Efficient visible-light-induced hydrogenation over composites of CdS and ruthenium carbonyl complexes

Hybrid systems built by coupling CdS with a series of Ru carbonyl complexes ([Ru(bpy)2(CO)2](PF6)2 (RC-1), [Ru(phen)2(CO)2](PF6)2 (RC-2), [Ru(bpy)(CO)2Cl2] (RC-3), [Ru(Me2bpy)(CO)2Cl2] (RC-4), and [Ru(phen)(CO)2Cl2] (RC-5)) showed activity for the hydrogenation of carbonyl compounds under visible-light irradiations in the presence of appropriate sacrificial agent. The influences of the irradiations mode, sacrificial agent, substrates, and the structure of the Ru complexes on the hydrogenation performance of these composites were investigated. Results indicated that CdS act as the photosensitizer, while the Ru carbonyl complexes as catalytic active component. This study provides some guidance in the development of feasible hybrid photocatalytic systems encompassing visible-light-responsive semiconductors and redox-active transition metal complexes, which are expected to find great potentials in the photocatalytic organic transformations. It is believed that such photocatalytic systems can be built in a more controllable way based on our understanding on the structure–activity relationship of the molecular electro-catalyst.