Additions and Corrections
1252 The Journal of Physical Chemistry, Vol. 97, No. 6, 1993
ADDITIONS AND CORRECTIONS
1992, Volume 96
Kazumi Toriyma’ and MIsrrhP~Okazaki : Selectively Weakened C-C u - h n d in Cation Radicals of Linear and Branched Pentanes As Studied by Electron Spin Resonance. These corrections, however, do not affect any conclusions or discussion. On the contrary, hfc’s closer to the experimental result are obtained without assuming the additional bond angle deformation.
Page 6986. Due to an error in the atomic coordinate for the out-of-planeproton attached to the branched methyl group, the INDO values in Table I1 and those in Figures 4 and 6 are incorrect. They should be corrected as follows.
TABLE II: Observed and Calculated Hyperfine Coupling Conotants for 3-Metbylpeat.w and 3,fDimethylpent.w Cation RidiCP18’ hf coupling/mT geometry
observed
(sym)
H2,Hs,H6,H7
H2
Hs
H.5
CsFisb
TT (C,)
4.50 (2 H) 4.60 (3 H) 4.50 (3 H) 5.25,4.99, 3.93c
7.64
4.72 5.14
3.99 3.70
F113
TG TG TT (C,) TG
3.55 (3 H) 3.65 (4 H) 3.75 (4 H)
6.24
4.62 4.82
3.27 3.46
matrix
calculated
spin density on carbon H7
Ci
C2
C3
C4
Cs
c 6
0.115 0.OOO
0.114 0.082
0.236 0.245
0.297 0.276
0.030 0.027
4.009 4.009
0.100
0.112 0.054
0.229 0.233
0.310 0.301
0.016
4.009 4.015
Cl
3MP .. . .
3,3-DMP CsFis* F113
3.27 3.47
0.005
0.007
4.009 0.002
In this calculation the standard geometrical parameters, R ( C 4 ) = 0.154 nm, R(C-H) = 0.1 102 nm, and 0 = tetrahedral angle, were assumed except for the following: the C 3 4 4 bond was elongated by 0.006 or 0.01 nm and the neighboring bonds were shortened by 0.004 nm. b Almost the same spectrum was also observed in C5F12 and C6F14. From ref 11. @
a)
3.99 (4.50)
n
1.06
3.27
(3.55 : 3HI
1
b)
3.70 (3.93)
.17
3.46
%/
b)
unit: mT 1.08
( ) : obs.
( ) : obs.
F I p n 4 . Hfc’sandspindistributionsobtainedby INDO-MOcalculation for 3MP cation radicals with fully extended structure (TTform) (a) and for that with TG conformation (b). For both of them the C 3 4 4 bond was elongated by 0.01 nm. In the case of TT conformer, both the bonds C 2 4 3 and C 4 4 5 were shortened by 0.004 nm.
Figure 6. Hfc’s estimated by the INDO-MO calculation for 3,3-DMP cation radical with fully extended structure (a) and for that with TG conformation (b). In this calculation, the C 3 4 4 bond was elongated by 0.006 nm. On the other hand, other C-Cbonds except for ( 2 1 4 2 were shortened by 0.004 nm.
