Electron spin resonance study of o-benzosemiquinone alkali metal ion pairs

Abstract

The e.s.r. spectra of o-benzosemiquinone alkali metal ion pairs have been recorded over a large range of temperature and for several solvents. The hyperfine coupling constants of the metal nuclei and their variation with temperature are discussed in relation to theoretical calculations performed for different models of the ion pairs. ¹³C splittings are measured for carbon nuclei occurring in the three different positions in the molecule in natural isotopic abundance and their assignment is discussed. Spectra due to other radical species are observed and are attributed to substituted quinones.