Chemistry Reference
In-Depth Information
TABLE 9.5. ZFS Parameters of the Quartet Species
p-
6 in Argon Matrix (
g
iso
¼2.003)
Fluorine Distribution
jD
/hc
j
(cm
1
)
jE
/hc
j
(cm
1
)
2,3,5,6-(
b
)
0.285
0.043
2,6-(
c
)
0.291
0.040
2,3,6-(
d
)
0.289
0.041
2,3,5-(
e
)
0.283
0.042
2,5-(
f
)
0.278
0.040
2,3-(
g
)
0.287
0.040
2-(
h
)
0.285
0.040
3,5-(
i
)
-
-
TABLE 9.6. Analysis of the Calculated D-Tensor (B3LYP/TZVPP) of Quartet
p
-6b
D
E
Total (calculated)
0.261
0.017
Experiment
0.285
0.043
Spin-spin
0.226
0.024
Spin-orbit
0.035
0.007
Spin-spin
1-Center
0.273
0.034
2-Center
0.049
0.010
3-Center
0.002
0.000
4-Center
0.000
0.000
0.018
Coulomb
0.182
Exchange
0.044
0.042
Spin-orbit
M
¼
0(
a
!
a
)
0.002
0.006
M
¼
0(
b!b
)
0.001
0.006
M¼þ
1(
b!
a
)
0.001
0.003
M¼
1(
a
!b
)
0.040
0.003
All values are in cm
1
.
9.5.2 Phenyl Nitrene-2-yl
After subsequent irradiation of the phenyl nitrene
o-
, several very weak signals at
1670, 1890, 5910, 6280, and 7300 G can be identified (Fig. 9.14). These signals
disappear upon annealing of the matrix at 30 K. A similar behavior was also observed
for
p-
5b
11,13
and is characteristic of radical pairs. In accordance with the results from
the simulation of the EPR spectrum, the weak EPR signals are assigned to nitreno
radical
o-
6b
due to the orbital degeneracy and
strong spin-spin coupling in the iodine atoms, no signals in the EPR spectra can be
assigned to iodine atoms in the matrix produced by the C
6b
in its quartet ground state. As for
p
-
6b
I bond cleavage.
The experimental EPR spectrum of
o-
6b
could be simulated assuming a quartet
0.357 cm
1
0.0136 cm
1
state with the ZFS parameters
j
D
/hc
j¼
and
j
E
/hc
j¼
