Synthesis and Structure of Some New Organophosphorus Ligands and Their Metal Complexes

Following a brief introduction into the coordination chemistry of phosphorus ylides, some new examples of complexes with catalytically active metals are presented. Mononuclear derivatives of platinum, iridium, palladium, rhodium, and nickel were synthesized from salt-free (or lithiated ylides) and the metal halides and their phosphane or olefine adducts. Both ionic and non-ionic species could be isolated and characterized by analytical and spectroscopic techniques. Titanium forms predominantly binuclear compounds. Novel coordination compounds of the alkaline metals were obtained with phosphanoalkyl benzylidene phosphoranes. In a crystal structure analysis a discrete phosphanesodium donor interaction and a polyhapto coordination of the metal to the benzylidene function were detected. Mixed complexes of phosphonium-bis-methylide and bis-phosphano-methanide ligands were also investigated by x-ray diffraction in order to elucidate the structure of the latter system. The ligand was found to form a planar four-membered chelate ring with a symmetrical P-C-P moiety, characterized by strong ylidic π-bonding.