E.S.R. studies of ion pairs formed by alkali metals with 1,2-type semiquinones

Abstract

The e.s.r. spectra of the ion pairs formed by 1,2-naphthosemiquinone and acenaphthenesemi-quinone with each of the five alkali metals have been recorded over the temperature range –80 to +20°C. No signs of linewidth alternation were found in any of the ten ion pairs. It is suggested that extremely rapid cation jumping is taking place between the two adjacent sites defined by the two oxygen atoms and that all the spectra are fast averaged. For each free radical anion the alkali metal h.f.s.c. show a simple trend with interionic separation, in that a_m/Q_m values give a smooth plot against 1/r_m. It is concluded that the h.f.s.c. for Rb and Cs in 1,2-naphthosemiquinone ion pairs are negative.