Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 94. Synthesis of di- and tri-metal compounds via the reagents [M(C–CCBut)(CO)2(η-C5H5)](M = Mo or W)

The alkynylmethylidynemetal compounds [M(C–CCBut)(CO)2(η-C5H5)](M = Mo or W) react with [Fe2(CO)9] in thf (tetrahydrofuran) at ambient temperatures to afford via alkylidyne group coupling the trimetal complexes [M2Fe{µ3-C2(CCBut)2}(CO)7(η-C5H5)2] in good yield. The reaction between the alkynylmethylidynetungsten reagent and [Fe2(CO)9] also gives small quantities of [Fe2{µ-ButC2CW(CO)2(η-C5H5)}(CO)6], a product in which a Fe2(CO)6 fragment is attached to the terminal CCBut group of the [W(C–CCBut)(CO)2(η-C5H5)] molecule. Treatment of [Mo(C–CCBut)(CO)2(η-C5H5)] in light petroleum with [Rh(CO)2(η5-C9H7)](C9H7= indenyl) affords a chromatographically separable mixture of the compounds [MoRh(µ-C–CCBut)(CO)3(η-C5H5)(η5-C9H7)], [Mo2Rh{µ3-C2(CCBut)2}(CO)4(η-C5H5)2(η5-C9H7)], and [MoRh2{µ3-C–CC-But}(µ-CO)(CO)2(η-C5H5)(η5-C9H7)2]. The corresponding tungsten–rhodium species [WRh(µ-C–CCBut)(CO)3(η-C5H5)(η5-C9H7)], and [WRh2{µ3-C–CCBut}(µ-CO)(CO)2(η-C5H5)(η5-C9H7)2] have also been prepared. The dimetal compound [MoRh(µ-C–CCBut)(CO)3(η-C5H5)(η5-C9H7)] reacts with [W(C–CCBut)(CO)2(η-C5H5)] to give the trimetal complex [MoWRh{µ3-C2(CCBut)2}(CO)4(η-C5H5)2(η5-C9H7)], while [WRh(µ-C–CCBut)(CO)3(η-C5H5)(η5-C9H7)] with [Fe2(CO)9] and [Co(η-C2H4)2(η-C5Me5)] affords, respectively, the compounds [WFeRh(µ3-C–CCBut)(µ-CO)(CO)5(η-C5H5)(η5-C9H7)] and [WCoRh(µ3-C–CCBut)(µ-CO)(CO)2(η-C5H5)(η-C5Me5)(η5-C9H7)]. The 1H and 13C-{1H} n.m.r. data for the new compounds are reported and discussed.