Photocatalytic Conversion of CO to CO by a Copper(II) Quaterpyridine Complex.

The invention of efficient systems for the photocatalytic reduction of CO comprising earth-abundant metal catalysts is a promising approach for the production of solar fuels. One bottleneck is to design highly selective and robust molecular complexes that are able to transform the CO gas. The Cu quaterpyridine complex [Cu(qpy)] (1) is found to be a highly efficient and selective catalyst for visible-light driven CO reduction in CH CN using [Ru(bpy) ] (bpy: bipyridine) as photosensitizer and BIH/TEOA (1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole/triethanolamine) as sacrificial reductant. The photocatalytic reaction is greatly enhanced by the presence of H O (1-4 % v/v), and a turnover number of >12 400 for CO production can be achieved with 97 % selectivity, which is among the highest of molecular 3d CO reduction catalysts. Results from Hg poisoning and dynamic light scattering experiments suggest that this photocatalyst is homogenous. To the best of our knowledge, 1 is the first example of molecular Cu-based catalyst for the photoreduction of CO .