Reversible combination of carbon monoxide with a synthetic oxygen carrier complex.

Chlorocarbonyl-bis(triphenylphosphine)iridium(I), in solution, reacts reversibly with carbon monoxide under normal conditions, one molecule per metal atom. Formation of a 1 : 1 metal complex-CO adduct is verified by CO absorption measurements and the infrared spectrum of the adduct measured in situ. The spectrum suggests that the metal-C-O bonding is of the type found in conventional metal carbonyl.