Diiridium Bimetallic Complexes Function as a Redox Switch To Directly Split Carbonate into Carbon Monoxide and Oxygen

A pair of diiridium bimetallic complexes exhibit a special type of oxidation reduction reaction that could directly split carbonate into carbon monoxide and molecular oxygen-via a low-energy pathway needing no sacrificial reagent. One of the bimetallic complexes, Ir-III(mu-Cl)(2)Ir-III, can catch carbonato group from carbonate and reduce it to CO. The second complex, the rare bimetallic complex Ir-IV(mu-oxo)(2)Ir-IV, can react with chlorine to release O-2 by the oxidation of oxygen ions with synergistic oxidative effect of iridium ions and chlorine atoms. The activation energy needed for the key reaction is quite low (similar to 20 kJ/mol), which is far less than the dissociation energy of the C=O bond in CO2 (similar to 750 kJ/mol). These diiridium bimetallic complexes could be applied as a redox switch to split carbonate or combined with well-known processes in the chemical industry to build up a catalytic system to directly split CO2 into CO and O-2.