Synthesis and crystal structure of a lanthanum complex with a diphenylphosphide ligand

Abstract

Reaction of a solution of [LaL₃(Ph₃PO)][L = N(SiMe₃)₂] with Ph₂PH followed by Ph₃PO yields [LaL₂(PPh₂)(Ph₃PO)₂], which has been isolated as highly air-sensitive orange crystals and characterised by solution NMR spectroscopy (³¹P and ¹H) and X-ray crystallography. The structure was refined to a final R value of 0.056 and shows the complex to have a terminal PPh₂^– ligand with planar co-ordination at P. Variable-temperature ³¹P NMR spectroscopy indicates rapid exchange between free and co-ordinated Ph₃PO at room temperature but at 193 K is consistent with the solid-state structure with two Ph₃PO ligands.