Synthesis, crystal structure, and reactivity of the (η4-1,3-diphosphacyclobutadiene)(η5-1,2-dicarbaborane)rhodium complex [NEt4][Rh(η4-P2C2But2)(η5-C2B9H11)]

Tetrahydrofuran solutions of K[Rh(PPh3)2(η5-C2B9H11)] react with ButCP and NEt4Cl to afford the salt [NEt4][Rh(η4-But2 C2P2)(η5-C2B9H11)], which with [AuCl(PPh3)] and [Co(CO)2(NCMe)(η4-C4Me4)][PF6] yields the compounds [Rh(η4-But2C2P2MLn)(η5-C2B9H11)][MLn= Au(PPh3) or Co(CO)2(η4-C4Me4)]; all structurally identified by X-ray diffraction.