Radical cations of nitroso derivatives. A radiation-chemical and electron spin resonance study

Abstract

Exposure of dilute solutions containing nitrosobenzene in trichlorofluoromethane to ⁶⁰Co γ-rays at 77 K gave the corresponding radical cation, characterised by e.s.r. spectroscopy. The results confirm the interpretation of liquid-phase data assigned to this cation, which showed that loss is from an in-plane σ-orbital localised on nitrogen and oxygen, rather than from the aromatic π-system. However, solutions containing the t-butyl derivative in equilibrium with its dimer,(Me₃CNO)₂, gave primarily the dimer cation, (Me₃CNO)⁺₂, with possible traces of the monomer cation. The e.s.r. data for the latter resemble those for the nitrosobenzene cation, whereas results for the dimer cation suggest that loss is from a π-type orbital with very low spin density on the two equivalent nitrogen atoms.