Solvation spectra. Part 19.—Electron spin resonance spectrum of monoprotonated 2,6-dimethylbenzosemiquinone and its solvent dependence

Abstract

The proton hyperfine splitting constants for monoprotonated 2,6-dimethylbenzosemiquinone prepared by photolysis are reported for solutions of this radical in several solvents. The results show that protonation occurs at the oxygen remote from the methyl groups. Previous assignments proposed for monoprotonated p-benzosemiquinone and durosemiquinone are confirmed. A correlation with the Z-value of the solvent is described.