G. W. Eastland and M. C. R. Symons
1502
Electron Spin Resonance Studies of Superoxide Ions Produced by Radiolysis in Alcoholic Media George W. Eastland+ and Martyn C. R. Symons' Department of Chemistry, The University, Leicester, LE 1 7RH, England (Received April 79, 1976; Revised Manuscript Received May3, 7977)
Air or oxygen saturated alcohols or aqueous alcohols gave 0; on exposure to @Coy rays at 77 K. These radicals were characterised by low-field parallel ESR features whose g values were solvent dependent. The shift of gl from 2.0023 was least for aqueous methanol and greatest for cyclohexanol. In some cases slight annealing ahove 77 K gave an increase in yield and a small shift in 41 toward 2.0023. Dissolution of NaO2 in these solvents gave well-defined spectra of Oz- with gll values identical with the limiting values obtained by radiolysis. On annealing the irradiated glasses the 41 features for Of decayed simultaneously with the growth of features assigned to H02. (or DOz.). In some cases ROz. radicals were also detected. Since the magnitude of 41 is controlled by the strength and direction of the hydrogen bonds, and since the parent dioxygen molecules are not hydrogen bonded, we conclude that solvation is almost completely developed at 77 K in these media within
