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The 16 CB11(CH3)(n)(CD3)(12-n)(center dot) Radicals with 5-Fold Substitution Symmetry: Spin Density Distribution in CB11Me12 center dot

Kaleta, Jiri
Tarabek, Jan
Akdağ, Akın
Pohl, Radek
Michl, Josef
The syntheses of all 16 CB11(CH3)(n)(CD3)(12-n)(center dot) radicals with 5-fold substitution symmetry are described. The variation in the width of their broad and featureless electron paramagnetic resonance signals as a function of the deuteriation pattern is used to deduce the relative values of the average hyperfine coupling constants a(H) of the hydrogen atoms in the ipso (1), ortho (2-6), meta (7-11), and para (12) methyl groups, a(H)(i):a(H)(o):a(H)(m):a(H)(p) = (0.18 +/- 0.09):(0.71 +/- 0.02):(1.00 +/- 0.03):(0.52 +/- 0.05), and these can be compared with ratios expected from a B3LYP/EPRII calculation, 0.04:0.55:1:0.51.