9’3 <. is};
{‘34ng 303’}?
3.31 4‘s-

e
|

.'J )

._ 4

V "’;‘-"\:\‘\( J
‘ syi‘w ‘.~

9’ ”£72553”;

3., . . .

I 5: I" " . CH V'

. . , ‘ 3. sua ; ~v «44ml.

. "If-w. - ‘ 453.. 4. ~ ‘ 3‘ ‘3 ‘1’ "' a?“ ‘3 «131-3135;;-

u, g s “ r. ”3.341;,“ 5b -\ I? ' ‘7 X. g—NPL

4' -‘:,‘ut,..,mrf 341’, a “’1’ a. "‘- J‘ »-

, ».;;t:;cs>v “5‘35! 3;; ,

3-3.4

sJ ' e V 3
a; :1 , 8' .,:.:s..: 3“ ' m ”.4 a 9. ‘
«.. - .3, ,.,.I s , - ‘ .., I» r ,
‘ ' . 1.x? . s x 4, 1‘ , y' Q .3“, _,
.' ‘ ”A. 9‘1. ‘4 ‘ #293,. - 3,313.3.” Pi? 3" ‘3ng NH. .4 ;, IQ 3,32, 3 ‘I ’3' .V '33? ,4.
3"er 3 ‘5 -"‘YJ""I“"" ‘ - ' -‘ 1.4 '. 3 w,- ‘W': s - 5H“ ’r'M ’
’ " s' ‘- ‘ ‘ ‘ '» ~ « ‘ “a" ~ ‘ ‘ 1. ‘5. " ‘L‘Tz'm 11"“ fixinfifffl 7 ‘3}. .‘ 1.-
4!: ‘ “ - ‘ ' a r “ (A v.9". \w 3 f» .u - - 34" "ARA ' -
3 '3' I" ‘ ‘ 'fi ‘ "f“ H ”“0": ' s F "k "N" x " "N :flxhr‘:
$3434 -' - vi ,, ‘ 4211‘»: "\‘f. “‘ '3 .,3 Ni x 3 ~ A -. 4 f ‘2: 3 W a a? 375354-533
"‘3” E h‘ ~u ‘ I ‘ ‘- J - “> - "3 $ucfi‘5;lfi r . ‘ s .7 :flv‘: ‘1' .J‘l‘ss‘fi \‘ 3 '- afig‘t‘gfik $9“! I}!
. VA ' 21L" :5 1V 1‘ , n . i . 7 an ‘ ' ‘ S 1
.‘3 4
1%!”

F" 7.1 A y

N
. s A. 3 ‘n- . 0
“@§\ ‘ gfla,‘;_.flf‘3‘
"933$" . - q a ." ”2" 4m, n
“3 ‘33s '3- - 'va I; {33% 3.33
h - “(ktm‘wifinfl a
w v. -
’K

4") I , f". _ A:
‘ ‘ I ' , ‘( Jfi; 1 > f :34' " ,w

5’
c t...
s. {322.341 .. . ., ,3
““C‘Ikhfi’ ‘ - . , ’ - . ' ' "7 3» 5,633) 3 in s . s } z M2741.
«9'4 " j . ' - “N 3%; 56.3... ' . x§qk>§mwg ‘
... 2.4 . _ 3 ‘ “#21; . \ 4 j .‘m .4 _‘ - ‘1‘. .4 kfllzywbw
(:32 4:4 ,3 he w "mo-33: 439;
U

”i?!-

3.33

(I.

:2?” 4"" ‘
. $643423;
Ms‘ytww

 

vac; A .x .7; ~
.

l 7 ~_ g‘l
(qua-

#5: ‘ .‘n -
.hJufia‘h" «4.,-
~.a -ven vs 3“

“ Tn»
..

lc~'r',r_':

rd". :4.“ -.'V,‘(.~: .! n. r r-rm ( ».)£ k‘v-q-wu viva «1:413 ‘n; ;
‘4 « UM: A ‘ " ' .
_" flail-41:2.» .-

‘

- iifihn'lfighhk’}

émnfinrmum m
fiW‘J‘vJ.‘

,M

raft"; .

s 2-27-03 h,

~ 3.. W: fiwvfs'w ' xvmééxfisar ' '

w M .a . '- ‘ m; "T .-.Wr"f"""’
"re-rd v ‘ V .-

m:’-">rT/?‘r.~ Ms. ware-w.” «33.;
$74 at? fit-'Wi-‘émrrr; ’3 12%,. 4 v4 '1

I'll“: 1,. r'4'“'z.l.',~-3'r W‘wwnqw-g: "' 3

'w- .. ', r: n - ”MW-Ann;

‘ £3415

o
.-

3,’ , "swv
-.. «w .. ..
93“.“; ,3, .3. " .. :fl, 3 v '4”
far" ;' m- “’3‘.”
- - "£31"
(”33(5" ("3 s.
3;.» - >0:"";,’,€‘ 2 ,

..-..,.=.---.. 3 ‘ \ g

"was”? “'5'.“ urn

7"‘f'm . » ..., ‘ ... :1.

. vv- ‘ s. 3 . . us- ,
v J‘ ,J.‘ 37-1 ”0M:E_om 139.130.“ Y2.‘:&.;. z

man-w 8"""‘?“w I“:
,... a.» r . . If!
a thy- , .3354 ‘1. ~

{in an: . "
“.3 s r .
"‘ 3-4 "'5‘ "2:22.

nun-
:-

 

l/II

 

III

II3II3I3IIII3III 33 33 333333

 

 

 

This is to certify that the

thesis entitled

THE PHOTOCHEMISTRY OF META AND PARA
IODOB ENZ OPHEN ONES

presented by

Carol Ismay Waite

has been accepted towards fulfillment
of the requirements for

Ma. stgrs degree in Chemistry

.x/flgiffl»

flMajor thofessor

 

flzc, N9; /?(%9

0-7 639 MS U is an Affirmative Action/Equal Opportunity Institution

 

LIBRARY W
Michigan State

University 3
L\ I

 

 

23330 34907

 

 

PLACE IN RETURN BOX to remove this checkout from your record.
TO AVOID FINES return on or bdom date due.

 

DATE DUE DATE DUE DATE DUE

—- I
__l
—— ll

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MSU Io An Minn-mo Action/Equal Opportunity Institution
chS-nt

 

THE PHOTOCHEMISTRY OF META AND PARA-IODOBENZOPHENONES

BY

Carol Ismay Waite

A THESIS

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

MASTER OF SCIENCE
Department of Chemistry

1987

LMJLLQ‘

ABSTRACT

THE PHOTOCHEMISTRY OF META AND
PARA IODOBENZOPHENONES

BY
Carol Ismay Waite

The photochemistry of iodo substituted benzophenones has
been studied in order to determine the rate constants of
cleavage of the carbon-iodine bond. Rate constants were
calculated from triplet lifetimes obtained from quenching
experiments.

The quenching experiments were performed on both m- and p-
iodobenzophenones in various solvents. The solvents employed
were cyclopentane, cyclooctane, methanol-ethanol and t-
butylalcohol solvent mixtures, acetonitrile containing n-
octanethiol, and carbon tetrachloride. Naphthalene was used as
quencher in all solvents.

The triplet lifetimes of the para isomer were found to be
viscosity dependent while those for meta were influenced by
solvent polarity. Product quantum yields for both isomers were
dependent on solvent viscosity.

Photolysis of both m- and p-iodobenzophenones gave
radicals that result from the loss of iodine from the aromatic
ring. These radicals underwent hydrogen abstraction from a
hydrogen donor molecule to give benzophenone or chlorine atom
abstraction from carbon tetrachloride solvent to give the

corresponding chlorobenzophenones.

To my family

Keith and Gloria Waite
Carla, Cynthia and Keith, Jr.

iii

Acknowledgements

I thank Dr. Peter J. Wagner for his priceless
advice of never giving up; Dr. Chang, Dr.
LeRoi and Dr. Nocera for serving on my
guidance committee; the Wagner group for
their ceaseless encouragement; N.J. Sabater,
C.M. Cullen and J.D. Thomas for being such
great friends as they are; and the National
Science Foundation and Michigan State
University for their financial support.

/

iv

LIST OF TABLES . . .
LIST OF FIGURES . .
INTRODUCTION . . . .
RESULTS . . . . . .
DISCUSSION . . . . .

Solvent Effects

Carbon-Halogen Bond

EXPERIMENTAL . . . .

TABLE

OF CONTENTS

Preparation and Purification of

Solvents .

Acetonitrile

Benzene .

t-Butanol

Carbon tetrachloride

Cyclooctane .

Cyclopentane

Ethanol

Hexane

Methanol

Internal Standards

Ethylbenzoate .

Methylbenzoate

n-Pentylbenzoate

Chemicals

xii

xix

11
28
28
34
37
37
37
37
37
38
38
38
38
39
39
39
39
39
40

40

n-Nonylbenzoate . . . . . . . .

Hydrogen Donor . . . . . . . . . . .
n-Octanethiol . . . . . . . . .

Quencher . . . . . . . . . . . . . .
Naphthalene . . . . . . . . . .

Chemicals used in the identification
photoproducts . . . . . . . . .
Benzophenone . . . . . . . . .

m- and p-Chlorobenzophenone . .

Ethylene glycol . . . . . . . .
Hexachloroethane . . . . .‘. .

Iodine . . . . . . . . . . . .

Synthesis . . . . . . . . . . . . .
m-iodobenzophenone . . . . . .
p-iodobenzophenone . . . . . .
Preparation and Irradiation of Samples .
Non-polar solvents . . . . . . . . .
Polar Solvents . . . . . . . . . . .
Benzophenone and iodobenzophenone in
Quantitative Analysis . . . . . . . . . .
Calculation of Quantum Yields . . . . . .
Identification of Photoproducts . . . . .

Instrumentation . . . . . . . . . . . . .

TABLES O O O O O C O O O O O O O O O O O O O 0

LIST OF “FERENCES O O O O O O O O O O O O O O

cyclopentane

40
4O
40
4O

4O

40
40
4O
4O
40
41
41
41
54
58
63
64
65
73
75
80
90
96

117

I.

II.

III.

IV.

V.

VI.

VII.

LIST OF TABLES

Quantum yields of benzophenone formation at 3130A in
various solvents . . . . . . . . . . . . . . . . . .
Viscosity of the various solvents . . . . . . . . . .
A summary of qu values, kq values and lifetimes of
triplet excited states . . . . . . .1. . . . . . . .
Rate constants for carbon-iodine bond cleavage .'. .
Ring fundamentals (cm'l) of m-bromo and m-
iodobenzophenones in the range 1700-80 cm.‘1 . . . .
C-C(O)C Group fundamentals (cm‘l) of m-hromo and m-
iodobenzophenones in the range of 1700-80 cm"1 . . .
A summary of 1H NMR spectra of some simple

monosubstituted halobenzenes . . . . . . . . . . . .

VIII.Ultraviolet and phosphorescence spectra of

IX.

X.

XI.

iodobenzophenones . . . . . . . . . . . . . . . . . .
Ring fundamentals (cm‘l) of p-bromo and p-
iodobenzophenones in the range 1700-80 cm."1 . . . .
CC(0)C Group fundamentals (cm'l) of p-bromo and p-

iodobenzophenones in the range of 1700-80 cm’1 . . .

Response factors for quantitative analysis on both g.c.

and ICC. O O O O O O O O I O O O O O O O O O O O O O

XII. Photochemical data from valerophenone (0.10M)

actinometers . . . . . . . . . . . . . . . . . . . .

XIII.Extinction coefficients . . . . . . . . . . . . . . .

1.

Quenching of 0.0186 M m-iodobenzophenone in cyclopentane

vii

13

29

30

32

43

44

48

49

55

56

74

77

95

10.

11.

12.

13.

14.

at 3650 A . . . . . . . . . . . . . . . . . . . . . . . 96
Quenching of 0.0191 M m-iodobenzophenone in cyclooctane

at 3650 A . . . . . . . . . . . . . . . . . . . . . . . 97
Quenching of 0.0149 M p-iodobenzophenone in cyclopentane

at 3650 A . . . . . . . . . . . . . . . . . . . . . . . 98
Quenching of 0.0150 M p-iodobenzophenone in cyclopentane

at 3650 A . . . . . . . . . . . . . . . . . . . . . . . 99
Quenching of 0.0149 M p-iodobenzophenone in cyclooctane

at 3650 A . . . . . . . . . . . . . . . . . . . . . . . 100
Quenching of 0.0152 M p-iodobenzophenone in cyclooctane

at 3650 A . . . . . . . . . . . . : . . . . . . . . . . 101
Quenching of 0.00593 M m-iodobenzophenone in 9:1
methanol-ethanol at 3650 A . . . . . . . . . . . . . . 102
Quenching of 0.00552 M m-iodobenzophenone in 9:1
methanol-ethanol at 3650 A . . . . . . . . . . . . . . 103
Quenching of 0.00608 M m-iodobenzophenone in 9:1
methanol-ethanol at 3650 A . . . . . . . . . . . . . . 104
Quenching of 0.00579 M m-iodobenzophenone in 8:2 t-
butanol-ethanol . . . . . . . . . . . . . . . . . . . . 105
Quenching of 0.00484 M p-iodobenzophenone in 9:1
methanol-ethanol at 3650 A . . . . . . . . . . . . . . 106
Quenching of 0.00481 M p-iodobenzophenone in 8:2 t-
butanol-ethanol at 3650 A . . . . . . . . . . . . . . . 107
The effect of added thiol on the photochemistry of 0.0185

M m-iodobenzophenone in acetonitrile at 3130 A . . . . 108

Quenching of 0.0188 M m-iodobenzophenone in the presence

\dii

15.

16.

17.

18.

19.

20.

of added thiol in acetonitrile at 3650 A . . . . . . . 109
The effect of added thiol on the photochemistry of 0.0186

M p-iodobenzophenone in acetonitrile at 3650 A . . . . 110
Quenching of 0.0185 M p-iodobenzophenone in the presence

of added thiol in acetonitrile at 3650 A . . . . . . . 111
Quenching of 0.0186 M m-iodobenzophenone in carbon
tetrachloride at 3650 A . . . . . . . . . . . . . . . . 112
Quenching of 0.0190 M m-iodobenzophenone in carbon
tetrachloride at 3650 A . . . . . . . . . . . . . . . . 113
Quenching of 0.0149 M p-iodobenzophenone in carbon
tetrachloride at 3650 A . . . . . 3 . . . . . . . . . . 114
Quenching of 0.0154 M p-iodobenzophenone in carbon

tetraChloride at 3 650 A O O O O O O O O O O O O O O O O 115

10.

11.

LIST OF FIGURES
Stern-Volmer plot of m-iodobenzophenone in cyclopentane
Stern-Volmer plots of p—iodo-benzophenone in cyclopentane
Stern-Volmer plots of p-iodobenzophenone in cyclopentane
(D) and in cyclooctane (.) . . -,.- . . . . . . . .3
Stern-Volmer plots of p-iodobenzophenone in cyclopentane
(.) and in cyclooctane (D) . . . . . . . . . . . .
Stern-Volmer plot of m-iodobenzophenone in 9:1 methanol-
ethanol . . . . . . . . . . . . . . ... . . . . ... . .
Stern-Volmer plots of p-iodobenzophenone in 9:1 methanol-
ethanol (.) and in 8:2 t-butanol-ethanol (O) . . .
The effect of added thiol on the quantum yield of
formation of benzophenone from m-iodobenzophenone in
acetonitrile . . . . . . . . . . . . . . . . . . . . .
The effect of added thiol on the quantum yield of
formation of benzophenone from p-iodobenzophenone in
acetonitrile . . . . . . . . . . . . . . . . . . . . .
Stern-Volmer plot of m-iodobenzophenone in carbon
tetrachloride . . . . . . . . . . . . . . . . . . . . .
Stern-Volmer plot of p-iodobenzophenone in carbon
tetrachloride . . . . . . . . . . . . . . . . . . . . .
Quantum yields of benzophenone formation from m-
iodobenzophenone (Q ) and p-iodobenzophenone ( . )

as a function of solvent viscosity . . . . . . . . . .

14

15

16

17

19

21

22

24

25

33

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

IR spectrum of m-iodobenzophenone in C52 . . . . . . .
IR spectrum of benzophenone in C82 . . . . . . . . . .
la NMR spectrum of m-iodobenzophenone in CDCL3 relative
to TMS . . . . . . . . . . . . . . . . . . . . . . . .
13 NMR of benzophenone in CDCL3 relative to TMS . . . .
UV spectrum of m-iodobenzophenone in cyclopentane . . .
Phosphorescence spectrum of m-iodobenzophenone . . . .
IR spectrum of p—iodobenzophenone in C82 . . . . . . .
1H NMR spectrum of p-iodobenzophenone in CDC13 relative

to ms O O O O O O O O O O O O O O .O O O O O O O O O O

1HNMR spectrum of p-chlorobenzophenone in CDC13 relative

to TMS . . . . . . . . . . . . . . . . . . . . . . . .
UV spectrum of p-iodobenzophenone in cyclopentane . . .
Phosphorescence spectrum of p-iodobenzophenone . . . .
The g.c. trace of the irradiated sample of benzophenone

and iodobenzene in cyclopentane . . . . . . . . . . . .

Mass spectrum of iodobenzene in the irradiated sample of

benzophenone and iodobenzene in cyclopentane . . . . .
Mass spectrum of n-pentylbenzoate in the irradiated
sample of benzophenone and iodobenzene in cyclopentane
Mass spectrum of benzophenone in the irradiation of
benzophenone and iodobenzene in cyclopentane . . . . .
Mass spectrum of benzpinacol in the irradiation of
benzophenone and iodobenzene in cyclopentane . . . . .
The g.c. trace of an irradiated sample of

iodocyclopentane resulting from the irradiation of p-

xi

45

46
50
51
52
53
57
59
6O
61
62
67
68
69

70

71

29.

30.

31.

32.

33.

34.

35.

36.

37.

iodobenzophenone . .

Mass spectrum of benzophenone resulting from the

irradiation of m-iodobenzophenone .

Mass spectrum of benzophenone resulting from the

irradiation of p-iodobenzophenone .

Mass spectrum of benzophenone obtained from the library

0 f the GCMS O O O O O

Mass spectrum of iodocyclopentane resulting from the

irradiation of paiodobenzophenone .

Mass spectrum of m-chlorobenzophenone resulting from the

irradiation of m-iodobenzophenone .

Mass spectrum of m-chlorobenzophenone from the library of

the GCMS O O O O O O

Mass spectrum of p-chlorobenzophenone from the library of

the GCMS . . . . . .

Mass spectrum of hexachloroethane resulting from the

irradiation of p-iodobenzophenone .

Mass spectrum of hexachloroethane obtained from the

library of the GCMS .

72

81

82

83

84

85

86

87

88

89

INTRODUCTION

INTRODUCTION

The photochemistry of the carbon-halogen bond has been
the subject of numerous investigations.1'35 The initial
reaction of organic halides upon irradiation is the homolytic
cleavage of the carbon-halogen bond.1r2

Recent studies have indicated the occurrence of ionic
reactions upon irradiation of some organic halides. Kropp et
al.3'7110 and Cristol et al.8v9111‘13 have reported that alkyl.
halides, particularly iodides, frequently afforded products
derived from not only radical reactions but also from
carbocationic intermediates. The observed products were the
result of carbocationic intermediates undergoing isomerization,
Wagner-Meerwein rearrangement, nucleophilic trapping by the
solvent and elimination. In all cases reduction products were
detected.

The alkyl halides studied included halosubstituted
norbornanes, adamantanes and n-octanes,3"5 simple cyclic and
acyclic halides,5'7 vinyl halides,6 and halogen derivatives of
dibenzobicyclooctadiene,8 -nonatriene,9 and
benzotricyclooctene8 systems. These compounds were studied in

various liquid media.

(P5:
:Vui

‘v~

O‘.

SE:

c,,
4“

I‘M
rm

‘ ‘7
6‘“

3
In solution the initially generated radical pair is
assumed to undergo electron transfer within the radical cage
giving an ion pair and, ultimately, carbocationic products
(Scheme 1).3r5r1° This mechanism is preferred to that
described by the simultaneous occurrence of two competing

modes of cleavage, homolysis vs. heterolysis.9

menu

hv
RX-—>(R'°X):.:ER° + X°—> radical products

electron transfer

(R"' X') :2- R+ + x" —-> ionic products

Photoproducts resulting from carbocationic intermediates
are not restricted to alkyl and vinyl halides but also occur to
a lesser extent in the photolysis of benzyl chlorides. Direct
irradiation of benzyl chloride with light of wave length 2540A
in methanol and ethanol gave only radical products11 while in
t-butyl alcohol photosolvolysis products accompanied the
expected radical products. Photo-sensitization with acetone at
3000A led to products derived from benzyl cations.

Direct irradiation of benzyl chloride and its derivatives
favored carbon-halogen bond homolysis while triplet
sensitization encouraged heterolysis.11’13 Results obtained
from studies on the substituent effects upon the
photochemistry of various benzyl chlorides suggest the

involvement of two excited triplet states. Both states are

4
assumed accessible via the first singlet state and may
contribute to the influence direct irradiation vs. triplet
sensitization has on the formation of homolysis vs.
heterolysis products.13

Halobenzenes do not give ionic photoproducts. Products
resulting from radical reactions occurred while those derived
from nucleophilic trapping of a carbocationic intermediate by
alcoholic solvents were not observed.

The irradiation of halobenzenes with light of wave length
2540A produced radical species formed from the homolysis of the
carbon-halogen bond, proposed by Lemal and co-workers to be a
high energy isomer of the original halobenzene referred to as_

'7-halobenzene.”14 The resultant aryl radical

X hv
Q 2540A

generally underwent hydrogen atom abstraction resulting in the

 

t-halobenzene

photoreduction of the carbon-halogen bond15 and/or addition to
an aromatic solvent molecule.
Y Y

hv
q s + HX + pinacol
Eton or i-PrOH

X

 

x - Cl, Br or I

Y - a, on, ocx3 or CH3

30

5k
N.

 

(ii:

X - Br or I

Y a H, Oh, OCH3, CH3CO or CH3C02

Considering the absence of any rearrangement of the
initially formed aryl radicallé'18 photolysis of substituted
haloaromatic compounds, especially bromides and iodides are
useful methods for the synthesis of biphenyl,13'24
polyphenyl,18v24125 and phenanthrenenr26 derivatives,
organometallics,27’29 and compounds having benzyne-like
intermediates.24

The occurrence of light-induced phenylation in benzene is
not limited to arylhalides. Kharasch and Gotlich have shown
that the reaction can be applied to other types of organic
halides, particularly iodides.3°

Photo-induced cleavage of the carbon-halogen bond also
occurs in some aromatic ketones substituted in the ring. Baum
and Pitts31 reported that the irradiation of p-bromo-
butyrophenone with 3000A light formed the unsubstituted
butyrophenone as the major photoproduct. No detectable amount
of Type II photoproducts were observed. The meta isomer and
the valerophenone analogue32 underwent photoreduction of the
carbon-halogen bond to a lesser extent while the p-chloro and

p-fluorobutyrophenones gave exclusively Type II photo-

6
products.31r32 Sedon showed that p-chloromethylvalero-
phenones gave only the reduction product, p-methylvalero-
phenone33, while the p-bromo, m-bromo and m-CHZCl compound
gave mixtures of Type II and reduction products.34

Photo-induced homolysis is in competition with Norrish
Type II photocyclization and elimination reactions. The
presence of Y-carbon-hydrogen bond in the alkyl chain of
phenyl alkyl ketones allows for the characteristic 1,5
hydrogen-shift to occur upon irradiation giving a 1,4
biradical intermediate.36 This biradical undergoes'cleavage
in the alkyl chain to form elimination products and
cyclization to form phenyl substituted cyclobutanols.37 The
presence of a halogen or halomethyl substituent allows the
phenyl alkyl ketone to follow two different pathways (Scheme
2).38

There has been little study on the photochemistry of
halobenzophenones even though the unsubstituted benzophenone
has been widely studied.

Benzophenone undergoes photoreduction of the carbonyl
group in various alcoholic solvents via hydrogen atom
abstraction by the carbonyl oxygen giving a hemipinacol radical
(I). The dimerization of this radical yields the benzopinacol
(II) (Scheme 3).39'4° Chloro- and fluoro-benzophenones'
photobehavior is quite similar to that of benzophenone. Both
halobenzophenones undergo photoreduction of the carbonyl group

in cyclopentane giving products derived from their hemipinacol

7

radicals.41 Photoreduction of the carbon-halogen bond is not

 

 

observed.
SEREEMlJZ
R1
0
R2 hv Q isc
A, 1K* A /3K*\
3130A
X or
Cfizx OH
X a C1 or Br
-or OK or
' QChf
Cleavage Type II
radical products products

0*0 awn—01:0 >—w
was. + >0

2 ‘3“ 3.0
O 0 0:0

Unlike chloro- and fluorobenzophenones, the bromo- and

iodo-counterparts do not give benzopinacol formation, instead

8
they gave products resulting from carbon-halogen bond
homolysis. Irradiation of bromo- and iodobenzophenones in
toluene with light of wave length 3130A (maximum absorption of
the carbonyl group) yielded benzophenone as the major
photoproduct35. The p-iodo and o-bromo compounds were found by
Baum and Pitts to be most reactive while the p-bromo isomer was
of intermediate reactivity.35 Photolysis of p-halomethyl-
benzophenones also resulted in carbon-halogen bond homolysis.
The isolation of dimer III as the secondary photoproduct of
p-chloromethylbenzophenone in benzene is indicative of this
(Scheme 4).40 The mode by which the energy pumped into the
carbonyl group, using 3130A light, traverses the aromatic ring-
to reside in the carbon-halogen bond and ultimately shattering

it remains unknown.

 

._. (m;

The general trend of greater ease of carbon-halogen bond
cleavage for the series: C-I > C-BR > C-Cl >>> C-F is well

established with bond strengths:42

!' l J'd l l 3. . !'o 1 J: J
Ph-I 64
Ph-Br 80
Ph-Cl 95
Ph-H 110
Ph-F 125

Even though the photochemical cleavage of the carbon-
halogen bond is well known, there are no measurements of the
rate of carbon-iodine bond homolysis. The purpose of this
research is to determine the rate constant of the cleavage of
iodine from iodobenzophenone in various solvents.

In order to determine rate constants of carbon-iodine bond -
cleavage, quenching experiments using naphthalene as a triplet
quencher, were performed on both m- and p-iodobenzophenones.

The solutions for the quenching experiments were prepared
with constant concentration of either iodobenzophenone isomer,
an internal standard and varying quencher concentrations. The
solutions were then irradiated with 3650A. The resulting
Photoproduct concentrations were then used to determine the
ratio of quantum yield of product formation in the absence
Versus in the presence of quencher. .

This ratio of product quantum yields when plotted as a
function of quencher concentration gave linear Stern-Volmer
Iflots. From the slopes the lifetimes of the excited triplet
State and therefore the rate constant of carbon-iodine bond

Cleavage can be determined.

RESULTS

RESULTS

The photochemistry of m- and p-iodobenzophenone (m-IBP
and p-IBP, respectively) was studied in various solvents.
These solvents included cyclopentane, cyclooctane, a
methanol-ethanol mixture (9:1 ratio by volume), a
t-butylalcohol-ethanol mixture (8:2 ratio by volume),
acetonitrile and carbon tetrachloride. The ethanol in the
methanol-ethanol mixture prevented the shattering of the Pyrex
culture tubes during the free-thaw-pump degassing process.

Irradiation of both ketones in cyclopentane, cyclooctane,
methanol-ethanol, t-butylalcohol-ethanol and acetonitrile
resulted in the formation of benzophenone (BP) as the major
photoproduct. This indicates the loss of iodine from the
aromatic ringl4’15 possibly forming a BP radical (IV).

0
O

Trapping of this radical occurs due to its ability to
'abstract hydrogen atoms from a neighboring hydrogen donor
‘molecule.14'15 Cyclopentane, cyclooctane, methanol-ethanol and
the ethanol in t-butylalcohol-ethanol all served as excellent
hydrogen donors. Acetonitrile is an aprotic solvent therefore

“‘Octanethiol was used as a hydrogen donor. Thiols are well

11

12
known for their ability to trap radicals by donating their
hydrogen atoms.43v44 In carbon tetrachloride the loss of
iodine from the aromatic ring still occurs as indicated by the
production of diatomic iodine. The major photoproduct is the
corresponding chlorobenzophenone (ClBP).
SEW

Irradiation of m- and p-IBP in cyclopentane at 3650A gave
rise to two photoproducts, one identified as BP by l.c.
retention times and by GCMS analysis. The other photoproduct
was identified as iodocyclopentane, IC, by GCMS analysis.

The ketone solution remained clear colorless after
irradiation indicating the absence of diatomic iodine.
Formation of hydrogen iodide and the expected benzopinacol was
not observed.

Mass balance of BP formation in all solvents studied for

both IBP isomers was greater than 95%.

“a W6

m“: p-IBP

 

The quantum yield of BP formation (039) in cyclopentane
fr°m~n-IBP is identical to that from p-IBP, 0.277 and 0.274
respectively (Table I). The qu values of the two ketones
Obtained from the slopes of linear Stern-Volmer plots were

considerably different. The quenching of m-IBP in cyclopentane

13
gave a qu value of 259 (Figure 1) while that for p-IBP gave

3.01 (Figure 2).

Tabls_11 Quantnm_xislds_9f_benz9nhsngns_f2rmatign_at_11395

in_xariou§_solxsntsl

Sglxsnt £2152. 2:182.
acetonitrile 0.122 ' 0.506.
cyclopentane 0.277 0.274
9:1 methanol-ethanol 0.366 0.302
carbon tetrachloride 0.0497* 0.0661*
cyclooctane 0.0520 ' 0.0822
8:2 t-butanol-ethanol 0.0866 0.203

* quantum yield of chlorobenzophenone formation

Irradiation of m- and p-IBP in the more viscous
hydrocarbon, cyclooctane, also gave BP as the major
Photoproduct.

The value of 93p for the two ketones was much lower than
the values obtained in cyclopentane. In cyclooctane ’BP for
m-IBP is 0.0520 and 0.0822 for p-IBP. The qu value for p-IBP
in cyclooctane, 5.03, is larger than that obtained in
°Y°1°Pentane (Figure 3). In contrast to p-IBP, the qu value
of Ill"IBP is significantly smaller in cyclooctane than in

cyclopentane (kqf 260.5) (Figure 4) s

14

 

 

 

10.0
8.0 r' e
e
6.0 —
e
fig-2. __
°BP
4.0 w
///////’
2 s O /.
1.0
1 k--_ l 1
o 0.01 0.02 0.03
[Naphthalene], M
Flgure 12 (Table 1) Stern-Volmer plot of m-iodobenzophenone

in cyclopentane

15

oo.~

 

mcmucmmoHo>o aw 0:0:02Q0uson
Iopofllm mo muoHQ Hmaao>nsumum fie use n moanmav

E ._®:wamzuzmm2_

om.o . Geno Oq.o
_ _ _

.m muaofim

a...

l.c.n

 

16

. A . v mcouoooaoeno
:a can AmHHV osmuchoH0>o :fi waocmnmo~smnoco«

0.0

 

In no muoHQ umaao>lsumum Am p20 e mannav .n musme
z.._ocmfimcuzaoza
00.. 00.0 00.0 00.0 0~.0
fl _ a _ _

 

 

17

10.0 ——

 

 

l l J
0.0 0.01 0,02 0.03

[Naphthalene], M

Flgura 4. (Tables 1 and 2) Stern-Volmer plots of p-
iodobenzophenone in cyclopentane (. ) and in
cyclooctane ( E] ) .

18
o - o a -b - o

Irradiation of m- and p-IBP in the alcohol solvents also
gave BP as the major photoproduct. The solution remained
clear colorless. Diatomic iodine was not observed.

In methanol-ethanol cap is quite similar for both the meta
and para isomers. For m-IBP “BP is 0.302 while for pIBP 63p is
0.366. In t-butanol-ethanol the 03p value for p-IBP 0gp
underwent a small decrease to 0.203, while for m-IBP 03p
underwent a more drastic decrease to 0.0866.

The qu values for m-IBP decreased from 141 in.
methanol-ethanol to 79.2 in t-butylalcohol-ethanol (Figure 5)
while for p-IBP there was no significant change in the qu
values when irradiation was carried out in these two alcoholic
solvent mixtures. The qu value is 3.28 for p-IBP in
methanol-ethanol and 4.16 in t-butylacohol-ethanol (Figure 6).
E ! '! 'J

Irradiation of m- and p-IBP were also carried out in
acetonitrile; n-Octanethiol served as the hydrogen donor. The
major photoproduct was BP. The ketone solutions remained clear
colorless after irradiation indicating the absence of diatomic
iOdine.

The effect of the added thiol on the photochemistry of
the tWO ketones was observed. The concentration of the thiol
needed to maximize 43p was determined (Tables 13 and 15, Figures
7 and 8) and used in the actual quenching studies. The maximum

Values of 03p for the two ketones were very different, 0.122 for

19

.Hocmsumlaosonyma Hum :« GnocmsmoNcmnopofi
us no 0000 umsao>acumum 10 can 0 menses

z .Imamsmguzaazi
000.0 000.0 000.0

.m musmwm

 

T! y _ . _ — .

 

 

0.0a

20

.100 8550-80.33-» ~20 5
can A.v Hocmnumnaoconuma Hum :0 0:0:930559250

 

in no muoHQ umEHo>ncumum ANA use Ha mannav .m ousmflm
z .mocmamzucaoz_
0nm.0 ., - 00~.0 .. 0n~.0 00w.0 0m0.0 0.0
_ _ _ . _ _
0.~
e an
0 I10
mm.v
mu
.0
nu
mu
a.
mu
0 2

 

21

.maauuwsoumom :0 0cocmnmo~smnopofi
IE aouu ososm£Q0ucmn mo sofiumshom mo mama» 559:053
0:0 no 000:» 00000 no 000000 0:0 100 000090 .0 000000

z . 30200800095

 

 

 

 

000.0 000.0 000.0 000.0 000.0 0
fl 0 _ _ .
L mogu
0
mm
V O
1 00.0
liolxlllfi 1.0\\o
O .1
l mfigu

 

ON.O

22

.mafluuwcoumom :0 0cocmcmoNcmn0000|Q Eoum
meccmnmoNcmn mo codumEHOM mo pamwx Esucmsq
000 no 00000 00000 00 000000 000 100 000000 .0 000000
z .FaoflnumcmuOCa;0
0m.0 0m.0 0_.0

 

_. I _

 

0...

mm

23
the meta isomer and 0.506 for the para.

The qu values obtained from the quenching experiments
were so small, 1.23 for m-IBP and 1.67 for p—IBP as to suggest
that quenching of the two ketones was not occurring.
Qa:h9n_§§IIa§h12Iid§

In the previous solvents irradiation of both isomers of
IBP resulted in the formation of BP while in carbon .
tetrachloride the appropriate ClBP was formed. The presence
of ClBP was confirmed by g.c. retention times and GCMS
analysis. Mass balance was greater than 95%.

A color change in the ketone solution upon irradiation,
clear colorless before irradiation to clear purple after
irradiation, confirmed the presence of iodine. The iodine
concentration was monitored on a UV-Vis spectrophotometer at
iodine's wave length of maximum absorption, 5140A.

Hexachloroethane, C2C15, was also formed upon irradiation
Of IBP in CC14 and identified via g.c. retention times and GCMS

analysis.

Naphthalene quenched the formation of ClBP and I2.

0 ' o
hv m + 12 + 02015
CC14 ‘
c
I l
m-, p-IBP m-, p-ClBP

Quenching of the two ketones in carbon tetrachloride gave
linear Stern-Volmer plots (Figures 9 and 10) with qu values of

157 for m-IBP and 4.83 for p-IBP. The quantum yield for m-CIBP

24

m~0.0

000.0
_

.mpwuoHnomuumu conuso :0
0cocm£90u:000000lfi no uon umaao>lcumum A00 mannav

z ._0:0000000020

n00.0
0

000.0
—

m~0.0
0

.0 mhsmwm

0...

0.H

|.0.~

n.0.m

1.0.0

 

25

.060000:owuumu :00000 :0

 

0:0:0:QON:000000IQ mo u00m 00:0o>l:umum Aom 000090 .00 003000
2 ..0c000:000020
00.0 0~.0 m0.0 00.0 no.0 0
0 _ A 0 _
\\\\\\V.0.~
O O
0 m0..-
we
0
u.0.~
O

 

0.0

26
formation from m-IBP is 0.0497. The Qp value for p-CIBP
resulting from the irradiation of p-IBP is 0.0661. These Op

values are quite similar to the 93p values obtained

in cyclooctane.

 

Two degassed solutions of 0.0196M iodobenzene (TB),
0.0150M BP and 0.00925M n-pentylbenzoate were irradiated at
3650A for two hours each. Both samples remained clear
colorless after irradiation. They were both analyzed by GCMS
and found to contain all starting compounds with no

photoproducts observed.

DISCUSSION

DISCUSSION

W
The photoreactions of both m-IBP and p-IBP are identical

in all solvents employed. BP is the major photoproduct.
Photoreduction of the carbon-iodine bond results in all the
solvents except in carbon tetrachloride where the aromatic
iodine is exchanged for a chlorine, producing the
corresponding CIBP.

The relative responses of the two isomers to the changes
in solvent viscosity and polarity are remarkably different.
Quenching studies of p-IBP using naphthalene as the triplet
quencher show a steady increase in qu values, the slope of
linear Stern-Volmer plots, with increasing solvent viscosity
(Tables II and III). This trend suddenly falls off in the
eXtremely highly viscous t-butanol-ethanol solvent mixture.

Wagner and Kochevar have reported the decrease in kg, the
diffusion-controlled quenching rate constant, with increasing
solvent viscosity.45 An increase in qu values with increasing
Solvent viscosity, as in the case of p-IBP (Table III)
reflects an unexpected increase in r, the lifetime of the
reaCting excited state. Despite its varying value, para's 1
still remains small, on the order of 10’9s. The reaction rate

constant, kr (= 1/1) is approximately 109s‘1.

28

29

 

Tabis II Vissgsity 9f tns vaziggs sglvents.ii
figlzsnt Visggsity, c2
acetonitrile 0.345

t-butanol 3.316

carbon tetrachloride 0.965
cyclooctane 2.1621
cyclopentane 0.439

ethanol 1.078

methanol 0.5506

While p-IBP's triplet lifetime shows a strong sensitivity
to solvent viscosity and at the same time is nearly completely-
unresponsive to solvent polarity, the meta isomer does not
display such a straightforward trend in its photobehavior.

The effect of solvent viscosity on m-IBP's triplet
lifetime appears to be non-existent until viewed within the
context of solvent polarity. The triplet lifetimes of the
meta isomer are comparable in the solvents of similar polarity
but which have varying viscosities. In the polar solvents,
t-butylalcohol-ethanol and methanol-ethanol 1 are identical
despite the fact that the former solvent is nearly five times
more viscous than the latter. The same can be said for r of
m-IBP in the non-polar solvents, cyclopentane and carbon
tetrachloride, even though carbon tetrachloride is over twice
as viscous as cyclopentane. This relation falls apart in the

case of the heavy nonpolar solvent, cyclooctane, where 1 is

30

.mq mucoummmu .0

.mo sm.~rulmso.3.~.o +_Amsm.m.m.o usuwmooma> mumas mssao> sh wusuxae mum an .n

.mo mom.o nimno.fies.o + .womm.ocm.o "summooma> wows; mesao> an musuxaa Hua m .m

 

mam.o o.mH
o~.H ¢.qH
man.o m.v~
oo¢.o N.~H
mam.o o.nm
mmH.c HHH.o
mmHum mmHus
manofl .»

 

o~.v ~.ms
mo.m m.om
mm.¢ ems
m~.m Has
Ho.m mom
hm.~ m~.H
mmHnm. mmHus
2 box

Hnl

vv.o

av.c

mvw.o

omm.o

Hmm.o

OH.H

 

.mmumum omufioxm uoamfiuu mo mmfiwummwa tam mosam>

w

x

hm.m
mvma N
mom.o
mom.o
mmv.o

mvmvm.o

baocmsumuaosooamasusbnu
manuoooaowo
mofluoHcomHumu conuoo
mHocmnuMIHocmnumE

occucmmoHoao

maaunwcoumom

 

m0 .mufimoomfi>

v

.mmsHm> h x no mumEEom c

 

mucm>aom

.HHH manna

31
much smaller than in the other two non-polar solvents. Meta's
triplet lifetime is dependent only upon solvent polarity, a
greater value for 1 being observed in nonpolar solvents than in
polar solvents.

Quenching studies of both IBP isomers in acetonitrile
using a thiol as a radical trapper43v44_resulted in an almost
horizontal Stern-Volmer plot suggesting the inability of
naphthalene to quench the triplet in this solvent.

The efficiency of product formation from the photolysis
of the para isomer shows a general decrease with increasing
viscosity of the five lighter solvents (Figure 11, Table I).

In the heavier t-butylacohol-ethanol solvent mixture 9 displays
a marked increase. The meta isomer displays a similar trend,
except for the lowered Q value in acetonitrile. Within a
particular type of solvent, i.e. alcohol mixtures vs.
hydrocarbons, the viscosity dependency of for both isomers
holds true.

These results indicate the initial formation of a radical
pair, a BP radical and an iodine atom within a solvent cage.
The increase in solvent viscosity increases the time the
radicals spend in their cage by hindering the rate at which the
radicals diffuse from their cage and consequently react with
the solvent to form the photoproduct. This encourages incage
recombination which ultimately results in the rapid
deactivation of the excited triplet state to the ground state

accounting for the low 9 values in solvents of higher

32
'3,‘ V {1 - C9! 1! . . t 3.9-..df!’ P. Q -1 2'7

kr=1/1, 107 sec"1

 

§leent EleP 2:132
acetonitrile 901 658
cyclopentane 3.70 319
methanol-ethanol 5.81 250
carbon tetrachloride 4.12 134
cyclooctane 6.94 83.3
8:2 t-butanol-ethanol 5.56 106

viscosities (Scheme 5). Solvent polarity does not influence
the 0 values, thereby ruling out the possibility of the
involvement of an ionic intermediate in the photolysis of IBP's
carbon-iodine bond. Any photoproduct resulting from
nucleophilic trapping of an ionic intermediate was not

observed.

§shems.§
o

O O hv 1 isc. 3
t» K* I: K*

recomkl o {h o

 

 

 

 

33

.xufimooma> ucm>~om mo cowuocsu a mm A At v
0cocmnmoNcmnooowlm can A Ow 0cocmzmo§umnovofl
IE Eouu coauoahou Gnocmnqo~cmn mo moamwa asucoso .HH «upmwm
. do .xuflmoomfl>

o.~ o;

 

_ _

m . o

 

o~.o

o~.o

om.c

ov.o

om.o

om.o

34
. C - o d

Irradiations of IBP's were carried out at 3130A, the
absorption maximum of the carbonyl chromophore and at 3650A, a
wave length where naphthalene does not absorb.

Both the 1-1* transition involving the benzene ring and the
n-a* transition, the lowest lying of the carbon-iodine bondlo,
are improbable. The absorption maxima lie at 2540A for the
former transition and in the region of 2600-2800A for the
latter. Neither transition allows for the huge differences
between the reactivities of the two isomers, para being up to
78 times more reactive than meta. -

The IBPs have n-r* lowest triplet excited states. An 3nfw*
is reported for the unsubstituted, fluoro, chloro and
bromobenzophenones47 and is expected for the iodo analog.

Scheme 6 explains the great difference in reactivity
between the para and meta isomers but does not sufficiently

describe the mechanism of energy transfer through the ring.

0

O O h. :11” Maggie
3x*——~[W:“-J

 

 

35
Irradiation of the unsubstituted BP and 18 in

cyclopentane at 3650A, a wavelength where 18 does not absorb,
is expected to yield the "alkoxylike" biradical (IV). This
biradical, through abstracting a hydrogen atom from a
cyclopentane molecule, would form the semibenzopinacol (I) and
cyclopentyl (CP) radicals. Production of iodocyclopentane (IC)
can occur only through the abstraction of an iodine atom from
IB by a CP radical. The resulting benzene radical (V) is left
to abstract a hydrogen from the

O.

V

solvent thereby generating additional CP radicals. In the
actual experiment IC and benzene were not observed, indicating
the CP radical's inability to abstract an iodine atom from 18
and therefore IBP.

Even though the mechanism by which the energy pumped into
the carbonyl group traverses the aromatic ring entering into
the carbon-halogen bond, thereby breaking it homolytically,
remains unclear, abstraction of the iodine from the aromatic

ring by a solvent molecule is not involved.

EXPERIMENTAL

EXPERIMENTAL

E !' i E °E° !i E :1 . J
$213303

Asstgnitriis43: Reagent grade acetonitrile (EM
Industries, Inc.) 1800ml and 23ml benzoyl chloride was placed
in a two liter round bottom flask and refluxed for one hour.
This was distilled nearly to dryness into a two liter round
bottom flask containing 23ml water (to hydrolyze any.
benzoylchloride carried over).

Sodium carbonate (45 grams, 0.425 mole) was added,
refluxed for two hours and distilled. To this was added
anhydrous sodium carbonate (22.5 grams, 0.212 mole), potassium
permagenate (15 grams, 0.0949 mole) and then distilled. The
distillate was slightly acidified with concentrated sulfuric
acid, decanted from the precipitated ammonium sulfate and
distilled on a 92 inch column. Approximately 80% of the
acetonitrile was collected. The distillation was repeated on
this central cur and approximately 80% of this was collected.

fisnzsns49: Thiphene free benzene (Fischer Scientific
Company), 3.5 liters were purified by stirring over
concentrated sulfuric acid (10% by volume) for 12 hours. The
sulfuric acid was removed via a separatory funnel and another

Portion added and stirred for a similar period of time. This

37

38

was repeated until the sulfuric acid layer no longer turned
yellow after stirring. The benzene was washed repeatedly with
distilled water (3x300ml), then saturated with sodium
bicarbonate (2x300ml). The benzene was then washed with
distilled water (3x300ml) and dried over magnesium sulfate
overnight. It was filtered from the magnesium sulfate,
refluxed for 12 hours over phosphorous pentoxide (about 10
grams phosphorous pentoxide per liter of benzene) and then
distilled through a one meter column packed with stainless
steel helices. Approximately 10% of the benzene was discarded
as the forerun and 70% collected from the column.

;;fig§ang15°: t-Butanol (Mallickrodt Chemical Company),
500 ml was first dried by stirring over magnesium sulfate. It
was further purified by adding magnesium powder (0.5 gram,
0.0206 mole) and iodine (0.05 gram, 0.000394 mole) and then
distilling through a 45cm column packed with glass helices.
The central cut was redistilled to insure the absence of iodine
in the distillate.

ac ' e: (Fischer Scientific) Similar

purification method employed for benzene but on a smaller
scale. .

stiggstans: (Aldrich Chemical Company, Inc.) Similar
purification method employed for benzene but on a smaller
scale.

gysigpsntggs: (Eastman Kodak Company) Similar

purification method employed for benzene but on a smaller

39

scale.

Etha39151: "Absolute" ethanol was further dehydrated by
reacting with magnesium ethoxide, prepared by placing clean
dry magnesium turnings (5 grams, 0.206 mole) and iodine (0.5
gram, 0.00394 mole) in a 2 liter round bottom flask, followed
by 50 to 75ml absolute ethanol. The mixture was warmed until a
vigorous reaction occurred. When this abated, heating was
continued until all the magnesium was converted to the epoxide.
Up to 1 liter absolute ethanol was added, refluxed for an hour
and then distilled off. Approximately 70% dried ethanol was
collected from the column.

flsxags: The hexane used (EM Industries, Inc.) for l.c.
analysis was purified by similar purification method employed
for benzene but on a smaller scale.

ustnangi: Methanol (EM Industries, Inc.) was purified by
adding magnesium powder (2 grams, 0.0823 mole) per liter of
methanol and distilling through a 45cm column packed with glass
helices. Approximately 70% purified methanol was collected
from the column.
Internal_§tandards

Ethylbsnzsstssz: Ethylbenzoate (Matheson, Coleman and
Bell) was washed with 2 M sodium hydroxide and then shaken
with calcium chloride. It was dried with magnesium sulfate
and then vacuum distilled. The central cut of approximately

70% was collected.

40

usthyibsgzoate: Reagent grade methylbenzoate (Matheson,
Coleman and Bell) was vacuum distilled and approximately 80%
was collected.

n;2sntyibsnsgs§s53: Synthesized and purified to greater
than 99.5% purity by Royal Truman.

n:flgnyibsnggats53: Synthesized and_purified to 100%
purity by Royal Truman.

W

n;gs§gnsthigl: n-Octanethiol (Aldrich) was vacuum
distilled and the center cut (90%) was collected. .
911mg:

Naphtnaisns: The naphthalene (J.T. Baker Chemical
Company) used in.the photochemical experiments was purified by
repeated recrystallizations in cyclopentane followed by
sublimation (experimental m.p. 78-80°C; literature mp.p.
80.55°C).

,teu- a * ‘-. in _2- "g-g ". at'-; o- - . ot-o odu ts
fisnzgphsngns: The benzophenone (Fischer Scientific) was

purified by repeated recrystallizations in cyclopentane

(experimental m.p. 46-47.5°C; literature m.p. 48.1°C).

Wm“: The m- and p-
chlorobenzophenone were synthesized by Royal Truman.

Ethyisns_giysglz The ethylene glycol (Mallinckrodt) was
taken directly from the bottle.

fisxgghigrgsthans: The hexachloroethane (Matheson, Coleman

and Bell) was taken directly from the bottle.

41

Iggins: The iodine (Fischer Scientific) was taken
directly from the bottle.
amnesia

Synthesis of m-iodobenzophenone (m-IBP) by Friedel-Crafts
acylation: A solution of the appropriate iodobenzoyl chloride
was prepared in a 100ml three-neck round bottom flask fitted
with a dropping funnel, reflux condenser, thermometer, and a
magnetic stirring bar from iodobenzoic acid (3.72 grams, 0.015
mole) in 15ml chloroform with Sml thionyl chloride added
dropwise. The solution was heated to 509C for three hours and
then left to stir at room temperature for approximately 12
hours. The excess thionyl chloride was removed by diluting the
reaction mixture with cyclohexane and placing on an aspirator.
The solvent was evaporated off on a rotovap.

Benzene, 25ml and anhydrous aluminum chloride (2.00
grams, 0.015 mole) were placed in a three-neck 100ml round
bottom flask fitted with a dropping funnel, condenser,
magnetic stirring bar, and a thermometer. The mixture was
cooled to about 5°C in an ice bath and the crude acid chloride
made above was slowly added with much stirring. The mixture
was warmed up to 50° slowly, left to stir for four hours and
quenched with 30ml cold water followed by Sml dilute
hydrochloric acid. The organic layer was separated and the
aqueous layer washed with diethyl ether. The ether and organic
layers were combined and washed with 5% sodium bicarbonate.

The ether and benzene were removed on a rotovap. The crude

42
product was either vacuum distilled to give a yellow oil in the
case of o-IBP or column chromatography on a silica gel column
using ethylacetate- hexane as an eluent followed by
recrystallization in ether pentane solvent mixture as in the
case of m-IBP.
m-IBP: 70% yield. m.p. 39-400 C. us m/e 308(44%), 231(19),
203(10), 181(9), 105(100), 77(62).

Elemental analysis: 50.68%C, 5.19%0, 2.94%H and 41.19%I
calculated for formula C13HQOI; found for m-IBP 50.90%C and
2.33%3. .

The IR spectra were taken in both CCl4 and C82. m—IBP's
spectrum is compared with that of m-BrBP55 in Tables V and VI.-
The region of m-IBP and BP's spectra from 1,000 to 600 cm"1

taken in C82 are given in Figures 12 and 13, respectively.

 

19a
19b

14

9a
15
18b
183

12

17a

17b

103

11

6b

 

vC-C
vC-C
VC-C
vC-C
BC-C
C-hal.
fiC-H
fiC-H
fiC-H
fiC-H
Ring
YC-H

YC-H

YC-H

YC-H

X-sens.

YC-H

aC-C-C

1588W

1565m
1468mw
1419m
12728h
1290m
293w

1149m

1069m

954m
910m
898m

808m

756w
748m

778m

669m

664

1580mw

1448m
1315m

1305m

1178m

1149m
1085VW

1027mw
999mw

988VW

973VW

927W

847vw

716s

763vw

695m

617vw
sh

1600m
1560m 1575mw
14703h
1415m" 1450m
1320m
1310m
1150m‘ 1180m
1150m
1075w
1065mw 1030w
1000mw
950m
910mm
975vw
810mw 930sh
850w
715vs
745m
780m
695m

44

 

Igpis V, (ggn§,)
Assignmgnth 33- . 3'Br . 3'1
6a x-sens. 578m,br 540m,br
16b X-sens. 475m 440m
168 ¢C-C 425m 404w
flC-hal. 249w
‘YC-hal. 189W
pc0¢ 150w,br 220w
‘YCO¢ 134m

a. When for a vibrational mode two frequencies are given, those
listed in the first column refer to the halo-substituted
ring. Frequencies linked by brackets belong to different
conformers.

b. Both Wilson notation and approximate description of the

motions are given.

I§h13_21‘ ' 0 0.- 'uoqau'o ! ‘ an- e' u’: 09- an!

00-:0 ”Q. Q

'_,'-’°.'_°;O 9.9-9.!“ 9

 

ngpgnnd C80 C-C(O)-C 3990 7C=O fflC-C-C
3Br- 1670vs 1267s 639m 528vw 374m
,946m
1257ms
3I- 1665vs .1270vs 640m
,945ms
1260s

a. frequencies linked by bracket belong to different
conformers.

45

Microns

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

- '0
.II III-
sH”-
.U' !.Iu0. I all '
I'lll!'|.l...- I
I I

 

 

 

 

 

 

 

l
q .
. .
4Hu'lv'i'lnlllyn l'l III-luvl'llI-I.
h p o

 

‘... '1

er

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1‘ '0
'l
Iiil II
11
F e rli!
alllnlll >| -l“--lll|.l§l|l.|
.
'tillll'lll. [y'l'll III: 'l'o‘l-.ll‘ O 'IIIIII
P II?

 

 

 

 

.
f. I -III'IJ alvll O'I'i'ilo.

 

"L'u- n.’.!lllll" 8 I,
.

 

 

 

 

 

 

 

 

 

 

 

 

il’l ll «‘IIIIII' nlIl-Il'l'll'l
nllll[r
‘ "Illt'i I III'III'IYI'II Io'|'
. a .
'1'1‘ll‘l’ If... |
. o
1!-.3 ‘0‘-
P — lt"1l. . lull...

 

 

 

 

 

 

 

 

 

L _ a

1+

‘Jrrl’ I "I‘ll in

L w e

606

800

1000

Wavenumbers, cm-l

IR spectrum of m-iodobenzophenone in CS2.

Figure 12.

 

600

 

 

 

 

 

 

 

 

46

 

Microns

 

l

 

CIT!

 

 

 

 

 

L01

“ “n“ .' I'lc I , Il| ' -0: y-

a

Y. . 30, ,“- IIIIIIII". 0 l

UNI: v ...|...r|Ilo+|uilX..;..lll.-|u .. .. u-
“ hm . )nrlt'IIISI'lro. .JT.

(I.
lib..- a ro‘l'.a| a
. .
I... I

 

 

(\-

 

800

 

 

 

 

 

 

 

 

Wavenumbers,

 

 

'i- I-

IR spectrum of benzophenone in CS2.

 

.. V III-1|.l... . . o I > up .0 . In. I.
l,o. .l' .'.I||.I 'q '1 :I‘I III to ILT'OIJWIC'. ‘T Inll'1-Ill’lf' . I I: .nl . 0 I I u n‘ . ll
fill.‘ I ll'.|.'l||ln._0 'i'fi" I,l'l'. .IIO lt.||l0l"u » . em .usl 0. lo I... I. f- . ta 1. l
. . . . . fl . . .
6' |.I|Il'l I .l I lll’ll. ." 1". +0': 1 IIWI ’IID'I 0". lLtTl'}!!! . 'T'u'llll'... ‘.'l|l.|l| 11'! . Ii.lr.lu ,. i
. c . b . (PP

 

 

 

 

00""?! I‘ll-5,-..l- I III-llll -. II

Figure 13.

47
1H NMR (coc13) 6 7.22(t,IH), 7.49(t,2H), 7.6l(t,lH),
7.77(t,3H), 7.92(d,1H), 8.13(s,lH).

No reliable sample of m-chlorobenzophenone was available
therefore the 1H NMR spectrum of m-IBP (Figure 14) was compared
to that of the unsubstituted BP (Figure 15) and the published
spectra of monosubstituted halobenzenes.

The 1H NMR spectrum obtained for BP under the same
conditions as that of m-IBP gave 6 7.48(t 4H), 7.59(t 2H), and

7.81 (d 4H) while a published 1H NMR spectrum of BP gave:56

nam st c assisnment

benzophenone a c O C a.(4H) 7.53
/’ la

b c c.\\ .b b.(2H) 7.61

a a c.(4H) 7.83

The published spectrum of BP matches nicely with the
experimental one establishing the assignments of the peaks in
the latter spectrum. The peaks at 67.48(4H) are due to the meta
protons, at 6 7.59(2H) are the para protons and at 6 7.81(4H) are
the ortho protons.

In m-IBP's 1H NMR spectrum the protons on the
unsubstituted ring give rise to peaks that bear a strong

resemblance to BP's 1H NMR spectrum:

I d O c
1’ | a
9'\~ e C b

f a

13 NMR p—ipg 6, ppm p.32 BP 6, ppm J. 52

7.92 (d,lI-I) 3.70
c 7.77 (t,3H) 7.08 7.81 (d,4H) 7.00
5.43
b 7.61 (t,1H) 7.30 7.59 (t,2H) 7.73
7.30 _. 6.95
a 7.49 (t,2H) 7.73 7.48 (t,4H) ‘7.68
7.03 6.95
7.22 (t,1H) 7.78

The remaining peaks in m-IBP's spectrum are the result of the
protons on the substituted ring.

Introduction of a halogen into one of the aromatic ring
causes both para- and diamagnetic shifts of the protons as seen
in the published spectra of some monosubstituted halobenzenes
(Table VII). Iodine causes the largest effect on the protons
of all three halogens. The protons ortho to the iodine are
shifted downfield while the meta protons are shifted upfield.
The para protons remain essentially uneffected.

The two most downfield set of peaks in m-IBP's 1H NMR
spectrum result from the two protons ortho to iodine. The
isolated ortho proton (d) situated between iodine and the
carbonyl group gives rise to the singlet at 6 8.13 (1H) while
the other proton (g) results in the doublet at m 7.92 (1H).
The proton para to iodine (e) gives a signal superimposed upon
that due to the ortho protons on the unsubstituted ring (c).
This is the cause of the apparent triplet at 6 7.77 (3H). The
proton meta to iodine (f) gives a triplet at 6 7.22 (1H). The

doublet at 6 7.32 is probably due to unidentified impurities.

49

ectra of some sim le

 

We. a .1
s st'tu

DQEQ §§I§Q§B§§

chlorobenzene57

bromobenzene58 b

08

 

iodobenzene59 c a.(2H) 7.09 ppm
a b.(lH) 7.30 ppm
c.(2H) 7.70 ppm
Tapis_ylilp_ . v'o s ence s ect a of
n e es
Ultraviolet Phosphorescence
Spectraa Spectra
(maxima) (0-0 band)
n,x*
KQLQnge Amer epmax Krupp
benzophenone 346 60 41960
m-iodobenzophenone 347 106 418
p-iodobenzophenone 348 173 422
a” Amax in nm, 6 max in M"1 cm'l.

b. in 1:1 methanol-ethanol mixture at 77° K; irradiated at

3130 A.

en enes .

ass nment

a.(SH) 7.31 ppm

a;(3H) 7.00-7.30 ppm

b.(2H) 7.43 ppm

 

 

50

. .mza ow 0>fiucamu
mHUQU cw msocchoNcmnooofiua Ho Eauuommm mzz :H .ea musofim

.506 E 6
m6 . 0;. mg. 9m mam 0.6
¥l¥-l>lk‘ul\f IrrblLLfkrlelurLlnrurrfl M - 1 _ .isxflellkflrl .inxL’KPlelk

 

.17.,-;.-.,..,..% 31a

 

 

 

 

 

 

 

"‘\

 

 

 

 

 

 

 

 

51

.mzs on m>wumHou maoao :fl 0cocmcmo~con mo mzz ma

Ema o
6.8 of. 0.x

.mH ousoflm

o.m

 

 

W

 

 

 

52

 

 

 

 

 

 

 

c:
o
H
4.)
E‘
o
(I)
:2
% % :
3000 uooo 5000
Wavelength , in Angstroms
Figure 16. UV spectrum of m-iodobenzophenone in cyclopentane.

A = 3470A, 6(3470 A) = 106 M'l.
max

53

 

 

 

 

 

i i 3 i i !
3a00 3800 azoo asoo 5000 saoo

Wavelength in Angstroms

Figure 17. Phosphorescence spectrum of m-iodobenzophenone.

54

Synthesis of p-iodobenzophenone (p-IBP)°1: p-
Aminobenzophenone (2.75 grams, 0.014 mole) and 20ml glacial
acetic acid was stirred in a 100ml three-neck round bottom
flask fitted with a dropping funnel, thermometer and stopper.
The mixture was cooled to about 5°C in an ice bath. Sodium
nitrite (1.26 grams, 0.0183 mole) in 8.5ml sulfuric acid was
added dropwise. This was left to stir at 5°C for three hours,
then slowly warmed to room temperature followed by addition to
a 90ml ice-water mixture containing potassium iodide (3.35
grams, 0.0202 mole) and copper metal dust (0.19 gram, 0.0030
mole) in 14ml water. The mixture was heated to 60°C for one
hour or until all nitrogen gas evolution ceased followed by
treatment with 80ml 10% sodium sulfate. This was filtered and
the brown residue was recrystallized three times in hot
methanol. The product was further purified by column
chromatography on a silica gel column using ethylacetate-hexane
as the eluent.
p-IBP: 55% yield. m.p. 95-98°c. MS m/e 308(71%), 231(47),
203(15), 181(12), 105(100), 77(97).
Elemental analysis: 50.68%C, 5.19%C, 2.94%H and 41.19%I
calculated for formula C13390I: found for p-IBP 50.96%C and
2.74%H.
The IR spectra were taken in both CCL4 and C82. p-IBP's
spectrum is compared with that of p-BrBP62 in Tables IX and X.
The region of p-IBP's spectra from 1000 to 600 cm"1 taken in

C82 is given in Figure 18.

b . Eing_funQam_ntals_lsmé£1_gf_2:brem__and_n:
1349113.. e . 73,21;

 

Assigpppnth 4H- 4Br 4H- . 4':

8a vC-C 1600m 1588ms 1600w 1585s
8b vC-C 1531sh 1568sh

19a VC-C 1489Sh 1481mw 1480w
19b vC-C 1447m 1393mw 1450m l390mw
14 VC-C 1313m 1277s 1315m 12808

3 fiC-C 1303m 1295w 1310m - .

C-hal. 281w

9a BC-H 1178sh 1172m 1180mw,sh

15 fiC-H 1146w 1150w
18b fiC-H 10738h 1103w
18a fiC-H 1025w 1011m 1030w 1010m
12 Ring 999VW 738m 1000w 740mw
5 VC-H 99va 967ww 97va
17a YC-H 97Zsh 955w 955vw
17b VC-H 920m 829W 925m,br
10a VC-H 847sh 840m 840mw
11 YC-H 786m 790mw

1 X-sens. 724s 1068m 725ms 1060mw
4 ¢C-C 696s 682vw 700ms

6b aC-C-C 16vw 626w 625VW

56

Table_lxl lsentll

 

Assignment? 4H- . 4'Br 4H- . 4'1
6a x-sens.. 568w 465m 540m,br
16b X-sens. 465m
16a ¢C-C 403mw
fiC-hal. 263mw
C-hal. 215w
fiCO¢ 175mw
C0¢ 109m,br

a. When for a vibrational mode two frequencies are given, the _
first refers to the 4-substituted ring.

b. Wilson notations and approximate description of the motions
are given in the first and second columns, respectively.

Vibration 12 becomes x-sens. in the p-substituted ring.

 

W 0 -‘° "Jean?! ._ ‘ 01!!-- 0’ 9‘9,°!I.° :10. 0-
OAQOCLQ oo,*,o.;7 .. 0; 2,0; 0 00-30 ”U. Q

ngpsnnd C=0 C-C(0)-Q BC=0 YC=0 flC-C-C

4Br- 1667VS 1267ms, 937m 654m 350VW

4I- 16658 1270ms, 940mw 650mw

57

Microns

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

.
.Itlvll . llnlllll+.lv|..|— I'll. I!.o..lo|.ln I7..II||I."I,II|'III I-
I!L|I..-.. IIILIIIIS 1.. .II- I. .. -.
o o
'o x

I; .l‘tvl 'TI. .IU‘IIIIIDIW..I..II.I7I||¢

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

600

800

1000

1

cm

Wavenumbers,

IR spectrum of p-iodobenzophenone in C82.

Figure 18.

58
1H NMR (coc13) 6 7.8 (d of d, 4H), 7.6 (t, 1H), 7.5 (t, 4H).
The 1H NMR spectra of p-IBP (Figure 19) closely resembles that
of p-CIBP (Figure 20). In both spectra a quartet appeared
downfield at 7.8 ppm (4H) relative to CHC136 7.25 ppm.63 This
quartet corresponds to BP's ortho protons which occur at 7.81
ppm. In the case of p-IBP, the iodine causes the ortho protons
on the substituted ring to resonate slightly downfield to the
ortho protons on the unsubstituted ring. Chlorine does not
have such a pronounced effect; there the quartet at 7.8 ppm in
1H NMR for p-ClBP resembles less a doublet of doublets. The
small triplet at 7.6 ppm (IE) is due to the lone para proton in
both p-ClBP and p-IBP since BP's para protons occur at 7.59
ppm. The meta protons in the para substituted BPs gave rise to
a triplet at 7.5 ppm (43) which corresponds to BP's meta
protons at 7.58 ppm. The singlet at 6 7.25 ppm is due to the
lone proton in CHC13.
n ' ' a s
The stock solutions of the ketone with standard were
prepared by weighing out the required amount of ketone and
internal standard into a volumetric flask and filling to
volume with solvent. Individual flasks for the quenching runs
were made up by pipetting an equivalent amount of stock
ketone-standard solution into numbered 5ml volumetric flasks
containing the required amount of quencher and filling to

volume with solvent. The solutions were then injected into

59

.mza 0» 0>wumH0u

mHUQU ca mcocmcmoN:00ooofiIQ no asuuommm mzz :a .ma musmflm
.EQQ 5” c
m.o o.~ m.> o.m m.

w
FLI¥IFIWKFLI#IFKFk{klleLileLlFlleLI>lFlfL

JJ j
x

 

 

 

 

 

 

 

 

60

 

 

 

 

 

 

L
‘h4—*—LA—+—~4CJ—*—CA_A_LJCA_A
8.0 7,5 7.0

Oingmm,

Figure 20. 1HNMR spectrum of p-chlorobenzophenone in CDC13
relative to TMS.

61

 

 

Absorption

 

 

l ' g .
I
3000 0000 5000

wavelength in Angstroms

Figure 21. UV spectrum of p-iodobenzophenone in cyclopentane.
A = 3480 A, e (3480 A) = 173 m‘l.
Imax

62

 

 

 

 

l 1 l L l 1 l

I r I I I I 1
3600 0000 0000 0800 5200 5600 6000
‘Wmmflemgxxinlkgstnmm

Figure 22. Phosphorescence spectrum of p-iodobenzophenone.

63
separate constricted 100x13mm Pyrex or Kimax culture tubes
using 5ml hypodermic syringes with 6 inch needles, filling
each tube uniformly with 2.8 ml. The culture tubes were
previously cleaned by boiling in soapy distilled water
' overnight followed by at least four rinse cycles in boiling
distilled water. v

The ketone solutions were degassed by attaching the tubes
to a vacuum line over No. 00 one-hole rubber stoppers on
individual stopcocks. The solutions were slowly frozen in
liquid nitrogen, then a vacuum was applied for several
minutes. The samples were allowed to thaw and the cycle
repeated. After the fourth freezing and evacuation, the tubes.
were sealed off with gas-oxygen torch.

All volumetric pipets and flasks used were class-A
volumetric ware. They were cleaned in the same manner as the
photolysis culture tubes were.

Irradiation for quantitative analysis were performed in a
"merry-go-round" apparatus with a Hanovia 450-W medium
pressure lamp contained in a water-cooled quartz immersion
well. Corning 7-83 glass filters were used to isolate the
3650A line and a 1cm path of 0.002 M potassium chromate in 1%
aqueous potassium carbonate was used to isolate the 3130A
line.

- e 8
All quenching experiments employing cyclopentane,

cyclooctane and carbon tetrachloride as solvents were carried

64
out according to the procedure previously described.7 The
cyclopentane and cyclooctane solutions were analyzed by HPLC,
while the carbon tetrachloride solutions were analyzed via g.c.

In order to obtain the large range of quencher
concentrations found in all of the experiments of p-IBP, it was
necessary to weigh naphthalene into each individual 5 ml flask
separately.

Irradiations in carbon tetrachloride resulted in a
pronounced color change from clear colorless before irradiation
to clear deep purple indicating the formation of iodine. The
iodine concentration was monitored on a UV-Vis
spectrophotometer. The wavelength of maximum absorption of
iodine in the visible region of the spectrum, 514 nm, was
determined by scanning both a solution of an irradiated tube
and a prepared solution of known iodine concentration in carbon
tetrachloride. The extinction coefficient, 6, was determined by
measuring the absorption at 514 nm of various iodine-carbon
tetrachloride solutions of known iodine concentrations. This 6
value, 833 M'lcm"1 was then employed in the calculations of
iodine concentration.

W

For irradiations carried out in methanol-ethanol solvent
mixture, the optimum solvent ratio was obtained by irradiating
both ketones in various alcohol mixtures. The ratio that gave
the highest °BP value for both ketones, 9:1 by volume, was then

employed in all experiments. The optimum t-butylalcohol-

65
ethanol solvent ratio, 8:2 by volume, was obtained in a similar
manner and used in all experiments.

After irradiation the alcohol solvent of each tube was
gently removed on a rotovap and replaced with purified benzene.
The solutions were then analyzed on HPLC.

n-Octanethiol served as the hydrogen donor in the
irradiations of both ketones in acetonitrile. In order to
maximize 93p, both ketones were irradiated in varying amounts of
thiol. With steadily increasing thiol concentrations, ’BP
values increased and then leveled off. The thiol concentration
at which 03p first levels off is then used in all experiments in

acetonitrile. The irradiated samples were analyzed by g.c.

 

The IB was vacuum distilled before its use in the
preparation of the samples. The refractive index, “200, of IE
and that of purified benzene, B, were measured to determine the
amount of B in IB. The nZOD were measured on a Bausch and Lomb

instrument. IB was found to contain no B before irradiation.

n20D
experimental literature

mg __v_al_u.e Jigs—

13 1.6187 1.6200

B 1.500 1.5011

The sealed tubes were prepared in the normal manner,
irradiated at 3650A for two hours and analyzed by GC/MS. No
photoproducts were observed. The irradiation of m— or p-IBP in

cyclopentane at 3650A for two hours would normally give

66
approximately 24 to 33 percent conversion of starting ketone to
BP photoproduct.

The g.c. trace of the irradiated sample is given in Figure
23. The mass spectra of each peak in the g.c. are given in
Figures 24 to 27. A benzene peak was not observed on the g.c.
trace.

The first peak of the g.c. trace, retention time (r.t.)
being 1 min. 20 s is due to the solvent. The second peak, r.t.
between 2 min. 34 s and 3 min. is the result of IB (Figure 24).
n-Pentylbenzoate gave the third peak, r.t. between 5 min. 10 s
and 5 min. 44 s (Figure 25) and BP the fourth peak, r.t.
between 6 min. 10 s and 6 min. 48 s (Figure 26). The last
peak, r.t. between 9 min. 20 s and 9 min. 52 s (Figure 27) is
due to the benzopinacol. Under similar conditions IC's g.c.

r.t. would be between 2 min. 18 s to 2 min. 46 s. (Figure 28).

67

.mcoucmmoH0>0 cw mamasmnonow 6:0 0coc0£moNcmn

no mamfimm 00u0flomuuw may no woman .0.0 0:9

2: 922 85 6:6 86
a8 . an an an 8.
F? p h _ _ _ p — . _ _ F p p L FL -

.mm musmflm

 

 

 

 

 

 

 

3m

 

 

 

 

.88.
55.

o- 3 8.10
03 E. — gum cum. «8“ .33

 

 

 

 

 

 

 

 

NES- Noo— "Hr-Cm

8.8.2 @23—
u:—

 

68

.Ammvom

.Amhvam .Asaves .Aooacss .Ammvsma .Aamovvom 0\8 m2
.mcmucmmoH0>0

cw unencmnboOH 0cm 0coc0cmo~smn mo mamamm

teamwomuufi 0:» ca econsonooow mo asuuommm mum: .qm musmwm

 

 

 

 

 

 

 

 

a... 6% 8. 8. 6:. 62 . 8 3 3 as.
_>L...»L r ...~.C._..Fp-+>+p_rr>...:._r.»»..pL.—»CLP».» w.>.hr. .LrIAWI . L.»
N». as_. 4 mm =q
8 e
. 1
es
4 l
1 r66»
1 .
xx
1
a
l v
A v
_
85 L -98.

\e
m_e - owzcsm om. op mm.
wp_«z mac. "wnazam
.mvmwk uu_¢ . n. ecu ".3¢u menu . eoumnun. mm\~.\o.
«e .mx: wmcm mm. noel "apes cam—Quam mmac

69

.onvam .Amavmm .Aomvos

.Amucss .Aooavmofl .Aoavmma ..»66.m~H 0\8 m:

.msmucmnoHo>o Cw

mcmncmnoooH 6cm msocanoNcmn no mansmm omumHUmuufl
. 0:» :w 0u00ucmnaaucmnuc uo asuuommm mum: .mm Gasman

 

 

 

 

 

 

 

 

 

s: as 02 so on .6 we
.. r...,-.-. .rL.7....I.... ..._ r... ....,-..,JvL. ...,..L,40 . .rL. pww.
d __z A»): _
A m. .
i an an .
. 2
l ..
l .n .
1 -85»
l m: f
k
A .
23. .1 as -682

 

 

fi._. 5 r.t.—ham “Nu. Oh find—n
9:5. ~03 fig.

.mmmnn .u_e m. qu ._4¢u vn.w . oc.~n.n_ m0\~.\o.
we. .wxz ”mam “6.. Noe. .cpco zauhuuem mmc:

70

.Amsvam .Aooa.>s

.Ammvmoa

.Awsmcmma 0\8 m:
.mcmucomoH0>0 ca samucmnooOM one 0:0:0390nc00 mo
coHumHoouHH may a“ 0cocchoNcmn mo asuuommm mum: .om musmwm

3—

 

 

 

 

 

8. 02 2.
r.»»..L. _ .p. ..—::.P»LL_: .. .pp»b..
_ A)
8.
. a:
;
.mmawm .u.¢ a. lag ...¢u
”5.02mfl. ne.es.eza

8 3 0.. w).

  

no.8

 

 

 

k . - [3.8—
82-208.2663 .. .
. Ezsux.m2:m
_86 42:83.25:a..
.sgfifimflr

71

..mm.ae .Amavam .Amsvsn .Aooavmoa .Awmovmma 0\8 m:
.mcsucmmoHomo :w 0:0ucmnop0w can 0cosmnmoNcmn
no Goduowomuum ecu cw Hooocfimncmn mo asuuommm mmm: .hm musmflm

 

 

 

 

 

 

 

 

8n own can an. 00— an ux:
—Lpb..».h.....P._pp._.r.....p.h.~p..s.p _.P._».»Lm_...
8 1
mu
2».
.1
1 10.9..
- -3
. fl: 1.
k .
.31 .
2: ,1. . . 03 . l.c.:—

. ammo .. 2 an. o... ammo

4 . - mtg «8. fig

.3: .0; 0. do :3 . 35 + 8.8.2 8x23.
we .3 mg aka. «8. .33 £88m uni

72

.3—

.mcocmnmoNcmnOGOMIQ
mo coducwoouufl mau.aouu ocwuasmmu manucmmoHoaoooofl

no mamamm.ooumfivmuuw :0 no 0000» .0.m one

 

.mm whamwm
E. 3.8 as. or... 82... as. 61.. Ba. 32... 2.... 6...... 2...... 9;.
3m. 3m. 6...... an 3.. 8. on... . 3m 68 8.” a... 8. 8
_____—..~pP~—bb___~_____L[—_______.__~—._>__pr_# wr________.p
. III-(I- III-[II ..I \II

 

—|}-/ T (at...

f
,.

7’ (0’
I
II.

(I!!- ..J.. at.
.(f {5 ”I.
/. l .

4 a
. 3.
.x i a K m w
/. A“ I
/ .
_
_
2a

 

! __..
l 1.

 

 

 

 

I If I. tofu.

_.

 

 

J
zwhzu

 

 

 

 

 

 

9.30.130
8mg.

Eh:efis.3&&u
a. 88. .38

8.8.3 33
o;

 

 

 

 

 

 

 

—p,...u

1fi
.m

 

73

Quantitative Analysis

All quantitative measurements of products and starting
ketones concentrations were done by internal gas and/or liquid
chromatography techniques. The standards used were
methylbenzoate, ethylbenzoate, n-pentylbenzoate, and n-
nonylbenzoate.

Response factors were calculated from standard samples of
the photoproducts and the starting ketones for both l.c. and
g.c. They were determined by measuring the relative.peak areas

of the standard and the compounds studied.

 

 

 

Compound (area of Compound)
Eq.1. ________ = RF
Standard (area of Standard) by l.c. and g.c.
[Compound] (area of Standard)
Eq.2. RF = x
[Standard] (area of Compound) by l.c. and g.c.

A good approximation is:

#C atoms in the Standard
Eq. 3. RF =

 

#C atoms in the Compound

where one counts each c-o and C=0 bond as 1/2 a C atom. RF
values were calculated for both g.c. and l.c. These values

are given in Table XI.

74

 

 

Table X1. Response fiagtoxs to; quantitative analysis on both
9;£:_2£Q_l121
compound; standard RF system
acetophenone: benzene 0.0729 l.c.
acetophenone: hexadecane 2.35 _ g.c.
benzophenone: n-pentylbenzoate 0.326 l.c.
benzophenone: n-pentylbenzoate " 0.955 . g.c.
benzophenone: benzene 0.0232 l.c.
benzophenone: n-nonylbenzoate 1.14 g.c.
n-octanethiol: n-pentylbenzoate 2.14 g.c.
ethylene glycol: methylbenzoate 14.2 g.c.
p-iodobenzophenone: benzene 0.00729 l.c.
p-iodobenzophenone: n-pentylbenzoate 1.33 g.c.
p-iodobenzophenone: n-pentylbenzoate 0.111 l.c.
p-iodobenzophenone: n-nonylbenzoate 1.28 g.c.
m-iodobenzophenone: n-pentylbenzoate 1.016 g.c.
m-iodobenzophenone: n-pentylbenzoate 0.314 l.c.
m-chlorobenzophenone: n-nonylbenzoate 1.04 g.c.
m-chlorobenzophenone: n-pentylbenzoate 0.62 g.c.
p-chlorobenzophenone: n-nonylbenzoate 0.762 g.c.
p-chlorobenzophenone: n-pentylbenzoate 1.19 g.c
hexachlroethane: n-pentylbenzoate 3.34 g.c.
hexachloroethane: ethylbenzoate 3.85 g.c.

75
The concentration of any compound can be determined by
g.c. and/or l.c.:

(area of Compound)
Eq. 4. [Compound] = RF [Standard]

 

(area of Standard)

: J J !' E : ! X. 1:

All quantum yields for the photoproduct formation or the
starting ketone disappearance were determined relative to the
acetophenone formation from valerophenone in benzene on
parallel irradiation of samples of equivalent volumes at
3130A. The quantum yield of acetophenone (AP) formation has
been determined to be 0.33 for valerophenone (VP) in benzene.
Conversion of VP was limited to 10%.

(area of AP)
Eq. 5. [AP] = RF [Standard]

 

(area of Standard) by g.c.

(area of AP)
Eq. 6. [AP] = RF

 

(area of Standard) by l.c.

where benzene serves as the standard.
From the concentration of AP, the amount of light

absorbed, Ia in einstein per liter, can be determined:

[AP]

 

Eq. 7. Ia =
0.33

76

The quantum yield of product formation, 4p, equals the
concentration of the product, [P], formed, divided by the

light absorbed, Ia:

-911.
Ia

Eq. 8 .p

The quantum yields of product formation from m-‘and p-IBP
in the various solvents are listed in Table XII.

The concentration of BP resulting from the irradiation of
m- and p-IBPs were calculated according to Eq. 4. The value of

O BP°/’BP was determined using the following equation:

939° , [BP]°
.BP [3?]

Eq. 9.

 

where ’BP0 and [BP]° are the quantum yield of BP formation and
BP concentration, respectively, in the absence of quencher. In
the presence of quencher 03p and [BP] are used.

According to the following equation64

Eq. 10 “o = 1 + kg? [Q]
o

the 43p°/ 93p values of each quenching run are plotted as a
function of [Q] to give a linear Stern-Volmer plot with a slope
equal to qu . The value of r is determined by dividing out the
known values of kg for the appropriate solvent employed. The
value of krr rate constant of carbon-halogen bond cleavage, is

set equal to 1/1.

77

m>n . .

 

vsm.o u 0 .
Hmm.o ov.~ 2 mmmoo o NH
nmm.o H.mv mm.H m~mo.o vm.~ .cfiE on 2 mvHo.o x
m>m
>>~.o n o .
mmN.o Hm.H z momoo 0 Ha
mm~.o H.mv mm.H mHmo.o mm.H .CHE on E mm~o.o x
mm
"mcmucwaoHo>o
z mmmoo.o m
oom.o mv.m vH.N vamo.o mm.m .cHE mw .u: H z mm~o.o mx
2 onhoo.o m
mm.~ HV.H wo.e Hmao.o mm.m .cfiE mm .uc H z nm~o.o mx
2 mmvoo.o N
mm~.o mm.H HH.m Hono.c mm.H .cHE om .un H 2 mm~o.o Hz
mm
"mawuuacoumom
0 z Camumcflm OH 2 oH ~_m¢H 2 OH maflu mcouwx uucw>H0m
at m ml ml m ammo m:
. H m« mono ._uospouoouocma cofluMApmuuH
vaccwnmoNconouoHnonm "mm
wcocmnmoNcmnouoHnole "Hm maneucmnaxcoclc um mmHIQ umx mcocchOuoom nmc
mcocwcmoNcmn "mm wumoNcmnaauchI: "a mmHIE flax 0cm~cwnum

.mumumeocfluom .2 o~.o. moccmLQOumHm> Eouu mono HmowEm£00uocm .HHx mfinmfi

78

 

ommo.o n o .
Homo.o vv.m z omHo o HH
mmvo.o w.ov vm.H va.o m>.H .uc m z MHNo.o x
mm
"mcmuooooao
m>m
Homo.o u o .
Hmeo.o . mo.m z ano o NH
Humo.o w.ov em.H va.o mm.m .un m z mmHo.o x
mm
nmeo.o um>mo
ommo.o mH.~ 2 mmHo 0 HH
mwvo.o o.ov em.H va.o mm.H .u: m 2 nHmo.o x
Ha
"mUHuOHnomuumuconumo
mom.o um>mo
Nm~.o I ov.H z mmmoo.o H
HHm.o mne.o mmH.o nHmoo.o mv.H .cHE OH 2 envoo.o Nx
m>m
oom.o u 0 . .
mmm.o m>.m z mmmoo 0 HH
omm.o no.H mmm.o mmvoo.o mo.v .CHE cm 2 nmmoo.o x
mm
"HocmcuolHocmnqu Hum
0 z chumcflm OH 2 0H ~Hm¢_ 2 OH mEHu mcoumx nucm>H0m
H: m ml mu m mono mu .
. H dd moum .Huospoumouocm_ :oHumHUmuuH

.HHX manmh

79

E MHHo.o H

 

mo~.o . vo.~ mem.o omzo.o 0mm.o .:32 we 2 memoo.o Ne
w .

memo.o u >mo z memoo 0 Ha

Hmmo.o m~.~ mmn.o «OHo.o mmH.o .:32 m3 2 ~mmoo.o x

z homoo.o H

oHao.o mm.~ mmh.o voH.o mo~.o .cae ms 2 evooo.o He
mm

“HocmcumlHocmusnlu mum

mmmo.o uw>mo z eoHo.o NH

mmho.o e.ov em.H emH.o ao.m .u; N z omHo.o x

z NmHo.o H

ammo.o oh.H omm.o manoo.o mma.o .cHs OH : mHHo.o we

0 z chumch OH 2 OH ~Hm<_ 2 0H mEHu occumx nucm>H0m
H- m m- m- m mmum m-

. H m< mmum .HuospouQOuonm_ :ofiumwpmuuH

.ucoo .HHX THQMB

80
Identification of Photoproducts

The photoproducts resulting from the irradiation of m-
and p-IBPs in the various solvents were identified via GCMS
analysis of the actual quenching experiments. Their mass
spectra were compared with that of the actual compound stored
in the library of the GCMS (Figures 29 to 37). The mass
spectra of BP, m- and p-CIBP, and C2C16 were contained in the
library while IC's spectrum was not.

The peak at m/e 41 in IC's mass spectrum (Figure 32) is
due to the +CH2CH=CH2 fragment while the 69 peak is the result
of the cyclopentyl radical. The monatomic iodine gives the 127
peak while the 196 peak, the parent peak, is the

iodocyclopentane cation.

81

.AchHm .oncne .AooHcmoH .AmmvmmH .Awmcmap m\5 m:
.mcocmcmoNcmnooowlfi mo coHHMflomuuH

 

 

 

 

 

 

 

may Eoum mCHUHSmmu mcocmcmoNcmn mo Enzuommm mmmz .mm musmflm
can am. ew_ co. oNH co. om am a? ax:
>F...Lp:. 7...»:..—.r>..r.r.H..»L.L.Lr+L._. .rh..r-..£.CL.»LL:..H.»LL.FE_:..
. . mm_ _;_ mm_ -_ m__ mm mm mm __ mm ow
um
mmH
in
l N” 1
1 Y.e.on
mm“
cover 1 mos H.o.oo_
am_. - mm..
mh_¢3 “mum “wnazqm
.ommmm uu_m m. Jag "~3qu m_um . oousnum_ mm\_.\_a

WOH "ma: mmqm mmH. «Hmmm «cbqo tjahuumm mmct

€32

.HHmva .Homvbh

 

 

 

 

 

 

 

.AooHcmoH .AwmmcmmH m\e m:
.wcocmcmoNcwnonowlm mo cofiumapmuufl
vso Eouw mcHuHsmmu mao:vcmo~cmn m) Esuuommm mam: .om musmflm
eon . em” . on” am. as. mm m :
Jurrt-_-t..~-t-_r_»pL.p._._rr wiu-»«_»L PLLT$.»1.?L .41
471 cm“ ac. mm_ 1 we" 34 mu. .d m._ mm mm A. mw _ ‘3;
m2 - n
m...—
# f
NwH Hm
1 ,.a.on
I “a r
A ,
L ..
94cmw 1 ma. ..o.oo1
mw_. - mmm.
mc_q: ammm_ amalgam
.moo_~_ "u_m m. Sac ”.3qu mmua + ooummue_ mm mo 49
9.: a. : umzm a... 3......“ 2:3 rdsmam m3:

HuiHm .Hbmvhb .HoovaoH .memVNmH m\E v.2
szoo man no aumunHH

83

 

 

 

 

 

 

may Eouw.Um:Houno mcocmnaoNcon mo Esuuommm mmmz .Hm musmflm
8. a: omH mm 3 nu).
. :1. b'r .1!>» )ibfldz . q». t
- - - H
. .. \ c
.016 o H . .o
l a. .
32$
58.
. -szmxaagozcxgtmg
N2 “.2; 92:68
mofiuxc mmcm 31 £2.5qu 35o 53mm E333

83

.AthHm .Ahmcee .AoOHCmoH .AwmmcmmH m\5 a:
«mzoo may no ammunHH

 

 

 

 

 

may Eoum.©mcflmuno mcocmzmoNcmn wo EsuuoQO mmmz .Hm musmflm
co. om. av. o~_ oo_ so am
r, L] + , :1.r].1 {.,---:. ,. ........ .. --. , LirfifiH». .-r -:
-\ a - -H; .n a... p u
. -Syzuxa_o.uzozqumc“maazam
NmH ~.»:.z o.o_:.mHu
:umqwm >a¢am~4

moHuu\: mmcm nmvH umz>a¢amH4 “chco

u4.$3m

 

rcooH

.Amvcmm .AooHcHe .Aoorcmm .AmchmH .AwmcemH m\5 m:
.mcosmnmoNcmnoooHIm mo coflumflcmuuw may
Scum baauasmmu mcmucvaoHowooooH Mo Eduuommm mmmz

 

 

 

84

 

 

 

 

m5“ mam; . m1.»— msé an— ”S”; cum ”3.» an. m. r.
<...Lr- _-.-.mn-»._r»»»r+>-._-..-_--.r—.>}»_--.r_t».h.-. prr»_?.[$FF,_...._.r.
— . meal— »..1: :4 H_ m: _: me mm. 7w mr. _ __ .. ._.: __ q
n...
Ame 3_ u e
_
l T Qdm
l r
L v
1 1
mm. “7 I o ”'3'“.
mm; .. mm.
erz 6me "minim.
.mcmwmm "Sm ms .30 "—449 mvum + «Simona— wwxmwxzw
mm "m .: wmrm mm. own: "3&0 Eachumdm mmnt

85

.Aomvmm ~HoovaoH

AchHH .AmmcmmH .AHHchH .iwwpcmHm «\2 m2
.QCOCGSQONCTQOGOHIE HO GOHHMHUMHHH ma“ EOHM

 

 

 

 

 

 

 

 

@CHJHUWQH MCOCGEQONCQQOHOHSUIE MO EDHHUMQW mmmz .MM QHSmHL
0mm . com mnH aw. an mxz

Hb>.»..w_»pr_ru.a_._-L.__purr...r —»..L3Pr.»—.r

mm A _%H as _ H a a P
NnH
l T
HmH MNH
HHH
1 . R 1
mm—
1 I008
mfim

L r

mmmmm L 8. [9.8.

mmm. I owzzzm mmmu o» ona
w—qu MHmmH ”mudram

.omHNm uuHm mu Ado «Hgau mHnHH + oeuvounH mmxHN\_H
mo. umxz mmam mmm. mHmmH ua—qo ::m»umdm mm¢:

.Hoovhh .HOOHVmOH
.HhNVHHH .HmevaH .HOHVHmH .Homvon m\E m:

.mzoo on» no >HmunHH

on» Eoum.mcocanoNtmnouoHnole mo Esuuommm mmmz .vm musmwm

owm 02 an: a:

F n n b h

an H 3 H oo 8

 

 

 

86

 

 

_ __: -_ _. 7..

.
v
e u v
.
. I
. I I
. .
.
.

 

 

 

 

. exam
:52

 

 

. u4>zwld3>zmxdomofuumv ”.5qupr "gem
. 40.96165
75¢de 58:

Enucué
mo_um\z “mam .va "mz>m«mm_3 u¢bco

 

87

 

 

..mmcee .AooHcmoH
.AmNVHHH .AmncmmH ..chHmH ..mmmcmHm m\e m2

.mzuw man no ammunHH
on“ Eoum mcocwnaoNcmncloHconm mo Esuuommm mmmz

.mm musmflm

 

 

 

 

 

 

 

 

9% 8. 8. a: 02 . 9”,: 2.. 8
it. b b tA—rlq r b» a —. » >b ) r» ri Pb) —> f— P —)r buw h — )|.p|? .. bw —
, -szwagzwaomoeoqt .593G:.9&$ -
ma 25.: . 46.992:
8. mi umqm :2 Sign: .28

:umqwm 53.3 .H

88

.HoOvam .Hmmvhm .Hmmvhv ..mmvme .HHNme .Hthm
.onvmm .vavvm .HHmvem .Homvmm .HemvnHH .AmmvaH
.HmNVHNH .HmvaH .HhVHmH .HvHVvoH .HmvamH
.HmvmmH .HmvaHH .HmmvHom .mevaom m\8 m:
.mcocmnmoNchOUoHnm mo :oHuwHomuuH ecu

Eoum @cHUHsmmu mcmnumouoHcowxmn mo Esuuommm mmm: .mm muomwm

mm. mm. o.. o”. _ . am am a. u\=

.m mm mm mm

3.

 

c.3—
om. I 09.23 8: Pp mm:

. . mtg 38— ”a;
$88 .31 no 43 :3 :3 + 8383. nonmem—
nn fix: wmam B: 3mm— .SS 5&5me mmfi.

89

um m

 

 

 

 

 

 

 

 

 

 

 

 

. tmmmemd n4 maneu:
ans - mmazu
- » 4. - m:m.mono- _ .
1m._ 2 ' . _ ' . .-.‘- - * '
and “
h o l. - > '

‘ - -

; 3| H '

AL I- 1 . . - . V - ;. - .
‘IE so so zoo :29 :40 :se :30 239

Figure 37.

Mass spectrum of hexachloroethane ootained from
the library of the GCMS.

MS m/e 203(64%), 201(100), 199(61), 168(21),
166(43), 164(33), 131(9), 129(9), 119(98),

117(100), 96(31), 94(20), 84(10), 82(16), 59(6),
49(5), 47(15)-

90
s t 'o

The two ketones, M-IBP and p—IBP were identified and
characterized using a combination of the following
instruments.

Proton magnetic resonance spectra at 250 MHz were
recorded on a Bruker WM-ZSOMHz Fourier Transform Nuclear
Magnetic Resonance Spectrophotometer. All chemical shifts
were reported in parts per million (ppm) down field from
tetramethylsilane (TMS).

The ultraviolet absorption spectra were measured in 10mm
cells on a Varian Cary 219 Spectrophotometer, courtesy of Dr.
Chang. Cyclopentane served as the solvent. All extinction
coefficients, 6, in the solvents used in the photochemical
experiments are reported in units of 14"1cm"1 on Table XIII.

The phosphorescence spectra of both m-IBP and p-IBP were
performed on a Perkin-Elmer MPF-44A fluorescence
Spectrophotometer attached to a Perkin-Elmer 150 Xenon power
supply. The emission spectra were recorded on a Perkin-Elmer
recorder. A solution of 0.001M p-IBP in a mixed solvent of
methanol-ethanol (1:1 ratio by volume) was placed in a curved
bottom nmr tube. The tube was carefully inserted into a liquid
nitrogen-filled, quartz window Dewar flask and placed in the
cell chamber of the spectrofluorometer. The sample was
irradiated at 3130A and the emission scanned from 3600 to
6000A. The emission spectra were recorded. A solution of

0.001M m-IBP was treated in a similar manner. The emission was

91

Table XIII. Extinction Coefficients

 

 

 

e M.1 cm.1 6 M-1 cm-1
compound/ solvent (3130 A) (3650 A)
p-iodobenzophenone
benzene 182 91.2
carbon tetrachloride 139 63.1
cyclopentane 162 78.5
cyclooctane 191 ‘ 86.0
acetonitrile 247 82.3
methanol 531 75.6
ethanol 441 75.3
t-butylalcohol 340 60.9
m-iodobenzophenone
benzene 21 63.7
carbon tetrachloride 79.4 69.5
cyclopentane 115 43.1
cyclooctane 164 69.6
acetonitrile 108 58.1
methanol 401 47.4
ethanol 375 46.5
t-butylalcohol 389 46.4
benzophnone
benzene 78.4 47.9
carbon tetrachloride 86.5 56.0
cyclopentane 61.4 40.7
cyclooctane 71.4 47.8

92

Table XIII. (cont).

 

 

 

e M-1 cm-1 6 M-1 cm-1
compound/ solvent (3130 A) (3650 A)
acetonitrile 101 36.1
methanol 122 26.1
ethanol 116 ' 28.7
t-butylalcohol 112 ' 19.5
naphthalene
benzene 35.4 0.401
carbon tetrachloride 24.9 1.94
cyclopentane 14.2‘ 0.00
cyclooctane 22.8 4.04
acetonitrile 21.4 0.968
methanol I 22.8 4.02

ethanol 21.2 4.13

93
scanned from 3400 to 5600A and recorded.

Infrared absorption spectra of m-IBP and p-IBP were
recorded on a Perkin-Elmer 599 Infrared Spectrophotometer.
Carbon tetrachloride was used as the solvent. All absorptions
are reported in wave numbers (cm'l).

Melting points were taken on a Thomas Hoover capillary
melting point apparatus. All melting points are uncorrected.

Elemental analysis of m-IBP and p-IBP were performed by
Spang Microanalytical Laboratory, Eagle Harbor, Michigan,
49951. '

All mass spec and GCMS were recorded on a Finnigan 4000
GCMS by Ernest Oliver and later by Richard Oleson. After
irradiation the ketone solutions were analyzed by GCMS. The
spectra of the photoproducts were compared to the mass spectra
of the actual compounds stored in the library of the Finnigan
4000 GCMS.

A11 analysis for product formation was performed on
either a gas chromatograph or on a liquid chromatograph. The
g.c. used were Varian Aerograph Model 1200 and 1400 gas
chromatographs fitted with a 5 ft. by 1/8 inch column for an
on column injection and containing 5% SE30 on Chrom W. Peaks
were recorded on a Leeds and Northrup recorder and areas
measured on an Infratronics CRS 309 digital integrator. The
l.c. used was a Beckman Model 332 high performance gradient
liquid chromatograph attached to a Perkin-Elmer LC-75

spectrophotometric detector. An Ultrasphere Si 5 pm 4.6 x 250

94
nm column was employed at a constant temperature of 35.1°C and
eluted with a 98.5:1.5 hexane-ethylacetate solvent mixture at a
flow rate of 1.5 ml/min. The area ratios of the product and
starting ketones relative to an internal standard were

measured by a Hewlett-Packard 3380A digital integrator.

TABLES

96

 

Table 1. Quenching of 0.0186 M m-iodobenzophenone in
cyclopentane at 3650 A.
S1= 0.0109 M n-pentylbenzoate
BP= benzophenone
Q= naphthalene
Irradiation time= 20 min.
area BP mole BP _4 '
[Q], M area Sl mole S1 [BP], 10 M esp/931,
0.00 0.190 0.0620 6.77 -
[0.00 0.192 0.0627 6.85 -
0.00 0.183 0.0597 6.52 -
0.00431 0.0923 0.0301 3 29 2.04
0.00862 0.0564 0.0184 2.01 3 34
0.0129 0.0417 0.0136 1 48 4.54
0.0172 0.0328 0.0107 1.17 5.74
0.0215 0.0294 0.00958 1.05 6.39
0.0259 0.0235 0.00766 0.834 8 05
qu= 265

Standard HPLC conditions; detector wavelength set at

270 nm.

97
Table 2. Quenching of 0.0191 M m-iodobenzophenone in
cyclooctane at 3650 A.
S1= 0.00800 M n-pentylbenzoate
BP= benzophenone

Q= naphthalene

Irradiation time= 2 hr. 7 min.

 

area BP mole BP _4
[Q], M area S1 mole S1 [BP], 10 M 0gp/ QBP
0.00 0.374 0.122 9.77 -
0.00 0.279 0.0910 7.28 -‘
0.00423 0.294 0.0958 7.67 1.11
0.00846 0.201 0.0655 5.24 1.63
0.0127' 0.198 0.0645 5.15 1.66'
0.0169 0.151 0.0493 3.40 2.51
0.0212 0.137 0.0445 3.57 2.39
0.0212 0.136 0.0443 3.54 2.41
0.0254 0.136 0.0444 3.55 2.40
0.0254 0.136 0.0444 3.55 2.40
k T: 60.5

q

Standard HPLC conditions; detector wavelength set at
270 nm.

98

 

Table 3. Quenching of 0.0149 M p-iodobenzophenone in
cyclopentane at 3650 A.
Sl= 0.00705 M n-pentylbenzoate
BP= benzophenone
Q= naphthalene
Irradiation time= 16 min.
area BP mole BP _ .
[Q], M area 51 mole S1 [BP], 10 05P/ QBP
0.00 0.246 0.0803 5.66 -
0.00 0.250 0.0816 5.75 -
0.0769 0.194 0.0633 4.46‘ 1.28
0.149 0.199 0.0648 4.57 1.25
0.297 0.142 0.0463 3.26 1.75
0.519 0.110 0.0360 2.54 2.25
0.670 0.0859 0.0280 1.97 2.90
0.819 0.0739 0.0241 1.70 3.36
0.889 0.0515 0.0168 1.19 4.79
kq7= 2.86

Standard HPLC conditions; detector wavelength set at

270 nm.

99

 

Table 4. Quenching of 0.0150 M p-iodobenzophenone in

cyclopentane at 3650 A.

Sl= 0.00672 M n-pentylbenzoate

BP= benzophenone

Q= naphthalene

Irradiaiton time= 18 min.

area BP mole BP _4
[Q], M area S1 mole S1 [BP], 10 M QEP/ ’BP
0.00 0.383 0.125 8.37. '-
0.00 0.374 0.122 8.21 -
0.0758 0.302 0.0983 6.61 1.25
0.151 0.242' 0.0789 5.31 1.56
0.300 0.209 0.0680 4.58 1.81
0.675 0.121 0.0393 2.64 3.14
0.800 0.0917 0.0299 2.01 4.13
0.846 0.149 0.0485 3.26 2.54
0.891 0.0923 0.0301 2.02 4.10

k T = 3.19

Standard HPLC conditions; detector wavelength set at

270 nm.

Table 5.

1

100

= 0.00834 M n-pentylbenzoate
BP= benzophenone
Q= naphthalene

Irradiation time= 26 min.

Quenching of 0.0149 M p-iodobenzophenone in
cyclooctane at 3650 A.

 

area BP mole BP _4
[Q], M area S1 mole S1 [BP], 10 M ’gP/QBP
0.00 0.205 0.0667 5.56 -
0.00 0.206 0.0671 5.59. -
0.0593 0.182 0.0592 4.93 1.13
0.0877 0.175 0.0570 4.76 1.17
0.152 0.151 0.0492 4.11 1.36
0.300 0.158 0.0514 4.29 1.30
0.551 0.209 0.0681 5.68 0.983
0.703 0.0798 0.0260 2.17 2.57
0.753 0.0690 0.0225 1.87 2.98
0.753 0.0712 0.0232 1.94 2.88
kq = 2.45

Standard HPLC conditions; detector wavelength set at 270 nm.

101
Table 6. Quenching of 0.0152 M p-iodobenzophenone in
cyclooctane at 3650 A.

S = 0.00758 M n-pentylbenzoate

1
BP= benzophenone
Q= naphthalene

Irradiation time= 29 min.

 

area BP ‘mglg_§g _4

[Q], M area S1 mole 81 [BP], 10 M QfiP/QBP
0.00 0.152 0.0497 3.77 -

0.00 0.142 0.0462 3.50. -

0.0783 0.126 0.0411 3.11 1.17
0.154 0.0880 0.0287 2.17 1.67
0.303 0.0690 0.0225 1.71 2.13
0.531 0.0337 0.0110 0.832 4.37
0.687 0.0280 0.00913 0.692 5.25
0.826 0.0439 0.0143 1.09 3.34
0.893 0.0525 0.0171 1.30 2.80

Standard HPLC conditions; detector wavelength set at 270 nm.

Largest concentration of Q at which considerable quenching
occured is 0.687 M.

102

 

Table 7. Quenching of 0.00593 M m-iodobenzophenone in

9:1 methanol-ethanol at 3650 A.

Sl= 0.00944 M n-pentylbenzoate

BP= benZOphenone

Q= naphthalene

Irradiation time= 42 min.

area BP mole BP _
[Q], M area S1 mole S1 [BP], 10 05P/ éBP
0.00 0.254 0.0829 7.83 ;
0.00407 0.254 0.0828 7.82. 1.00
0.00611 0.158 0.0516 4.87 1.61
0.00815 0.0874 0.0285 2.69 2.91
0.0122 0.134 0.0436 4.12 1.90

= 65.5

Standard HPLC conditions; detector wavelength set at

270 nm.

103

 

Table 8. Quenching of 0.00552 M m—iodobenzophenone
in 9:1 methanol-ethanol at 3650 A.
Sl= 0.00636 M n-pentylbenzoate
BP= benzophenone
Q= naphthalene
Irradiation time= 12 min.
area BP mole BP _4
[Q], M area 81 mole 81 [BP], 10 M ’EP/QBP
0.00 0.0871 0.0284 1.18 -
0.00 0.0893 0.0291 1.85 -
0.00185 0.0718 0.0234 1.49 1.23
0.00370 0.0666 0.0217 1.38 1.33
0.00555 0.0675 0.0200 1.27 1.44
0.00740 0.0564 0.0184 1.17 1.56
0.0110 0.0469 0.0153 0.973 1.88
Standard HPLC conditions; detector wavelength set at 270 nm.

104

 

Table 9. Quenching of 0.00608 M m-iodobenzophenone
in 9:1 methanol-ethanol at 3650 A.
Sl= 0.00791 M n-pentylbenzoate
BP= benzophenone
Q= naphthalene
Irradiation time= 13 min.
area BP mole BP _4
O
[Q], M area 81 mole S1 [BP], 10 M. QBP/eBP
0.00 0.0666 0.0217 1.71 -
0.00 0.0669 0.0218 1.73 -
0.0112 0.0328 0.0107 0.843 2.04
0.0156 0.0215 0.00707 0.554 3.10
0.0325 0.0110 0.00357 0.283 6.08
0.0487 0.00433 0.00141 0.111 15.5
0.0644 0.00396 0.00129 0.102 16.9
k T = 141
q

Standard HPLC conditions; detector wavelength set at 270 nm.

105

Table 10. Quenching of 0.00579 M m—iodobenzophenone in
8:2 t-butanol-ethanol.

Sl= 0.00602 M n-pentylbenzoate
BP= benzophenone
Q= naphthalene

Irradiation time= 21 min.

 

area BP mole BP _4
[Q], M area 81 mole 81 [BP], 10 M egp/esp
0.00 0.126 0.0410 2.47 -
0.00 0.131 0.0428 2.57 - -
0.00374 0.103 0.0337 2.03 1.24
0.00921 0.0693 0.0226 1.36 1.85_
0.0108 0.0742 0.0242 1.45 1.74
0.0321 0.0380 0.0124 0.747 3.37
0.0526 0.0251 0.00817 0.492 5.12
k 7 = 79.2

Standard HPLC conditions; detector wavelength set at 270 nm.

106
Table 11. Quenching of 0.00484 M p-iodobenzophenone in
9:1 methanol-ethanol at 3650 A.

S = 0.00402 M n-pentylbenzoate

1
BP= benzophenone
Q= naphthalene

Irradiation time= 20 min.

 

area BP mole BP _4
[Q], M area S1 mole 51 [BP], 10 M ¢8P/¢BP
0.00 0.203 0.0662 2.66 - .
0.00 0.200 0.0651 2.62 ' -
0.0320 0.171 0.0556 2.45 1.08
0.0457 0.163 0.0530 2.33, 1.13_
0.0978 0.147 0.0479 1.92 1.38
0.169 0.129 0.0419 1.68 1.57
0.228 0.117 0.0382 1.53 1.73
kg? = 3.28

Standard HPLC conditions: detector wavelength set at 270 nm.

107

Table 12. Quenching of 0.00481 M p-iodobenzophenone in
8:2 t-butylalcohol-ethanol at 3650 A.

Sl= 0.00441 M n-pentylbenzoate
BP= benzophenone

Q= naphthalene

Irradiation time= 20 min.

area BP mole BP

 

[Q], M area 51 mole 31 [BP], 10' M *89/‘889
0.00 0.140 0.0456 1.86 r
0.00 0.132 0.0430 1.90 -
0.0209 0.115 0.0374 1.65 1.14
0.0488 0.102 0.0331 1.46. 1.29
0.0922 0.0920 0.0300 1.32 1.42
0.174 0.0706 0.0230 1.01 1.85
0.215 0.0782 0.0255 1.12 1.67

= 4.16

Standard HPLC conditions; detector wavelength set at

270 nm.

108

 

Table 13. The effect of added thiol on the photochemistry

of 0.0185 M m-iodobenzophenone in acetonitrile

at 3130 A.

82: 0.00496 M n-nonylbenzoate

BP= benzophenone

thiol= n-octanethiol

Irradiation time= 1 hr. 30 min.

. area BP mole BP _3

[thiol], M area 82 mole 52 [BP], 10 M [QBP
0.00 0.207 0.236 1.17 .0.0756
0.00 0.184 0.210 1.04 0.0674
0.0183 0.280 0.319 1.58 0.102
0.0392 0.311 0.355 1.76 0.114.
0.0677 0.322 0.367 1.85 0.120
0.145 0.334 0.381 1.89 0.122
0.187 0.346 0.395 1.96 0.126
0.246 0.361 0.411 2.04 0.132

Standard g.c. conditions; column temperature= 180°C.

Table 14.

109

Quenching of 0.0188 M m-iodobenzophenone in the

presence of added thiol in acetonitrile at
3650 A.

Sz= 0.00569 M n-nonylbenzoate

BP= benzophenone

Q= naphthalene

thiol= n-octanethiol

Irradiation time= 26 min.

area BP mole BP

 

 

0.122

0.122,

0.122
0.122
0.122
0.122

0.122

[thiol], M [Q], M area 82 mole $2 [BP],-10.3 M QEP) ’BP
0.00 0.552 0.629 3.58 -
0.00 0.550 0.627 3.57 -
0.0228 0.715 0.815 4.64 0.770
0.0421 0.504 0.575 3.27 1.09
0.0875 0.582 0.664 3.78 0.946
0.158 0.458 0.522 2.97. 1.20
0.217 0.505 0.576 3.28 1.09
qu= 1.23

Standard g.c. conditions; column temperature= 190°C.

110

Table 15. The effect of added thiol on the photochemistry
of 0.0186 M p-iodobenzophenone in acetonitrile
at 3650 A.

82= 0.00386 M n-nonylbenzoate
BP= ben20phenone
thiol= n-octanethiol

Irradiation time= 1 hr. 25 min.

 

. area BP mole BP _3

[tthl], M area S2 mole 52 [BP], 10 M ’BP

0.00 0.352 0.401 1.55 ,0.238
0.00 0.347 0.396 1.53 0.235
0.0200 0.494 0.563 2.17 0.335
0.0499 0.576 0.657 2.53 0.391
0.0839 0.745 0.849 3.27 0.505
0.194 0.631 0.719 2.77 0.427
0.238 0.526 0.600 2.31 0.357
0.277 0.738 0.841 3.24 0.500

Standard g.c.

conditions; column temperature= 170°C.

111

Table 16. Quenching of 0.0185 M p-iodobenzophenone in the
presence of added thiol in acetonitrile at
3650 A.

SZ= 0.00514 M n-nonylbenzoate
BP= benzophenone

Q= naphthalene

thiol= n-octanethiol

Irradiation time= 45 min.

 

Standard g.c. conditions; column temperature= 170°C.

. area BP mole BP _3
[tthl], M [Q], M area 82 mole 82 [BP], 10 M..Q§P/QBP
0.109 0.00 0.208 0.237 . 1.22 -
0.109 0.00 0.208 0.237 1.22 -
0.109 0.0961 0.197 0.225 1.16 1.05
0.109 0.190 0.184 0.210 1.08 1.13
0.109 0.376 0.104 0.118 0.607 2.02
0.109 0.655 0.0974 0.111 0.573 2.13

112

 

Table 17. Quenching of 0.0186 M m-iodobenZOphenone in

carbon tetrachloride at 3650 A.

S1= 0.00501 M n-pentylbenzoate

P1= m-chlorobenZOphenone

= naphthalene

Irradiation time= 13 hr. 7 min.

area P1 mole P1

-—————— -———-—- -3 a
[Q], M area S1 mole S1 [P], 10 M QPI/ 0P1
0.00 1.82 1.39 6.98 ~ -
0.00736 1.33 1.01 5.05 1.38
0.0147 1.04 0.795 3.98 1.74
0.0289 0.648 0.494 2.43 2.88

k T = 54.0

Standard g.c. conditions; column temperature= 190°C.

113

.esva an cououacoe .e
.2 vovo.o ma cousooo mcasocosv news: no a no cofiuouucuocoo unwound

.U.oomH luuauouomsou :Edaoo «msoauwccoo .o.m unaccoum

 

 

hmH u tux
om.H mm.m mq.o 66.5 SMH.o 88H.o mmmo.o
mH.m mo.H Hmc.o «H.H mH~c.o «awo.o 664°.o
mv.~ om.H. 85H.o on.H mm~c.o «Hmo.o Hsmc.o
em.m Hm.H HmH.o Hm.H cnm°.o mmqo.o mh~o.o
5H.n s~.~ amH.o mc.n mmmo.o one°.o maHo.c
me.~ 6H.~ omH.o nm.n m-°.o Hmac.o humco.o
. «5.6 mmm.o ~.8H 88H.° mv~.o 58.8
. nm.m s»~.o nH.m 66H.o aH~.c oo.o
Ha Hm N N H H H
o\ .0 oH .H H. 66H m6 :oHuauomn< x 618H .H a. m «Hos m 6096 2 .Ho_
Hm «Hos Hm noun

.4 omwm an mowuoHnoouumuconueo cw chGoAQoNsmnocoHIE z ca~o.o mo mcncucoao

.cHs 8H .0; a uoaHu :oHuuHeouuH
«swooH In

«coHenusmuc no
ococonmo~coaouoHcan IHA

ouaouaoanucomuc z memoo.o uHm

.mH «Hogs

114

 

Table 19. Quenching of 0.0149 M p-iodobenzophenone in

carbon tetrachloride at 3650 A.

Sl= 0.0149 M n-pentylbenzoate

P2= p-chlorobenzophenone

Q= naphthalene

Irradiation time= 13 hr. 7 min.

area P2 mole P2 -3
[Q], M area Sl mole Sl [P2], 10 M egz/ ’PZ
0.00 0.544 0.647 9.65_ -.
0.0409 0.447 0.532 7.93 1.22
0.0676 0.394 0.469 7.00 1.38
0.151 0.347 0.413 6.16 1.57.

k T = 4.81

Standard g.c. conditions; column temperature= 185°C.

115

.e: «Hm an nououwcoa .e

.0 ommH nousuouum809 sesHoo kucoauwocoo .o.m unacceum

 

 

 

88.8 n h x
88.~ m~.m 88~.8 84.8 H888.8 8888.8 88~.8
88.H 8H.m 88~.8 88.8 8888.8 H888.8 88H.8
mv.H 8~.m 88~.8 88.8 8888.8. 8888.8 HNH.8
8~.H 88.8 868.8 88.8 88H.8 H888.8 H888.8
8H.H 88.8 888.8 88.8 MHH.8 8888.8 8888.8
8H.H 8H.~ ~8H.8 88.8 ~HH.8 H888.8 88H8.8
. 88.H H8H.8 88.8 88H.8 8HH.8 88.8
. mm.~ 88H.8 88.8 8HH.8. 8888.8 88.8
~8e~m . . ~ ~ . ~ H H .
\ .8. : H..8H H H8 8 H «0 :oHumuoun< z vnoH H 88 m «Hoe m noun 2 .0.
mm «Hoe «m none
.8H8 8 .8: H uoaHu coHuaHoouuH

ounoNGobHaucomnc z ommoo.o I

undead IH

ocoHasunmn: Io

ococunQOuconou0H£01m Inn

Hm

.4 omen an ocHuoHnoouuouconuuo CH osocmsaoNsonooowam z vao.o no msficocoso

.om magma

LIST OF REFERENCES

10.
11.

12.

13.

14.

lSu

16.

LIST OF REFERENCES

P.G. Sammes in "Chemistry of the Carbon-Halogen Bond," S.
Patai, ed., Wiley, New York, N.Y., 1973, Ch. 11.

J.R. Majer and J.P.Simons, dv e , 137 (1964).

P.J. Kropp, G.S. Poindexter, N.J. Pienta, and D.C.
Hamilton. 11_Aml_gheml_§2211_2§. 8135 (1966)-

P.J. Kropp, J.R. Gibson, J.J. Snyder, and 6.8. Poindexter,
18;, Let;,, 207 (1978).

P.J. Kropp, P.R. Worsham, R.I. Davidson, and T.H. Jones,
J, Am, ghee. See,, 195, 3972 (1982).

P.J. Kropp, S.A. McNeely, and R.D. Davis, em.
§QQLL_1Q§, 5907 (1933)-

P.J. Kropp and N.J. Pienta, J, Qrg, Chem,, 48, 2084
(1983). .

S.J. Cristol, R.J. Optiz, T.H. Bindel, and W.A. Dickenson,
1, Am. Chem. Soc.. 192, 7977 (1980).

S.J. Cristol, D.P. Stull, and R.D. Daussin, 1e_Ame_Qheme
32211.129, 6674 (1978)-

P.J- Kropp. Aest§l_§heml_ae§11_ll. 131 (1984)-
S.J. Cristol and B.E. Greenwald, Ie§e_Le§§e, 2105 (1976).

S.J. Cristol and T.H. Bindel, J. grg. Qhem., 45, 951
(1980).

S.J. Cristol and T.H. Bindel, J, Am. Chem, §ee., 103, 7287
(1981).

M. Fox, W.C. Nichols Jr., and D.M. Lemal, 1e_Ame_gheme
§QC,. 9§, 8164 (1973).

J.T. Pinhey and R.D.G. Rigby, Tet. LettH 1g, 1267 (1969).

R.K. Sharma and N. Kharasch, Angew. Qhem. Intezget. Ee..
1, 36 (1968).

117

17.

18.
19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

33.
34.

35.

118

S.M. Kupchan and H.C. Wormser, J . 30, 3792
(1965).

W. Wolf and N. Kharasch, J, grg, Qhem., 39, 2493 (1965).
W. Wolf and N. Kharasch, J, grg, Qhem., 25, 283 (1961).

T. Matsuura and K- Omura. Eulll_£hem1_§esllllapanl_32. 944
(1966).

A. Nickon and B. R. Aaronoff, J, ng. Chem. , 22, 3014
(1964).

J.M. Blair, D. Bryce-Smith, and B.W. Pengrilly, ll_Qh§ml
£9911 (London), 3174 (1959).

J.M. Blair and D. Bryce-Smith, J, Qh em, § oeH (London),
1788 (1960).

J.A. Kampmeier and E. Hoffmeister, J, Am. Qhem, 599,, 84,
3787 (1962).

N. Kharasch, W. Wolf, T. J. Erpelding, P. G. Naylor, and L.-
Takes, Chem__an§_lngl 1720 (1962)

N. Kharasch, T.G. Alston, H.B. Lewis and W. Wolf, Qneme
Cemmunl, 242 (1965).

J.B. Plumb and C.E. Griffin, J. 9:9, gnem,, 27, 4711
(1962).

J.B. Plumb, R. 0brycki, and C.E. Griffin, J, Org. Chem.,
31, 2455 (1966).

R.A. Bowie and 0.C. Musgrave, g, Qnem. Sec. (London) _
566 (1966).

N. Kharasch and L. Gotlich, Angew. Chem., 74, 651 (1962);
Ange!1_ghem1_lgternatl_zgitll_1. 459 (1962)-

E.J. Baum, J.K.S. Wan, and J.N. Pitts Jr., Je_Ame_gheme
$9211.33: 2552 (1955)-

J.H. Sedon, Masters Thesis (1976), "The Photochemistry of
Some Halosubstituted Phenyl Alkyl Ketones," p. 74.

reference 32 p. 62.

reference 32 p. 66.

E.J. Baum and J.N. Pitts, e. Enye, ghee,. 70, 2066 (1966).

36.

37.

38.

39.

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

51.

52.

53.

119

P.J. Wagner, AQQEE: Qhem. Res,. 3, 168 (1971).

N-C- Yang and D--D-H- Yang. £1_Aml_§heml_§osll_fifl. 2913
(1958).

reference 32 p. 5.

a- w.n. Cohen, Chem1_fleekhladl_13. 596 (1916)-
b. w.D. Cohen. Besl_traxl_snimll_32. 243 (1920)-

a. H. -G. Heine, J. -J. Rosenkranz, and H. Rudolph, Ange__
Qhem1_lnternatl_zgitll_11 974 (1972) ,

b. W. M. Moore, G. 8. Hammond and R. P. Foss, 11.5ml_9h§m1
£221. 83, 2789 (1961).

P.J. Wagner, R.J. Truman, and J.C. Scaiano, Je_Ame_gheme
$99,. 197, 7093 (1985).

A. Streitweiser, Jr. and C.H. Heathcock, "Introduction to
Organic Chemistry," 2nd ed., Macmillan Publishing Co.,
Inc., NY, 1981, p. 1194.

P J Wagner and R G Zepp, ll_Aml_Qheml_§2211_2_. 287
(1972).

F.D. Lewis and J.G. Magyar, J, Am, Qhem, 509,. 25, 5973.
P.J. Wagner and I.E. Kochevar, J, Am, Qhem, $99,, 99, 2232
(1968).

S.L. Murov, "Handbook of Photochemistry," Marcel Dekker,
Inc., New York, 1975, p. 85.

G- Favaro, Chem1_£h2§1_Lettll_21. 401 (1973)-

J.H. O'Donell, J.T. Ayres, and C.K. Mann, e . 5,
1161 (1965).

P.J. Wagner, P.A. Kelso, and R.G. Zepp, Je_Ame_gneme_§eeeL
34, 7480 (1972).

D.D. Perrin, W.H.L. Armarego, and D.R. Perrin,
"Purification of Laboratory Chemicals," 2nd ed., Pergamon
Press, New York, p. 146.

reference 50 p. 249.

reference 50 p. 555.

R.J. Truman, Ph.D. Thesis (1984), "Photoreduction of
Phenyl Ketones by Aromatic Donors," p. 223.

54.

55.

56.

57.

58.

59.

60.

61.

62.

63.

64.

120
reference 53 p. 236.

A. Passerini, S. Giorgianni, A. Gambi, and S. Ghersetti,

§E§§1_L§§§11_1;. 729 (1980)-

"Handbook of Proton-NMR Spectra and Data," ed. Asahi
Research Center Co., Ltd. Academic Press Japan, Inc.
Tokyo, 1985, A, p. 359.

reference 56, 1, p. 391.

reference 56, 1, p. 389.

reference 56, g, p. 3.

J. Ferguson and H.J. Tinson, J. Chem, Soc., 3083 (1952).

P.J. McCarty, C.H. Tilford, and M.G. Van Campen, J. Am.
W. 472 (1957) -

S. Giorgianni, A. Passerini, A. Gambi and S. Ghersetti,
§E§Q&_L§§£LL_11I 445 (1980)-

N.S. Bhacca and D.R. Williams, "Applications of NMR
spectroscopy in Organic Chemistry: Illustrations from the
Steroid Field." Holden-Day, Inc., San Francisco, 1964,

p.2.

J.A. Barltrop and J.D. Coyle, "Principles of
Photochemistry." John Wiley and Sons, Ltd., New York, p.
110.

IIIIII

HICH

I

13112

169

N

STATE UNIV. LIBRARIES
WWWWMWWWWW
93007851631