ESR Studies on Negative Ions of Biphenyl Derivatives. I. Electron Spin Resonance Hyper fine Spectra of 4-Methyl Biphenyl and p, p′-Bitolyl Mononegative Ions

The electron spin resonances of 4-methyl biphenyl and p, p′-bitolyl mononegative ions were observed in either dimethoxyethane or tetrahydrofuran, using potassium metal as a reducing agent. Well-resolved proton hyperfine spectra were observed in each case, and the g-value, the overall width, and the hyperfine splitting coefficients due to the methyl protons and ring protons were determined. The theoretical spectra were constructed according to the spin densities calculated by Hückel’s MO treatment, and these results were compared with the observed spectra.