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

Abstract

With a view to obtain [°P(OEt)₃]^- radical anions and to establish their preferred structure, solutions of triethylphosphite in different solvents have been exposed to ⁶⁰CO <img src='/image/spc_char/gamma2.gif' border=0>-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 3<i>p </i> 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 are MeO-P(OEt)₃and the cation dimer (E<i>t</i>O)₃P—P(OEt)<img src='http://www.niscair.res.in/jinfo/plusthree.gif' border=0>.