E. s. r. and ionic association. Formation of ion pairs and triple ions of 9,10-anthrasemiquinone

Abstract

Electron spin resonance spectra of 9,10-anthrasemiquinone as the free ion, ion-pair and triple ion (counter ion, Na+) in tetrahydrofuran, and as the triple ion in 2-methyltetrahydrofuran are presented and discussed in terms of the structures of the ionic associates. The ion-pair is “locked-in” to an asymmetric configuration at –65°C, but at 20°C intramolecular transfer of the cation between the oxygen of the anion is observed. The triple ion is symmetrical, one sodium associating with each oxygen, and occupying a position close to the O—O axis.