EPR spectra of the complexes of P(OMe) 3 and PMe 3 with Cu atoms in hydrocarbon matrices at 77 K

Abstract

The paramagnetic products from reacting Cu atoms with P(OMe) 3 and PMe 3 on a rotating cryostat have been examined by EPR spectroscopy and shown to be mainly the seventeen-electron tris(trivalent phosphorus) complexes, Cu[PX 3] 3. Their magnetic parameters are consistent with a planar π radical structure in D 3h symmetry. The Cu undergoes sp 2 hybridization with the phosphorus ligands donating their lone-pair electrons into these three empty orbitals and the unpaired electron occupying mainly the remaining Cu 4p z orbital perpendicular to the molecular plane. There is less back donation of unpaired spin population into P σ* or 3d orbitals than there is into the π* orbitals of CO in the isostructural carbonyl complex, Cu(CO) 3.