CO2 cleavage by tantalum/M (M = iridium, osmium) heterobimetallic complexes

Abstract

A novel Ta/Os heterobimetallic complex, [Ta(CH₂tBu)₃(μ-H)₃OsCp*], 2, is prepared by protonolysis of Ta(CHtBu)(CH₂tBu)₃ with Cp*OsH₅. Treatment of 2 and its iridium analogue [Ta(CH₂tBu)₃(μ-H)₂IrCp*], 1, with CO₂ under mild conditions reveal the efficient cleavage of CO₂, 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)H₂ and Cp*Os(CO)H₃, respectively. This bimetallic reactivity diverges from more classical CO₂ insertion into metal–X (X = metal, hydride, alkyl) bonds.