| Abstract | Dicyanomethyl and tricyanomethyl have been prepared and examined by EPR spectroscopy. Their EPR parameters at 20° are: HĊ(CN)2, g = 2.0033, aH = 19.18, aN = 2.75, a13Cα = 29.18 G; Ċ(CN)3, g = 2.0033, aN = 2.28, a13Cα = 22.06, a13Cβ = 18.20. It is concluded, on the basis of the 13Cα couplings and from the results of INDO calculations, that both radicals are planar. The 13Cα couplings, which were measured with enriched material, increase slightly with increasing temperature because the magnitude of the out-of-plane vibrations of the Cα substituents increases. Both radicals decay with second-order kinetics, the HĊ(CN)2 radical at close to the diffusion-controlled limit (k2EPR = 1.2 × 1.2 × 109 sec-1 at 20°), but Ċ(CN)3 decays considerably more slowly. |
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