ENDOR spectra of some semiquinone radical-anions

Abstract

The proton ENDOR spectra of the radical-anions of several semiquinones in alkaline ethanol solution are reported. p-Benzosemiquinone and 2,5-dimethyl-p-benzosemiquinone are converted to di-alkoxy substituted derivatives through reaction with the solvent. When this happens the e.s.r. spectra become complicated because the spectra of the primary and secondary radicals overlap: the power of ENDOR for analyzing overlapping e.s.r. spectra is illustrated.