Seven-coordinate thiophene-3-acetonitrile complexes of tungsten(II). Crystal structures of [WI 2(CO) 3{NCCH 2(3-C 4H 3S)} 2] and [WI 2(CO) 3{NCCH 2(3-C 4H 3S)}(AsPh 3)

Abstract

Reaction of [WI 2(CO) 3(NCMe) 2] with 2 equivalents of thiophene-3-acetonitrile {NCCH 2(3-C 4H 3S)} gave the crystallographically characterised complex [WI 2(CO) 3{NCCH 2(3-C 4H 3S)} 2] ( 1). The structure of 1 can be described as a distorted capped octahedron with a carbonyl group in the capping position, two carbonyl groups and an iodide in the capped face and two acetonitrile ligands and an iodide in the uncapped face. Treatment of the seven-coordinate complex [WI 2(CO) 3(NCMe) 2] with an equimolar amount of L {L=AsPh 3 ( 2) or PPh 3 ( 3)} followed an in situ reaction with by one equivalent of thiophene-3-acetonitrile afforded the mixed ligand complexes [WI 2(CO) 3{NCCH 2(3-C 4H 3S)}L] { 2 (crystallographically characterised) and 3}. The structure of 2 also has a capped octahedral geometry, again having a carbonyl ligand in the unique capping position.