Free Radicals in Dicarboxylic Acids: An e.s.r. Study of γ-irradiated Single Crystals of Glutaric Acid at 77 K

Summary Electron spin resonance techniques were used to study the γ-radiation-induced free radicals in single crystals of glutaric acid in the temperature range from 77 K to 300 K. Three different radicals are stabilized at 77 K. The decarboxylation radical is the dominant species and the other two radicals are assigned to the anion and to the substituted acetyl σ-radical. When the temperature of the crystal is raised, these radicals disappear and the previously studied room temperature radicals appear. E.S.R.-data and the results from semi-empirical INDO-MO calculations were compared in order to elucidate the structures of the various radicals.