Synthetic and spectroscopic studies of phosphoranides [PR(CN)2X]– and the crystal and molecular structure of [NEt4][PPh(CN)2Cl]

Abstract

Several new phosphoranides of the type [NR₄][PR′(CN)₂X](R′= Me, Et, Ph, or C₆F₅; X = Cl, Br, I, or NCS) have been synthesised, and characterised by means of ³¹P n.m.r. spectroscopy, elemental analysis, and (in some cases) i.r. spectroscopy. These are the first simple phosphoranides to be prepared with an organo group bound directly to phosphorus. Determination of the crystal structure of [Net₄][PPh(CN)₂Cl] has shown a monomeric distorted ψ-trigonal bipyramidal geometry for the anion, with the phenyl group equatorial and one very long P–Cl axial bond, as observed previously in the [PCl₄]^– ion. Halide ions did not form phosphoranides with PBu^t(CN)₂, PMe₂(CN), or PPh₂(CN).