Electron addition to triphenylmethyl arsonium iodide. An electron spin resonance study

Abstract

Exposure of crystalline Ph3AsMe+I– crystals to 60Co γ-rays at 77 K yields an electron-adduct having e.s.r. parameters characteristic of methyl radicals weakly interacting with a Ph3As molecule. We now find that, on annealing, this species dissociates to give normal methyl radicals, whilst solutions in methanol (CD3OD) give, on electron addition at 77 K, the normal arsoranyl radical [Ph3AsMe] together with methyl radicals, there being no trace of the adduct formed in the crystalline material. Reasons for these differences are discussed and it is suggested that the arsoranyl radical rearranges to a σ* species as a necessary step in the dissociation process.