A New Approach to the Reduction of Carbon Dioxide: CO₂ Reduction to Formate by Transfer Hydrogenation in iPrOH

A series of four Ir and Ru catalysts have been tested in the reduction of CO 2 to formate in the presence of H 2 . The iridium catalysts containing the basic NHC ligands were the ones to show better catalytic activities, achieving high TON values of up to 1800 TON. The unprecedented reduction of CO 2 with i PrOH through a hydrogen transfer process is also described. TON values of up to 150 were obtained. Two other secondary alcohols, cyclohexanol and 1-phenylethanol, were also used as hydrogen sources for the reduction of carbon dioxide.