Organic and biological spectrochemical studies. XXIV. Electron spin resonance studies on the hydroquinone cation radical

The electron spin resonance spectrum of hydroquinone in aluminium chloride – nitromethane is interpreted in terms of cis–trans isomerism. Calculations based on the variation of the spectrum with temperature lead to a value for the potential barrier to rotation about the C—O bond of ca. 10 kcal/mole. The value of the constant QOH is discussed.