7-COORDINATE THIOPHENE-3-ACETONITRILE COMPLEXES OF TUNGSTEN(II) - CRYSTAL-STRUCTURES OF [WI2(CO)(3)(NCCH2(3-C4H3S))(2)] AND[WI2(CO)(3)(NCCH2(3-C4H3S))(ASPH3)]

Reaction of [WI2(CO)(3)(NCMe)(2)] with 2 equivalents of thiophene-3-ac etonitrile {NCCH2(3-C4H3S)} gave the crystallographically characterise d complex [WI2(CO)(3){NCCH2(3-C4H3S)}(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 [WI2(CO)(3)(NCMe)(2)] with an equimolar amount of L {L = AsPh3 (2) or PPh3 (3)} followed an in si tu reaction with by one equivalent of thiophene-3-acetonitrile afforde d the mixed ligand complexes [WI2(CO)(3){NCCH2(3-C4H3S)}L] {2 (crystal lographically characterised) and 3}. The structure of 2 also has a cap ped octahedral geometry, again having a carbonyl ligand in the unique capping position. (C) 1998 Elsevier Science S.A. All rights reserved.