文摘
The addition of methyl acetamidomethyl groups at the 4,4鈥?positions of a 2,2鈥?bipyridyl ligand is found to enhance the rate of a bimolecular reduction mechanism of CO2 by ReI fac-tricarbonyl chloride complexes. Electrochemical studies, spectroelectrochemical measurements, and molecular dynamics simulations indicate that these methyl acetamidomethyl groups promote the formation of a hydrogen-bonded dimer. This supramolecular complex catalyzes the reductive disproportionation of CO2 to CO and CO32鈥?/sup> at a lower overpotential (ca. 250 mV) than the corresponding single-site 2 e鈥?/sup> reduction of CO2 to CO and H2O catalyzed by the corresponding model complex with a 4,4鈥?dimethyl-2,2鈥?bipyridyl ligand. These findings demonstrate that noncovalent self-assembly can modulate the catalytic properties of metal complexes by favoring alternate catalytic pathways.