Synthesis of new CO2-soluble ruthenium(II) and cobalt(II) polypyridine complexes bearing fluorinated alkyl chains and their application to photoreduction of liq. CO2

Eight types of new CO2-soluble or CO2-philic ruthenium(II) and cobalt(II) polypyridine complexes, namely, [M(F84OPh)3](BArF)2, [M(F44OPh)3](BArF)2, [M(F62Ph)3](BArF)2, and [M(F62O)3](BArF)2 (M = Ru or Co, BArF: tetrakis[3,5-bis(trifluoromethyl)phenyl]borate), were prepared from bipyridine derivatives bearing highly fluorinated alkyl chains and applied to the photoreduction of liq. CO2 under a high pressure of 6.8 MPa at 35 °C. All these complexes have higher philicity toward liq. CO2 than the corresponding complexes with PF6− as the counteranion. Using the Ru(II)–Co(II) systems of [M(F44OPh)3](BArF)2 and [M(F62O)3](BArF)2, direct photoreduction of CO2 was achieved without the use of any organic solvent.