Tuning Photoredox Catalysis of Ruthenium with Palladium: Synthesis of Heterobimetallic Ru–Pd Complexes That Enable Efficient Photochemical Reduction of CO2

New Ru–Pd heterobimetallic complexes were synthesized and structurally characterized utilizing 6,6″-bis(phosphino)-2,2′:6′,2″-terpyridine as a scaffold for the metal–metal bond. The dicationic Ru–Pd complex was found to exhibit high catalytic activity as a photocatalyst for photochemical reduction of CO2 to CO under visible light irradiation. This study established a new design of transition metal catalysts that tune photoredox catalysis with metalloligands.