Bis(alky-ne) complexes of the type [WI 2(CO)(NCR)(η 2-R′C 2R′) 2] (R = Et, tBu, Ph or CH 2Ph; R′ = Me or Ph). X-ray crystal structure of [WI 2(CO)(NC tBu)(η 2-MeC 2Me) 2

Abstract

Reaction of [WI 2(CO) 3(NCR) 2] (R = Et, tBu, Ph or CH 2Ph) with an excess of but-2-yne or two equivalents of PhC 2Ph in CH 2Cl 2 at room temperature gave the bis(alkyne) complexes [WI 2(CO)(NCR)(η 2-R′C 2R′) 2] (R′ = Me or Ph) ( 1– 8). The crystal structure of the tbutylnitrile complex [WI 2(CO)(NC tBu)(η 2-MeC 2Me) 2] ( 3) was determined by X-ray crystallography. The geometry about the tungsten can be considered to be octahedral, with the but-2-yne ligands, as expected, cis- and parallel to each other and trans- to the two iodo-ligands, leaving the acetonitrile and carbonyl ligands mutually trans-. The alkyne ligands in these complexes donate a total of six-electrons to the metal, as suggested by 13C NMR spectroscopy.