CO 2 cleavage by tantalum/M (M = iridium, osmium) heterobimetallic complexes

A novel Ta/Os heterobimetallic complex, [Ta(CH Bu) (μ-H) OsCp*], 2, is prepared by protonolysis of Ta(CH Bu)(CH Bu) with Cp*OsH . Treatment of 2 and its iridium analogue [Ta(CH Bu) (μ-H) IrCp*], 1, with CO under mild conditions reveal the efficient cleavage of CO , driven by the formation of a tantalum oxo species in conjunction with CO transfer to the osmium or iridium fragments, to form Cp*Ir(CO)H and Cp*Os(CO)H , respectively. This bimetallic reactivity diverges from more classical CO insertion into metal-X (X = metal, hydride, alkyl) bonds.