Carbaborane dimetal complexes of molybdenum and tungsten: insertion of a bridging alkylidyne ligand into a boron–hydrogen bond

The salt [N(PPh3)2][W(CR)(CO)2(η-1,2-C2B9H9Me2)](R = C6H4Me-4) reacts with the compounds [M(CO)2(NCMe)2(η-C9H7)][BF4](M = Mo or W, η-C9H7= indenyl) to afford dimetal complexes [MW(µ-CR)(CO)3-(η-C9H7)(η-C2B9H8Me2)]; treatment of the molybdenum–tungsten species with hex-3-yne affords [MoW{µ-σ,η3-CH(R)(C2B9H8Me2)}(CO)3(η-EtC2Et)(η-C9H7)], structurally identified, as was its precursor, by X-ray diffraction.