Radicals derived from 1,4-disubstituted anthraquinones. Further evidence for association of quinones in solution

Abstract

The radicals derived from three 1,4-disubstituted anthraquinones containing NH₂, NHMe and OH substituent groups have been studied in methanol solution using the technique of pulse radiolysis. Absorption spectra and rates of formation of semiquinone radical species (DH· and D^–_.), formed respectively under acidic and alkaline conditions, have been recorded. Aggregation of the ground state dye must be assumed to obtain positive extinction coefficients for the radical formed under alkaline conditions.