Indo study of the angular dependences of isotropic hyperfese interaction constants in the model conformations of the nitrobenzene radical anion

The UHF/INDO calculations of the model conformations of the nitrobenzene radical onion show that rotation of the nitro group relative to the plane of the benzene ring is accompanied by a pyramidal distortion of the group caused by the pseudo-Jahn-Teller effect (vibronic interaction between the ground n and totally symmetric lowest excited σ states). The angular dependences of the¹⁴N,¹³C,¹H, and¹⁷O Isotropic hyperfine interaction constants are analyzed. Experimental ESR data are interpreted for the radical anions of nitrobenzene derivatives with ortho-alkyl groups. Translated fromZhumal Strukturnoi Khimii, Vol. 41, No. 3, pp. 457-467, May-June, 2000.