Synthesis of unsaturated methyl(alkylidyne)ditungsten complexes, [W2(μ-CR)(Me)(CO)3(η-C5H5)2] (R = C6H4Me-4 or C6H4OMe-2); Crystal structure of the compound with R = C6H4OMe-2

Abstract In light petroleum at reflux temperatures, the compounds [W(Me)(η-C 2 H 4 )(CO) 2 (η-C 5 H 5 )] and [W(CR)(CO) 2 (η-C 5 H 5 )] (R = C 6 H 4 Me-4 or C 6 H 4 OMe-2) afford the ditungsten complexes [W 2 (μ-CR)(Me)(CO) 3 (η-C 5 H 5 ) 2 ]. The structure of the product with R = C 6 H 4 OMe-2 has been established by X-ray diffraction. The WW bond (2.761(1) A) is spanned symmetrically by the CC 6 H 4 OMe-2 group (μ-CW, 2.01(1) A). One tungsten atom carries a cyclopentadienyl ligand and two carbonyl groups, one of which weakly semi-bridges the metal—metal bond (WCO, 168.3(9)°). The other tungsten atom is ligated by a cyclopentadienyl ring, and by a carbonyl and a methyl group (WCH 3 , 2.24(2) A).