THE ELECTRON SPIN RESONANCE ABSORPTION SPECTRA OF SEMIQUINONE IONS: PART I. THE HYPERFINE SPLITTING DUE TO ALKOXY GROUPS

The electron spin resonance absorption spectra of semiquinone ions with alkoxy groups have been examined and compared with those with substituted alkyl groups. The splitting constant for the alkoxy protons has been found to be about one-half that of alkyl protons in the corresponding free radical. Hyperfine splittings due to methoxy, ethoxy, and isopropoxy protons have been demonstrated using the semiquinone ions formed by oxidation of alkyl gallates. The available evidence suggests that, in accounting for the hyperfine splitting due to alkyl protons, spin polarization is as important as electron delocalization.