Radical cations of 1,2,4,5-tetrakis(dimethylamino)benzene and 2,3,6,7-tetrakis(dimethylamino)naphthalene: an ESR and ENDOR study

The title radical cations, 2.+ and 3.+, were generated by oxidation of the parent compounds with tris(4-bromophenyl)aminium hexachloroantimonate, iodine or lead tetraacetate, and were characterized by ESR and ENDOR. For 2.+ a restricted rotation about the C(aryl)N bond is found at low temperature (≤ 230 K). The remarkably low a(HCH3)/a(N) ratios of 2.+ and 3.+ point to an increase in the average degree of bending at nitrogen