An iridium N-heterocyclic carbene complex [IrCl(CO)2(NHC)] as a carbon monoxide-releasing molecule (CORM).

Four NHC complexes of rhodium and iridium of the general structure [RhI(COD)(NHC)], [IrCl(COD)(NHC)], [IrCl(CO) 2 (NHC)], and [Ir(N 3 )(COD)(NHC)] (NHC = N -heterocyclic carbene) were synthesised and characterised, including X-ray structure determination for all three iridium compounds. Release of carbon monoxide from [IrCl(CO) 2 (NHC)] occurred via a rapid bolus of CO on a very short timescale, independent of whether the experiment was performed in the dark or with UV-light illumination, thus establishing the compound as a novel ligand-exchange triggered CO-releasing molecule (CORM). The azide complex represents the first iridium–NHC complex containing an azide ligand. [ABSTRACT FROM AUTHOR]