A Dinculear Rhenium Complex with a Proton Responsive Ligand in the Electrochemical-Driven CO2-Reduction Catalysis

Abstract

Herein, we present a detailed study on a dinuclear Re complex bearing an α‐diimine‐tricarbonyl motif and a proton responsive ligand in the electrochemical CO2 reduction catalysis. The complex exhibits a pyrazole‐pyridine entity as α‐diimine unit and a phenol moiety as internal proton relay, which show non‐innocent behaviour under reductive conditions. Initial two electron reduction leads to NH bond cleavage forming the deprotonated ligand LH−2. Further two electron reduction at considerable negative potential induces OH bond cleavage and ligand reduction. In the presence of CO2, the reduced species reacts with CO2 forming CO. The complex shows a moderate Faraday efficiency and the activity is similar to the mononuclear derivative [Re(bpy)(CO)3(py)]+ (py=pyridine, bpy=2,2′‐bipyridine).