3. *Average of 1 tube. Correlation coefficient = 0.996.

 

 

 

 

 

 

Run 2
Amp/AM... [MeAP], 10" M [Q], M 9.19
0.280 1.18 0.0000 1.00
0232* 0.98 0.1014 1.20
0.212 0.89 0.0203 1.32
0188* 0.80 0.0304 1.49
0171* 0.72 0.0406 1.63
10,1 = 15.9

 

[Ketone] = 1.0578x10'3 M. [MeBe] = 0.9635x10’3 M. Irradiation for 68 h. HPLC
condition set 6. ’Average of 1 tube. Correlation coefficient = 0.997.

 

 

181

Table 59. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in
MeBz-S-ONp with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

Run 1
Amp/AM... [MeAP], 10“ M [Q], M 9,19
0.328 1.54 0.0000 1.00
0.268 1.26 0.0097 1.22
0.236 1.11 0.0194 1.39
0.236 0.99 0.0291 1.56 . ..—
0.181 0.85 0.0388 1.81
qu = 20.3

 

[Ketone] = 1.0469x10'3 M. [MeBe] = 1065411103 M. Irradiation for 65.5 h. HPLC
condition set 6. Correlation coefficient = 0.997.

 

 

 

Run 2
Amp/AM... [MeAP], 10“ M [Q], M 9.19
0.417 1.89 0.0000 1.00
0.346 1.57 0.0109 1.20 L
0.314 1.42 0.0217 1.33
0.245 1.11 0.0326 1.70 ._
0.219 0.99 0.0435 1.90 1

 

 

 

 

 

L qu = 20.2 I

[Ketone] = 1.2562x10’3 M. [MeBe] = 1.0283x10’3 M. Irradiation for 41 h. HPLC
condition set 6. Correlation coefficient = 0.988.

182

Table 60. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in
MeBz-6-0Np with 2,5-Dimethyl-2,4—hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run 1

Amp/AM... [MeAP], 10“ M [Q], M 9.19
0.350 1.90 0.0000 1.00

0.270 1.46 0.0099 1.30

0.237 1.28 0.0199 1.48

0.196 1.06 0.0298 1.79

0.184 1.00 0.0397 1.90

kg = 24.3

 

[Ketone] = 1.0189x10'3 M. [MeBe] = 1.2281x10'3 M. Irradiation for 42 h. HPLC
condition set 6. Correlation coefficient = 0.991.

 

 

 

 

 

 

Run 2
Amp/AM... [MeAP], 10“ M [Q], M 9.19
0.448 1.39 0.0000 1.00
0.369 1.14 0.0096 1.21
0.322 0.98 0.0191 1.39
0.280 0.87 0.0287 1.60
0.229 0.71 0.0383 1.96
kg: = 23.1

 

[Ketone] = 1.0160x10'3 M. [MeBe] = 0.9607x10'3 M. Irradiation for 45 h. HPLC
condition set 4. Correlation coefficient = 0.990.

 

 

183

Table 61. Stem-Volmer Quenching of the 4-Methy1acetophenone Formation in
MeBz-7-0Np with 2,5-Dimethy1-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run I
Arum/An... 1MeAP1.10°‘M [Q].M 9.19
0.635 1.97 0.0000 1.00
0.489 1.52 0.0096 1.30
0.418 1.30 0.0191 1.52
0.37 8 1.17 0.0287 1.68
0.330 1.02 0.0383 1.93
kg: = 24.7

 

[Ketone] = 0.9931x10’3 M. [MeBe] = 0.9607x10'3 M. Irradiation for 45 h. HPLC
condition set 6. Correlation coefficient = 0.995.

 

 

 

 

 

 

Run 2
111......IAM.Be [MeAP], 10“ M [Q], M 9.19
0.675 1.99 0.0000 1.00
0.528 1.55 0.0097 1.28
0.453 1.33 0.0195 1.49
0.371 1.09 0.0292 1.82
0.332 0.98 0.0390 2.04
kq‘t = 26.9

 

[Ketone] = 0.9709x10'3 M. [MeBe] = 0.9078x10’3 M. Irradiation for 27 h. HPLC
condition set 6. Correlation coefficient = 0.998.

 

 

184

Table 62. Stem-Volmer Quenching of the 4-Methylacetophenone Formation in
MeBz-l l-ONp with 2,5-Dimethyl-2,4—hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

Run 1
AMeAP/AMeBe [MeAP], 10.4 M [Q]. M 4’6“!)
0.475 1.40 0.0000 1.00
0.372 1.09 0.0097 1.28
0299* 0.88 0.0195 1.59
0252* 0.74 0.0292 1.88
0217* 0.64 0.0390 2.19
qu = 30.4

 

[Ketone] = 0.9554x10‘3 M. [MeBe] = 0.9078x10'3 M. Irradiation for 17 h. HPLC
condition set 3. *Average of 1 tube. Correlation coefficient = 0.999.

 

 

 

 

 

 

Run2

Amy“... [MeAP], 10“1 M [Q], M 9.19
0.521 2.21 0.0000 1.00

0.419 1.78 0.0101 1.25

0333* 1.41 0.0203 1.57

0.285 1.21 0.0304 1.83

0248* 1.05 0.0406 2.10

‘ qu = 27.2

 

[Ketone] = 0.9525x10'3 M. [MeBe] = 0.9635x10’3 M. Irradiation for 20 h. HPLC
condition set 6. ‘Average of 1 tube. Correlation coefficient = 0.999.

 

 

185

Table 63. Stem—Volmer Quenching of the 4-Methylacetophenone Formation in
MeBz-3-O4Bp with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

Run 1
AMeAP/AMeBe [MCAP]. 10'4 M [Q]. M 4)./4’
0.293 1.29 0.0000 1.00
0.272 1.20 0.0099 1.08
0.245 1.08 0.0198 1.19
0230* 1.01 0.0296 1.27
0.220 0.97 0.0395 . 1.33

 

 

 

 

L qu = 8.8

[Ketone] = 0.9850x10’3 M. [MeBe] = 1.0104x10'3 M. Irradiation for 44 h. HPLC
condition set 5. ’Average of 1 tube. Correlation coefficient = 0.994.

 

 

 

 

 

 

Run 2
Anna/An... [MeAP]. 10" M 10]. M 9.19
0.199 8.77 0.0000 1.00
0.184 8.10 0.0100 1.08
0.172 7.57 0.0200 1.16
0.158 6.97 0.0301 1.26
0.144 6.33 0.0401 1.39
qu = 90

 

[Ketone] = 1.0275x10’3 M. [MeBe] = 1.0104x10'3 M. Irradiation for 47 h. HPLC
condition set 4. 'Average of 1 tube. Correlation coefficient = 0.994.

 

 

186

Table 64. Stem-Volmer Quenching of the Acetophenone Formation in Bz-3-O-2-O4Bp
with 2,5-Dimethyl-2,4-hexadiene at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

Run 1
AAP/AMeBc [AP]. 10" M [Q]. M 9.19
0.307 4.43 0.0000 1.00
0.279 4.01 0.0077 1.10
0267* 3.84 0.0154 1.15
0255* 3.67 0.0231 1.21 I a.
0.237 3.42 0.0308 1.30 f
I kq‘t = 9.6 .

 

[Ketone] = 0.9988x10'3 M. [MeBe] = 1.0106x10’3 M. Irradiation for 5 h. HPLC
condition set 9. *Average of 1 tube. Correlation coefficient = 0.991.

 

 

 

 

 

 

 

Run2
Ara/An... [AP]. 10" M IO]. M 9.19
0.284 4.08 0.0000 1.00
0.252 3.63 0.0093 1.13
0.228 3.28 0.0185 1.25
0217* 3.13 0.0278 1.31
0201* 2.89 0.0371 1.41
qu = 11.5 I

 

[Ketone] = 1.0155x10'3 M. [MeBe] = 1.0194x10'3 M. Irradiation for 5 h. HPLC
condition set 9. ‘Average of 1 tube. Correlation coefficient = 0.995.

187

4.4.9 Quantum Yields Measurements

The quantum yields for product formation were measured by irradiating 0.001M
ketone solutions parallel to 0.001M solutions of valerophenone actinometer in sealed,
degassed tubes. In those measurements, the same procedures were used as described in
the previous paragraphs.

Quantum yields were calculated from the equation

(I) = [P] / I0 (Equation 12)
where [P] is the concentration of photoproduct and I0 is the intensity of light absorbed by
the sample. The value of IO was determined by parallel irradiation of the actinometer (<1)

= 0.3).73 The intensity of light, 10, can be then calculated by

IO = [P] /0.3 (Equation 13)

For irradiations at 366 nm, due to the low molar absorptivity coefficients of the
actinometer and bichromophores, not all light was absorbed by the samples and
corrections were made to compensate for light absorption differences. These corrections

were made with the following equation:

Icorr = Io - ( 1"lo"°)bichromophore / (1‘10-A)actinometer (Equation 14)

where Icon is the corrected intensity of light and A is optical density. All quantum yields

were corrected.

 

 

188

Table 65. Quantum Yields of the Acetophenone Formation in Bz-3-0Ph with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 0.9995x10'3 M. [MeBe] = 4.8182x104 M. [Valerophenone]

 

Run AAP/AMeBe [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10.5 M (Valerophenone) 10.5 M
1 1.521 10.55 1.589 11.02 0.44
2 1.259 9.77 1.306 10.14 0.45
Average Quantum Yield = 0.45

 

1.0232x10'3 M. Irradiation for 4 h. HPLC condition set 8.

Run 2: [Ketone] = 0.9995x10'3 M. [MeBe] = 5.3911x10'4 M. [Valerophenone]

0.9961x10'3 M. Irradiation for 4 h. HPLC condition set 8.

Table 66. Quantum Yields of the Acetophenone Formation in Bz-4-0Ph with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 1.0034rt10'3 M. [MeBe] = 4.818200“1 M. [Valerophenone]

 

Run AAP/AMeBe [AP]. AAP/AMene [AP]. ‘9
(Ketone) 10" M (Valerophenone) 10'5 M
1 2.106 14.61 1.589 11.02 0.42
2 1.849 14.35 1.306 10.14 0.45
Average Quantum Yield = 0.44

 

1.0232x10'3 M. Irradiation for 4 h. HPLC condition set 8.

Run 2: [Ketone] = 0.9837x10'3 M. [MeBe] = 5.3911x10“1 M. [Valerophenone]

0.9961 x10’3 M. Irradiation for 4 h. HPLC condition set 8.

 

 

 

189

Table 67. Quantum Yields of the Acetophenone Formation in Bz-S-OPh with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 1.0069x10‘3 M. [MeBe] = 4.8182x104 M. [Valerophenone]

 

Run AAF’AMeBe [AP 19 AAP/AMeBe [AP], 4)
(Ketone) 10" M (filerophenone) 10'5 M
1 1.814 12.59 1.589 11.02 0.34
2 1.581 12.27 1.306 10.14 0.36
Average Quantum Yield = 0.35

 

1.0232x10'3 M. Irradiation for 4 h. HPLC condition set 8.

Run 2: [Ketone] = 1.0069x10‘3 M. [MeBe] = 5.3911x10'4 M. [Valerophenone]

0.9961x10'3 M. Irradiation for 4 h. HPLC condition set 8.

Table 68. Quantum Yields of the Acetophenone Formation in Bz-7-0Ph with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 0.9960x10’3 M. [MeBe] = 4.8182x104 M. [Valerophenone]

 

Run AAP/AMeBe [AP 19 AAF/AMeBe [AP], (I)
(Ketone) 10‘5 M (Valerophenone) 10'5 M
1 1.581 10.97 1.589 11.02 0.29
2 1.308 10.15 1.306 10.14 0.29
Average Quantum Yield = 0.29

 

1.0232x10‘3 M. Irradiation for 4 h. HPLC condition set 8.

Run 2: [Ketone] = 10129x10'3 M. [MeBe] = 5.3911x10'4 M. [Valerophenone]

0.9961x10'3 M. Irradiation for 4 h. HPLC condition set 8.

 

sit-H
l.1

 

190

Table 69. Quantum Yields of the Acetophenone Formation in Bz-lO-OPh with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBe [AP]. AAP/AMeBc [AP]. 9’
(Ketone) 10'5 M (Valerophenone) 10.5 M
1 1 494 10 37 1.589 11 02 0 27
2 1 148 8 91 1.306 1014 0 25

 

 

 

 

 

 

 

 

 

 

L Average Quantum Yield = 0.26

 

Run 1: [Ketone] = 1.0200x10'3 M. [MeBe] = 4.8182x10‘4 M. [Valerophenone]
1.0232x10’3 M. Irradiation for 4 h. HPLC condition set 8.

Run 2: [Ketone] = 10052x10’3 M. [MeBe] = 5.3911x10'4 M. [Valerophenone]
0.9961x10’3 M. Irradiation for 4 h. HPLC condition set 8.

 

Table 70. Quantum Yields of the Acetophenone Formation in Bz-ll-OPh with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBe [AP], AAP/AMeBe [AP], (I)
(Ketone) 10.5 M (Valerophenone) 10'5 M
1 1 489 10 33 1.589 11 02 0 27
2 l 162 9 02 1.306 1014 0 26

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.26

 

 

Run 1: [Ketone] = 0.9960x10'3 M. [MeBe] = 4.8182x10“1 M. [Valerophenone]
1.0232x10'3 M. Irradiation for 4 h. HPLC condition set 8.

Run 2: [Ketone] = 1.0129x10'3 M. [MeBe] = 5.3911x10'4 M. [Valerophenone]
0.9961x10'3 M. Irradiation for 4 h. HPLC condition set 8.

191

Table 71. Quantum Yields of the Acetophenone Formation in Bz—3-O-2-0Ph with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 1.0165x10'3 M. [MeBe] = 0.9725x10’3 M. [Valerophenone]

 

 

Run AAP/AMeBc [AP]. AAr/AMch [AP]. 9’
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0.653 9.15 0.531 7.4-4 0.45
2 0.744 9.44 0.650 8.25 0.42
Average Quantum Yield = 0.44

 

0.9937x10'3 M. Irradiation for 4 h. HPLC condition set 1.

Run 2: [Ketone] = 0.9741x10'3 M. [MeBe] = 0.8814x10'3 M. [Valerophenone]

1.0048x10’3 M. Irradiation for 5 h. HPLC condition set 1.

Table 72. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-3-0Ph
with Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 1.0224x10'3 M. [MeBe] = 08873x10'3 M. [Valerophenone]

 

Run AMeAP/AMcBe [MeAP], AAP/AMenc [AP]. (P
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 2.490 7 .95 0.477 6.09 0.65
2 2.185 7.35 0.439 6.39 0.57
Average Quantum Yield = 0.61

 

1.0060rt10'3 M. Irradiation for 3 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0811x10'3 M. [MeBe] = 1.0107x10'3 M. [Valerophenone]

1.0109x10'3 M. Irradiation for 3 h. HPLC condition set 1.

'l—’_

 

Haj w

 

 

Table 73. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-4-0Ph

192

with Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 0.9987 x10'3 M. [MeBe] = 0.8873x10‘3 M. [Valerophenone]

 

Run AMeAP/AMch [MeAP]. AAP’AMeBe [AP]. (D
(Ketone) 10.5 M (Valerophenone) 10'5 M
1 2.958 9.45 0.477 6.09 0.55
L———. ————————————————————————————————————————————————
2 3.042 10.43 0.439 6.39 0.57
Average Quantum Yield = 0.56

 

1.0060x10’3 M. Irradiation for 3 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0609x10’3 M. [MeBe] = 1.0107x10'3 M. [Valerophenone]

1.0109x10’3 M. Irradiation for 3 h. HPLC condition set 1.

Table 74. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-S-OPh
with Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

 

Run AMeAP/AMeBe [MCAP]. AAP/AMeBe [AP]. 9’
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 3.067 9.80 0.477 6.09 0.47
2 2547* 8.58 0.439 6.39 0.40
Average Quantum Yield = 0.43

 

Run I : [Ketone] = 0.99869x10'3 M. [MeBe] = 0.8873x10'3 M. [Valerophenone]
1.0060x10'3 M. Irradiation for 3 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0801x10'3 M. [MeBe] = 1.0107x10‘3 M. [Valerophenone]
1.0109x10'3 M. Irradiation for 3 h. HPLC condition set 1.

*Average of 2 tubes.

 

193

Table 75. Quantum Yields of the Acetophenone Formation in Bz-3-0Np with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBc [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0420 401 1.526 1458 013
2 0366 350 1.410 1347 012

 

 

 

 

 

 

 

 

 

L Average Quantum Yield = 0.13

 

Run 1: [Ketone] = 1.0340rt10'3 M. [MeBe] = 0.6636x10'3 M. [Valerophenone] =
1.0232x10’3 M. Irradiation for 4 h. HPLC condition set 1.

 

Run 2: [Ketone] = 1.0000x10'3 M. [MeBe] = 0.6636x10’3 M. [Valerophenone] =
0.9612x10'3 M. Irradiation for 4 h. HPLC condition set 1.

Table 76. Quantum Yields of the Acetophenone Formation in Bz-4-0Np with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAPIAMeBc [AP]. AAP/AMch [AP]. 4’
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0012 167 0.101 14 05 003
2 0 076 1 06 0.585 8 16 0 04

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.04

 

 

Run 1: [Ketone] = 0.9856x10'3 M. [MeBe] = 1.0870x10’3 M. [Valerophenone]
09986rt10'3 M. Irradiation for 4 h. HPLC condition set 6.

Run 2: [Ketone] = 1.0185rt10'3 M. [MeBe] = 1.0900x10'3 M. [Valerophenone]
1.0084x10'3 M. Irradiation for 4 h. HPLC condition set 7.

194

Table 77. Quantum Yields of the Acetophenone Formation in Bz-S-ONp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBe [AP]. AAP/AMch [AP]. ‘3
(Ketone) 10.5 M (Valerophenone) 10'5 M
1 0053 7 37 0.101 1405 015
2 0321 448 0.585 816 016

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.16 I

 

Run 1: [Ketone] = 1.0050x10'3 M. [MeBe] = 1.0870x10'3 M. [Valerophenone]
0.9986x10'3 M. Irradiation for 4 h. HPLC condition set 6.

 

Run 2: [Ketone] = 1.0365x10'3 M. [MeBe] = 1.0900x10’3 M. [Valerophenone]
1.0084x10'3 M. Irradiation for 4 h. HPLC condition set 7.

Table 78. Quantum Yields of the Acetophenone Formation in Bz-6-ONp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBe [AP]. AAr/AMcBe [AP]. 4’
(Ketone) 10'5 M (Valerophenone) 10‘5 M
1 0056 779 0.101 14 05 016
2 0317 442 0.585 816 015

 

 

 

 

 

 

 

 

 

I Average Quantum Yield = 0.16

 

 

Run 1: [Ketone] = 0.9927x10'3 M. [MeBe] = 1.0870rt10‘3 M. [Valerophenone]
0.9986x10'3 M. Irradiation for 4 h. HPLC condition set 6.

Run 2: [Ketone] = 0.9927x10'3 M. [MeBe] = 1.0900x10'3 M. [Valerophenone]
1.0084x10'3 M. Irradiation for 4 h. HPLC condition set 7.

195

Table 79. Quantum Yields of the Acetophenone Formation in Bz-7-0Np with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

 

Run AAP/AMeBe [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10'5 M (Valerophenone) 10" M

1 0.058 8.07 0.101 14.05 0.17

2 0334* 4.66 0.585 8.16 0.17

Average Quantum Yield = 0.17

 

Run 1: [Ketone] = 0.9814x10'3 M. [MeBe] = 1.0870x10’3 M. [Valerophenone]
0.9986x10'3 M. Irradiation for 4 h. HPLC condition set 6.

Run 2: [Ketone] = 1.0103x10’3 M. [MeBe] = 1.0900x10‘3 M. [ValerOphenone]
1.0084rt10'3 M. Irradiation for 4 h. HPLC condition set 7.
'Average of 2 tubes.

Table 80. Quantum Yields of the Acetophenone Formation in Bz-9-0Np with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 2.0347x10'3 M. [MeBe] = 0.9166x10’3 M. [Valerophenone]

 

Run AAP’AMeBe [AP], AAP/AMeBe [AP], 4)
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0.250 3.30 0.785 10.36 0.09
2 0.333 4.55 0.760 10.39 0.13
Average Quantum Yield = 0.11 I

 

1.0048rt10‘3 M. Irradiation for 6 h. HPLC condition set 7.

Run 2: [Ketone] = 1.0307x10‘3 M. [MeBe] = 09490x10'3 M. [Valerophenone]

0.9961x10‘3 M. Irradiation for 6 h. HPLC condition set 7.

 

 

196

Table 81. Quantum Yields of the Acetophenone Formation in Bz-lO-ONp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

Run AAP/AMeBe [AP]. AAP/AMeBe [AP]. ‘1’
(Ketone) 10" M (Valerophenone) 10'5 M
1 0319 421 0.785 10 36 012
2 I 0375* 512 0760 10 39 014

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.13

 

Run I : [Ketone] = 1.0244x10'3 M. [MeBe] = 0.9166x10'3 M. [Valerophenone]
1.0048x10'3 M. Irradiation for 6 h. HPLC condition set 7.

 

Run 2: [Ketone] = 1.0142x10'3 M. [MeBe] = 09490x10'3 M. [Valerophenone]
0.9961x10’3 M. Irradiation for 6 h. HPLC condition set 7.
*Average of 2 tubes.

Table 82. Quantum Yields of the Acetophenone Formation in Bz-l 1-ONp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBe [AP 19 AAP/AMeBe [AP], (I)
(Ketone) 10" M (Valerophenone) 10'5 M
1 0 060 8 35 0.101 14 05 017
2 0371 582 ' 0.585 918 018

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.18

 

 

Run 1: [Ketone] = 1.0192x10'3 M. [MeBe] = 1.0870x10'3 M. [Valerophenone]
0.9986x10'3 M. Irradiation for 4 h. HPLC condition set 6.

Run 2: [Ketone] = 1.0193x10'3 M. [MeBe] = 1.0900x10'3 M. [Valerophenone]
1.0084x10'3 M. Irradiation for 4 h. HPLC condition set 7.

197

Table 83. Quantum Yields of the Acetophenone Formation in Bz-l4-0Np with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

Run AAP/AMeBe [AP]. AAP/AMcBe [AP]. 4’
(Ketone) 10'5 M (Valerophenone) 10.5 M
1 0 355 5 15 0.647 9 39 0 16
2 0 339 4 89 0.675 9 74 0 15

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.15

 

 

Run 1: [Ketone] = 09986x10'3 M. [MeBe] = 1.0077rt10'3 M. [Valerophenone]
1.0109x10'3 M. Irradiation for 6 h. HPLC condition set 8.

 

Run 2: [Ketone] = 0.9986x10’3 M. [MeBe] = 1.0018x10’3 M. [Valerophenone]
0.9996x10'3 M. Irradiation for 6h. HPLC condition set 8.

Table 84. Quantum Yields of the Acetophenone Formation in Bz-3-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBe [AP]. AAP/AMenc [AP]. ‘1’
(Ketone) 10.5 M (Valerophenone) 10'5 M
1 0 367 5 92 0.945 15 25 0 19
2 0 336 514 1.072 16 40 015

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.17

 

 

Run 1: [Ketone] = 1.0122x10'3 M. [MeBe] = 1.1208x10‘3 M. [Valerophenone]
1.0553x10'3 M. Irradiation for 6 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0121x10'3 M. [MeBe] = 1.0621x10'3 M. [Valerophenone]
1.0171rt10'3 M. Irradiation for 6 h. HPLC condition set 1.

198

Table 85. Quantum Yields of the Acetophenone Formation in Bz-4-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAr/AMch [AP]. AAP/AMeBe [AP]. (1)
(Ketone) 10.5 M (ValeroLhenone) 10'5 M
1 0 158 2 55 0.945 15 25 0 05
2 0179 2 74 1.072 1640 005

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.05 I

 

Run 1: [Ketone] = 1.0298x10'3 M. [MeBe] = 1.1208x10'3 M. [Valerophenone]
1.0553x10'3 M. Irradiation for 6 h. HPLC condition set 1.

Run 2: [Ketone] = 0.9995x10'3 M. [MeBe] = 1.0621x10’3 M. [Valerophenone]
1.0171x10'3 M. Irradiation for 6 h. HPLC condition set 1.

Table 86. Quantum Yields of the Acetophenone Formation in Bz-5-O43p with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

Run AAP/AMeBe [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10.5 M (Valerophenone) 10'5 M
1 0 394 6 36 0.945 15 25 0 12
2 0471 720 1.072 1640 013

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.13

 

Run 1: [Ketone] = 1.0169 x103 M. [MeBe] = 1.1208x10'3 M. [Valerophenone] -
1.0553rt10'3 M. Irradiation for 6 h. HPLC condition set 1.

Run 2: [Ketone] = 0.9879 x10'3 M. [MeBe] = 1.0621x10'3 M. [Valerophenone]
1.017lx10'3 M. Irradiation for 6 h. HPLC condition set 1.

 

 

199

Table 87. Quantum Yields of the Acetophenone Formation in Bz-6-04Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBe [AP]. Any/Anew [AP]. (D
(Ketone) 10.5 M (Valerophenone) 10'5 M
1 0 423 6 83 0.945 15 25 0 l3
2 0531 812 1.072 1640 015

 

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.14

 

Run 1: [Ketone] = 1.0330x10‘3 M. [MeBe] = 1.1208x10'3 M. [Valerophenone]
1.0553rt10'3 M. Irradiation for 6 h. HPLC condition set 1.

 

Run 2: [Ketone] = 1.0051x10'3 M. [MeBe] = 1.0621x10'3 M. [Valerophenone]
1.0171x10'3 M. Irradiation for 6 h. HPLC condition set 1.

Table 88. Quantum Yields of the Acetophenone Formation in Bz-7-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

Run AAP/AMeBe [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10'5 M (Valerophenone) 10.5 M
1 0 574 9 26 0.945 15 25 0 18
2 0597 913 1.072 16 40 016

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.17 I

 

 

Run 1: [Ketone] = 1.0209x10'3 M. [MeBe] = 1.1208x10'3 M. [Valerophenone]
1.0553x10'3 M. Irradiation for 6 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0209x10’3 M. [MeBe] = 1.062lx10'3 M. [Valerophenone]
1.0171x10'3 M. Irradiation for 6 h. HPLC condition set 1.

200

Table 89. Quantum Yields of the Acetophenone Formation in Bz-9-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAF/AMeBe [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10.. M (Valerophenone) 10'5 M
1 0 158* 2 41 0.359 5 48 0 13
2 0 154* 2 35 0.359 5 48 0 13

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.13 1

 

Run 1: [Ketone] = 0.9987x10’3 M. [MeBe] = 1.0606x10'3 M. [Valerophenone]
1.0171x10'3 M. Irradiation for 3 h. HPLC condition set 1.

 

Run 2: [Ketone] = 1.0236x10’3 M. [MeBe] = 1.0606x10‘3 M. [Valerophenone]
1.0171x10'3 M. Irradiation for 3 h. HPLC condition set 1.
*Average of 2 tubes

Table 90. Quantum Yields of the Acetophenone Formation in Bz-10-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAI’IAMeBe [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0 247 3 99 0 945 15 25 0.08 L
2 0 230 3 52 1.072 16 40 0.06

 

 

 

 

 

 

 

 

 

 

L Average Quantum Yield = 0.07

 

Run 1: [Ketone] = 1.0139x10'3 M. [MeBe] = 1.1208x10'3 M. [Valerophenone]
1.0553x10'3 M. Irradiation for 6 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0139x10'3 M. [MeBe] = 1.0621x10'3 M. [Valerophenone]
1.0171x10'3 M. Irradiation for 6 h. HPLC condition set 1.

 

201

Table 91. Quantum Yields of the Acetophenone Formation in Bz-ll-O4Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 1.0040x10'3 M. [MeBe] = 1.1208rt10'3 M. [Valerophenone]

 

Run AAP/AMeBe [AP]. AAn/AMeBe [AP]. ‘1’
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0.756 12.20 0.945 15.25 0.24
2 0.447 6.43 0.751 10.80 0.18
Average Quantum Yield = 0.21 I

 

1.0553x10’3 M. Irradiation for 6 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0274x10'3 M. [MeBe] = 09989x10'3 M. [Valerophenone]

1.0023x10'3 M. Irradiation for 4 h. HPLC condition set 1.

Table 92. Quantum Yields of the Acetophenone Formation in Bz-14-O4Bp with
Valerophenone as an Actinometer at 366 nm in Benzene.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 1.0249x10'3 M. [MeBe] = 1.0018x10'3 M. [Valerophenone]

 

Run AAP/AMeBe [AP], AAP/AMeBe [AP], (I)
(Ketone) 10.5 M (Valerophenone) 10'5 M

1 0.558 8.05 0.674 9.72 0.24

2 0.550 7.93 0.674 9.72 0.24

I Average Quantum Yield = 0.24

 

1.0281x10‘3 M. Irradiation for 6 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0003rt10'3 M. [MeBe] = 1.0018x10'3 M. [Valerophenone]

1.0281x10’3 M. Irradiation for 6 h. HPLC condition set 1.

l :—

 

 

 

202

Table 93. Quantum Yields of the Acetophenone Formation in Bz-3-O2Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBe [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10.5 M (Valerophenone) 10'5 M
1 1 014 18 44 2.094 38 07 0 24
2 0572 1007 1.318 23 21 022

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.23

 

Run 1: [Ketone] = 1.0170x10'3 M. [MeBe] = 1.2627x10'3 M. [Valerophenone] =
0.9819x10'3 M. Irradiation for 14 h. HPLC condition set 1.

Run 2: [Ketone] = 0.9987x10‘3 M. [MeBe] = 1.2228x10'3 M. [Valerophenone]
0.9888x10‘3 M. Irradiation for 10 h. HPLC condition set 1.
[AP] from valerophenone is a sum over consecutive measurements.

Table 94. Quantum Yields of the Acetophenone Formation in Bz-4-02Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBc [AP]. AAP/AMeBe [AP]. ‘1’
(Ketone) 10.5 M (Valerophenone) 10'5 M
1 0 103 1 31 0.650 8 25 0 05
_______________________________________________ L__._-_
2 0 128 1 62 0.820 10 41 0 05

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.05 I

 

Run 1: [Ketone] = 1.0411x10'3 M. [MeBe] = 0.8814x10'3 M. [Valerophenone]
1.0048rt10'3 M. Irradiation for 5 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0412x10'3 M. [MeBe] = 0.8814x10'3 M. [Valerophenone]
1.0048x10'3 M. Irradiation for 6 h. HPLC condition set 1.

21.—«7'

 

1. tiling.-

 

203

Table 95. Quantum Yields of the Acetophenone Formation in Bz-5-02Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

Run AAP/AMeBe [AP ]. AAP/AMenc [AP]. ‘1’
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0 390 5 68 ' 0.661 9 62 0 18
2 0 342 5 02 0.633 9 29 0 l6

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.17 I

 

Run 1: [Ketone] = 1.0043x10'3 M. [MeBe] = 1.0107x10'3 M. [Valerophenone]
0.9887x10'3 M. Irradiation for 5 h. HPLC condition set 1.

II
I

Run 2: [Ketone] = 1.0099x10'3 M. [MeBe] = 1.0195x10'3 M. [Valerophenone]
1.0109x10'3 M. Irradiation for 5 h. HPLC condition set 1.

Table 96. Quantum Yields of the Acetophenone Formation in Bz-6-02Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run Any/Arms: [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10" M (Valerophenone) 10'5 M
1 0 272 3 92 0.624 9 00 0 13
2 0 308 4 42 0.679 9 74 0 14

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.13

 

 

Run 1: [Ketone] = 1.0099rt10'3 M. [MeBe] = 1.0018x10'3 M. [Valerophenone] =
1.0183x10'3 M. Irradiation for 6 h. HPLC condition set 8.

Run 2: [Ketone] = 0.9987.t10'3 M. [MeBe] = 09960x10'3 M. [Valerophenone]
1.0035x10'3 M. Irradiation for 7 h. HPLC condition set 8.

 

204

Table 97. Quantum Yields of the Acetophenone Formation in Bz-7-02Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 0.9933x10’3 M. [MeBe] = 1.0107x10'3 M. [Valerophenone]

 

Run AAP/AMeBe [AP]. AAP/AMene [AP]. 4’
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0.510 7.42 1.153 16.78 0.13
l- — — — . ————————————————————— r— ———————————————————— l— — - - — A
2 0.284 3.83 0.647 8.72 0.13
Average Quantum Yield = 0.13

 

1.0183x10’3 M. Irradiation for 6 h. HPLC condition set 1.

Run 2: [Ketone] = 0.9826x10'3 M. [MeBe] = 0.9364x10'3 M. [Valerophenone]

1.0060x10'3 M. Irradiation for 4 h. HPLC condition set 1.

Table 98. Quantum Yields of the Acetophenone Formation in Bz-9-O2Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 1.0136x10'3 M. [MeBe] = 0.8814x10'3 M. [Valerophenone]

 

Run AAr/AMeac [AP]. AAPIAMeBe [AP]. ‘1’
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0.361 4.58 0.820 10.41 0.13
2 0.397 5.24 0.914 12.06 0.13
Average Quantum Yield = 0.13 I

 

1.0048x10'3 M. Irradiation for 6 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0037x10'3 M. [MeBe] = 0.9166x10'3 M. [Valerophenone]

1.0047x10'3 M. Irradiation for 6 h. HPLC condition set 1.

 

205

Table 99. Quantum Yields of the Acetophenone Formation in Bz-lO-O2Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 1.0131x10’3 M. [MeBe] = 0.9490x10'3 M. [Valerophenone]

 

Run AAP/AMeBe [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10'5 M (Valerophenone) 10" M
1 0.345 4.71 0.763 10.43 0.13
2 0.344 4.99 0.814 11.81 0.12
Average Quantum Yield = 0.13

 

0.9961x10’3 M. Irradiation for 7 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0035x10'3 M. [MeBe] = 1.0077x10'3 M. [Valerophenone]

1.0109x10‘3 M. Irradiation for 7 h. HPLC condition set 1.

Table 100. Quantum Yields of the Acetophenone Formation in Bz-11-02Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

Run 1: [Ketone] = 1.0220x10'3 M. [MeBe] = 0.9490x10’3 M. [Valerophenone]

 

Run AAP/AMcBe [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10" M (Valertmhenone) 10'5 M
1 0.471 6.44 0.763 10.43 0.18
2 0.536 7.78 0.814 11.81 0.19
Average Quantum Yield = 0.19

 

0.9961x10'3 M. Irradiation for 7 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0080x10'3 M. [MeBe] = 1.0077x10'3 M. [Valerophenone]

1.0109x10'3 M. Irradiation for 7 h. HPLC condition set 1.

 

 

206

Table 101. Quantum Yields of the Acetophenone Formation in Bz-14-02Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

Run AAP/AMeBe [AP], AAP/AMeBe [AP 19 (D
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0 422 6 12 0.647 9 39 0 19
2 0 484 6 98 0.675 9 74 0 21

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.20

 

Run 1: [Ketone] = 0.9999x10’3 M. [MeBe] = 1.0077x10‘3 M. [Valerophenone]
1.0109x10'3 M. Irradiation for 6 h. HPLC condition set 8.

Run 2: [Ketone] = 1.0113x10'3 M. [MeBe] = 1.0018x10‘3 M. [Valerophenone]
0.9996x10'3 M. Irradiation for 6h. HPLC condition set 8.

Table 102. Quantum Yields of the Acetophenone Formation in Bz-3-O3Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBe [AP]. AAIJAMeBe [AP]. 9’
(Ketone) 10'5 M (Valerophenone) 10.5 M
1 0 802 14 58 2.094 38 07 0 20
2 0498 877 1.318 23 21 019

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.20

 

Run 1: [Ketone] = 1.0138x10'3 M. [MeBe] = 1.2627x10'3 M. [Valerophenone]
0.9819x10'3 M. Irradiation for 14 h. HPLC condition set 1.

Run 2: [Ketone] = 0.9987x10'3 M. [MeBe] = 1.2228x10'3 M. [Valerophenone]
0.9888x10'3 M. Irradiation for 10 h. HPLC condition set 1.
[AP] from valerophenone is a sum over consecutive measurements.

 

207

Table 103. Quantum Yields of the Acetophenone Formation in Bz-6-O3Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBe [AP]. AAP/AMeBc . [AP]. 4’
(Ketone) 10.5 M (Valerophenone) 10'5 M
1 0 337 4 86 0.624 9 00 0 16
2 0411 589 0.679 974 018

 

 

 

 

 

 

 

 

 

I Average Quantum Yield = 0.17

 

Run 1: [Ketone] = 0.9987x10'3 M. [MeBe] = 1.0018x10'3 M. [Valerophenone] =
1.0183x10'3 M. Irradiation for 6 h. HPLC condition set 8.

Run 2: [Ketone] = 0.9931x10'3 M. [MeBe] = 0.9960x10'3 M. [Valerophenone] =
1.0035x10'3 M. Irradiation for 7 h. HPLC condition set 8.

Table 104. Quantum Yields of the Acetophenone Formation in Bz-7-O3Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

Run AAP/AMeBe [AP 19 AAP/AMeBe [AP], (1)
(Ketone) 10’5 M (Valerophenone) 10'5 M
1 0642 934 1.153 1678 017
2 0 406 5 47 0.647 8 72 0 19

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.18

 

Run 1: [Ketone] = 0.9933x10'3 M. [MeBe] = 1.0107x10'3 M. [Valerophenone] =
1.0183x10’3 M. Irradiation for 6 h. HPLC condition set 1.

Run 2: [Ketone] = 1.0041x10’3 M. [Mch] = 0.9364x10'3 M. [Valerophenone]
1.0060x10'3 M. Irradiation for 4 h. HPLC condition set 1.

Table 105. Quantum Yields of the Acetophenone Formation in Bz-9-O3Bp

208

Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

 

Run AAP/AMeBe [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0.270 3.87 0.526 7.54 0.15
Average Quantum Yield 0.15

 

with

Run 1: [Ketone] = 1.0087x10'3 M. [MeBe] = 0.9960x10'3 M. [Valerophenone] =
1.0035x10'3 M. Irradiation for 6 h. HPLC condition set 10. Single measurement.

Table 106. Quantum Yields of the Acetophenone Formation in Bz-10-03Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

 

 

 

 

 

 

 

 

Run AAP/AMeBe [AP]. AAP/AMeBe [AP]. 4’
(Ketone) 10.5 M (Valerophenone) 10'5 M

1 0.336 4.82 0.526 7 .54 0.19

2 0.313 4.49 0.536 7.69 0.17

I Average Quantum Yield 0.18

Run 1: [Ketone] = 0.9987x10'3 M. [MeBe] = 0.9960x10'3 M. [Valerophenone]

 

1.0035x10'3 M. Irradiation for 6 h. HPLC condition set 10

Run 2: [Ketone] = 1.0035x10'3 M. [MeBe] = 0.9960x10'3 M. [Valerophenone]

1.0035x10'3 M. Irradiation for 6 h. HPLC condition set 10.

209

Table 107. Quantum Yields of the Acetophenone Formation in Bz-l4—O3Bp with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAP/AMeBe [AP]. AAP/AMeBe [AP]. ‘1’
(Ketone) 10'5 M (Valerophenone) 10'5 M
l 0 303 4 35 0.536 7 69 0 l7
2 0310 442 0.502 748 018

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.17 I

 

Run 1: [Ketone] = 0.9985x10‘3 M. [MeBe] = 0.9960x10'3 M. [Valerophenone]
1.0035x10‘3 M. Irradiation for 6 h. HPLC condition set 10.

Run 2: [Ketone] = 1.0028x10'3 M. [MeBe] = 1.0342x10'3 M. [Valerophenone]
0.9986x10'3 M. Irradiation for 6 h. HPLC condition set 8.

Table 108. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-3-0Np
with Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AMeAP/AMeBe [MeAP], AAPIAMeBe [AP], (I)
(Ketone) 10.5 M (Valerophenone) 10'5 M
1 0 040 1 70 0.224 27 63 0 03
2 0041 195 0.212 29 26 004

 

 

 

 

 

 

 

 

 

r Average Quantum Yield = 0.03

 

Run 1: [Ketone] = 0.9837x10'3 M. [MeBe] = 0.9636x10’3 M. [Valerophenone] =
1.0232rt10'3 M. Irradiation for 48 h. HPLC condition set 3.

Run 2: [Ketone] = 0.9961x10‘3 M. [MeBe] = 1.0782x10’3 M. [Valerophenone]
1.0193x10'3 M. Irradiation for 48 h. HPLC condition set 3.
[AP] from valerophenone is a sum over consecutive measurements.

210

Table 109. Quantum Yields of the 4-Methy1acetophenone Formation in MeBz-4-0Np
with Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AMeAPIAMeBe [MEAP]. AAP/AMeBe [AP]. (P
(Ketone) 10'5 M (Valerophenone) 10.5 M
1 0107 492 1.164 14899 001
2 0 060 2 76 0.522 69 78 0 01

 

 

 

 

 

 

 

 

 

I Average Quantum Yield = 0.01

 

Run 1: [Ketone] = 0.9893x10'3 M. [MeBe] = 1.0459x10'3 M. [Valerophenone] =
1.0158rt10'3 M. Irradiation for 41 h. HPLC condition set 3.

Run 2: [Ketone] = 1.0058x10'3 M. [MeBe] = 1.0444rt10'3 M. [4-methylvalerophenone] =
1.0065x10'3 M. Irradiation for 24 h. HPLC condition set 3.

[AP] from valerophenone is a sum over consecutive measurements.

Table 110. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-S-ONp
with Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

Run AMeAP/AMeBe [MCAP], AAP/AMeBe [AP], (D
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0.328 15.09 1.164 148.99 0.03
2 0 197 9 05 0.522 69 78 0 04

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.03

 

Run 1: [Ketone] = 0.9777x10’3 M. [MeBe] = 1.0459x10'3 M. [Valerophenone] =
1.0158x10'3 M. Irradiation for 41 h. HPLC condition set 3.

Run 2: [Ketone] = 1.0236x10'3 M. [MeBe] = 1.0444x10'3 M. [4-methylvalerophenone] =
1.0065x10‘3 M. Irradiation for 24 h. HPLC condition set 3.

[AP] from valerophenone is a sum over consecutive measurements.

211

Table 111. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-6-0Np
with Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AMeAP/AMt-Be [MeAP]. AAP/AMeBe [AP]. <I>
(Ketone) 10-5 M (Valerophenone) 10'5 M
1 0400 1841 1.164 14899 004
2 0 238 10 94 0.522 69 78 0 05

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.04 I

 

Run 1: [Ketone] = 101037110"3 M. [MeBe] = 1.0459x10'3 M. [Valerophenone] =
1.0158x10’3 M. Irradiation for 41 h. HPLC condition set 3.

Run 2: [Ketone] = 1.0110x10'3 M. [MeBe] = 1.0444x10'3 M. [4-methylvalerophenone] =
1.0065x10'3 M. Irradiation for 24 h. HPLC condition set 3.

[AP] from valerophenone is a sum over consecutive measurements.

Table 112. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-7-0Np
with Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

Run AMeAP/AMeBe [MeAP], AAPIAMeBe [AP]. ‘1’
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 O 530 24 39 1.164 148 99 0 05
2 0 276 12 68 0.522 69 78 0 05

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.05

 

Run 1: [Ketone] = 1.0126x10‘3 M. [MeBe] = 1.0459x10'3 M. [Valerophenone] =
1.0158x10'3 M. Irradiation for 41 h. HPLC condition set 3.

Run 2: [Ketone] = 1.0272x10'3 M. [MeBe] = 1.0444x10'3 M. [4-methylvalerophenone] =
1.0065x10'3 M. Irradiation for 24 h. HPLC condition set 3.

[AP] from valerophenone is a sum over consecutive measurements.

.~rv ‘. Banning

 

 

 

212

Table 113. Quantum Yields of the 4-Methylacetophenone Formation in
MeBz-l l-ONp with Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

Run AMeAP/AMeBe [MEAP]. AAP/AMeBc [AP]. 4’
(Ketone) 10'5 M (Valerophenone) 10'5 M
l 0575 26 46 1.164 14899 005
2 0 302 13 88 0.522 69 78 0 06

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.06

 

Run 1: [Ketone] = 1.0082x10'3 M. [MeBe] = 1.0459x10’3 M. [Valerophenone] =
1.0158x10’3 M. Irradiation for 41 h. HPLC condition set 3.

Run 2: [Ketone] = 0.9849x10'3 M. [MeBe] = 1.0444x10'3 M. [4-methylvalerophenone] =
1.0065x10'3 M. Irradiation for 24 h. HPLC condition set 3.

[AP] from valerophenone is a sum over consecutive measurements.

Table 114. Quantum Yields of the 4-Methylacetophenone Formation in MeBz-3-O4Bp
with Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

 

Run AMeAP/AMeBe [MBAP], AAF’AMeBe [AP], (D
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0 049 2 08 0.224 27 63 0 04
2 0 244 0 76 0.947 11 86 0 03

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.04

 

Run 1: [Ketone] = 0.9844x10'3 M. [MeBe] = 0.9636x10'3 M. [Valerophenone] -
1.0232x10'3 M. Irradiation for 48 h. HPLC condition set 3.
[AP] from valerophenone is a sum over consecutive measurements.

Run 2: [Ketone] = 0.9876x10'3 M. [MeBe] = 0.8696x10’3 M. [Valerophenone]
1.0224x10'3 M. Irradiation for 45 h. HPLC condition set 1.

213

Table 115. Quantum Yields of the Acetophenone Formation in Bz-3-O-2-O43p with
Valerophenone as an Actinometer at 366 nm in Cyclohexane.

 

 

Run AAI’IAMeBe [AP], AAP/AMeBe ' [AP], (1)
(Ketone) 10'5 M (Valerophenone) 10'5 M
1 0 307 4 47 0.661 9 62 O 18
2 0 284 4 17 0.633 9 29 0 17

 

 

 

 

 

 

 

 

 

 

Average Quantum Yield = 0.17 I

 

' .00!“

Run I : [Ketone] = 0.9988x10’3 M. [MeBe] = 1.0107x10'3 M. [Valerophenone]
0.9887x10'3 M. Irradiation for 5 h. HPLC condition set 1.
Run 2: [Ketone] = 1.0155x10'3 M. [MeBe] = 1.0195x10’3 M. [Valerophenone]
1.0109x10'3 M. Irradiation for 5 h. HPLC condition set 1.

u-

 

 

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A; ..~-r'" -.—-.-' ——
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