SPECTROSCOPIC PROPERTIES, STRUCTURE AND REACTIVITY OF [WCL(SNCL3)(CO)(3)(NCME)(2)]

A series of seven-coordinate tungsten(II) nitrile complexes of the typ e [WCl(SnCl3)(CO)(3)(NCR)(2)](1-4), R=Me, Et, n-Bu, Ph, has been synth esized. These new complexes have been characterized by IR, NMR and UV- vis spectroscopy. In addition single-crystal X-ray diffraction was use d to structurally characterize [WCl(SnCl3)(CO)(3)(NMe)(2)](1). The mos t prominent feature of complex 1 is the facility by which acetonitrile and carbonyl ligands can be replaced by other ligands. Complexes were isolated in which CO and acetonitrile ligands were substituted by alk yne ligands. The alkyne tungsten(II) complexes 5-8 formed were structu rally characterized by IR and NMR spectroscopy. The complex 1 has been found to be an active catalyst for the polymerization of phenylacetyl ene. The structures and mechanisms of the formation of various new typ es of complexes and their role in the catalytic process are discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.