Sensitized and Self‐Sensitized Photocatalytic Carbon Dioxide Reduction Under Visible Light with Ruthenium Catalysts Shows Enhancements with More Conjugated Pincer Ligands

Abstract A new method to synthesize complexes of the type [(CNC)Ru II (NN)L] n+ has been introduced, where CNC is a tridentate pincer composed two (benz)imidazole derived NHC rings and pyridyl ring, NN bidentate aromatic diimine ligand, L=bromide or acetonitrile, n=1 2. Following this series six synthesized characterized by spectroscopic, analytic, crystallographic, computational methods. Their electrochemical properties have studied via cyclic voltammetry under both N 2 CO atmospheres. Photocatalytic reduction was performed using these in presence (sensitized) absence (self‐sensitized) an external photosensitizer. This study evaluates effect different CNC, NN, L ligands sensitized self‐sensitized photocatalysis. Catalysts bearing benzimidazole show much better activity for photocatalysis as compared catalysts imidazole pincer. Furthermore, requires ligand with catalyst ACN being most active TON=85 TOF=22 h −1 electron donating 4,4′‐dimethyl‐2,2′‐bipyridyl (dmb)