Electron resonance study of Schlenk's hydrocarbon

Abstract

Three paramagnetic species may be formed when the dichloride precursor of Schlenk's hydrocarbon is treated with zinc. We have measured and analysed their electron resonance spectra in both fluid and solid solution. Theoretical calculations of the zero-field splitting for various conformations of Schlenk's hydrocarbon suggest that this is indeed the species responsible for the solid-state spectrum. A marked deviation from planarity of the triplet state is indicated by the calculations. The two other radicals yield high-resolution electron resonance spectra in fluid solution. One of the radicals is identified as m-(diphenylmethyl)triphenylmethyl, formed from the triplet state by hydrogen-atom abstraction from the solvent. The third species is also a meta-substituted triphenylmethyl radical, although we are unable to identify the substituent.