Efficient photochemical reduction of CO2to CO by visible light irradiation of systems containing Re(bipy)(CO)3X or Ru(bipy)32+–Co2+combinations as homogeneous catalysts

Efficient photogeneration of either (CO + H2) simultaneously, or CO selectively, occurs on visible light irradiation of CO2 solutions in (HOCH2CH2)3N–dimethylformamide containing, respectively, Ru(bipy)32+–Co2+ combinations or the single component Re(bipy)(CO)3X (X = Cl, Br) as homogeneous catalysts.