Electron addition to triethylphosphite induced by ionising radiation: an ESR study

With a view to obtain [0P(OEt)3]- radical anions and to establish their preferred structure, solutions of triethylphosphite in different solvents have been exposed to 60Co γ-rays at 77K and studied by ESR spectroscopy. Two phosphorus centred radicals suggested are parent radical anion and P(OEt)2 formed by dissociative electron capture. In methyltetrahydrofuran an electron adduct with A = 264G and small value of A is assigned to the primary radical anion having a planar T structure with SOMO on 3p of phosphorus, normal to the radical plane. In a methanolic solution, the same radical anion with extensive protonation having a phosphoranyl type radical with large 1H and 31P hyperfine splitting is formed. The well defined triplets due to 2H adduct, obtained in CD3OD glasses, confirm this assignment. Other phosphorus centred radicals detected are MeO-P(OEt)3 and the cation dimer (EtO)3P-P(OEt)3+. (author). 10 refs., 2 figs., 1 tab