Solvation spectra. Part 30.—E.s.r. spectra of substituted p-benzosemiquinone anions as a function of solvent, cation, and temperature
E.s.r. spectra of the alkali metal ion-pairs of p-benzosemiquinone, durosemiquinone, and various 2,6-disubstituted semiquinones are reported in solvents t-pentyl alcohol, D.M.E. and T.H.F. over a range of temperatures. In all cases the anions are magnetically asymmetric and ΔA, a measure of this deviation from symmetry, is discussed in terms of the structure of the ion-pairs. When possible, the relative rates of cation migration between the two oxygen atoms are considered in the light of these results, together with the magnitude of the metal hyperfine coupling constants.