Proximal Functionalization of Rhenium(I) Bipyridine Tricarbonyl Complexes for Photocatalytic CO2 Reduction and Carboxylation

Abstract

Two 6,6’-functionalized rhenium(I) bipyridine tricarbonyl complexes bearing hydroxy or imidazolium groups were designed and synthesized to place functional groups closer to the metal center than in the 5,5’-functionalized analogues. Single-crystal X-ray diffraction analysis confirmed the structures of these new complexes, and spectroscopic and electrochemical studies revealed the similar properties to their 5,5’-functionalized analogues. The 6,6’-functionalized complexes exhibited higher photocatalytic activity for carbon dioxide (CO2) reduction, whereas the carboxylation with CO2 was unaffected, highlighting the reaction-dependent impact of ligand functionalization.