Electron Acceptors. Part IV : Electron Spin Resonance Spectral Studies of 2,3-Dicyano-1, 4-Naphthosemiquinone Radical

Air Force Cambridge Research Laboratories, Bedford, Mass. 01730, U.S.A.

Manuscript received 17 April 1974; accepted 10 April 1975

The radical anion of electron acceptor 2,3-dicyano-1,4-naphthoquinone (1) was conveniently generated by the action of sodium metal in THF and also by the electrolytic reduction in a MeCN-­DME mixture. Analysis of the ESR spectra suggests the presence of four equivalent protons (a_H = 0.19 G.) and two equivalent nitrogen atoms (a_N = 0.87 G.). The theoretical values of the unpaired electron spin densities and the hyperfine coupling constants for the radical anion (1) were obtained by the applications of both HMO- and INDO methods and the results were corre­lated with the experimental values.