Spectroscopic properties, structure and reactivity of [WCl(SnCl3)(CO)3(NCMe)2

Abstract

A series of seven-coordinate tungsten(II) nitrile complexes of the type [WCl(SnCl3)(CO)3(NCR)2](1–4), R=Me, Et, n-Bu, Ph, has been synthesized. These new complexes have been characterized by IR, NMR and UV-vis spectroscopy. In addition single-crystal X-ray diffraction was used to structurally characterize [WCl(SnCl3)(CO)3(NCMe)2](1). The most 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 alkyne ligands. The alkyne tungsten(II) complexes 5–8 formed were structurally characterized by IR and NMR spectroscopy. The complex 1 has been found to be an active catalyst for the polymerization of phenylacetylene. The structures and mechanisms of the formation of various new types of complexes and their role in the catalytic process are discussed.