Chemistry Reference
In-Depth Information
O
O
O
O
H
h
ν
N
3
N
Ar
Ar
H
Ar
Ar
Ar
O
37 53 54 55
Product ratio
a: Ar = Ph
b: Ar =
p
-ClPh
c: Ar =
p
-BrPh
d: Ar =
90
100
90
71
76
77
7
3
10
12
24
16
-CN
e: *
f: Ar =
p
-Ph-
p
-Ph
p
3
7
O
N
3
*
O
O
SCHEME 5.21.
studies support the notion that triplet alkyl nitrenes are long-lived intermediates that
scavenge for benzoyl radicals.
87
Product formation from
is not affected by the electron configuration of the T
1K
in the acetophenone sensitizer,
63
although
37
a
-cleavages are generally thought to arise
p
) configuration. However, triplet energy transfer can
from the triplet ketone with (
n
,
O
N
3
Ar
37
-Cleavage
- CH
2
N
3
α
β
-cleavage
.
Energy
transfer
O
O
O
O
h
ν
.
N:
N
Ar
Ar
Ar
Ar
Ar
.
N
Benzoyl radical
O
Acetophenone radical
Nitrene
38
O
O
O
Ar
Ar
Ar
N
Ar
H
O
55
53
54
SCHEME 5.22.
