The carbaborane group η5-C2B9H9Me2 as a spectator and non-spectator ligand in di- and tri-metal complex chemistry: X-ray crystal structures of [PPh4][Co2W(µ3-CPh)(CO)8(η5-C2B9H9Me2)].1/2CH2Cl2, [NEt4][FeW(µ-CC6H3Me2-2,6)(CO)5-(η5-C2B9H9Me2)], and [IrW(µ-CC6H4Me-4)(CO)2(PEt3)2(η5-C2B9H9Me2)]

Salts containing the anions [W(CR)(CO)2(η5-C2B9H9Me2)]–(R = Ph, C6H4Me-2, C6H4Me-4, or C6H3Me2-2,6) react with [Co2(CO)8], [Fe3(CO)12], or [IrL2(η4-C8H12)][PF6](L = PPh3, L2Ph2PCH2CH2PPh2 or bipyridyl) to yield heteronuclear di- and tri-metal compounds in which the carbaborane ligand adopts a variety of bonding modes.