Tridentate bis(2-pyridylmethyl)amine iron catalyst for electrocatalytic proton reduction

Abstract

For widespread applicability, successful complexes for catalytic hydrogen generation should be inexpensive and easy to synthesize. To this end, a series of tetradentate Fe(III) polypyridyl monophenolate complexes was recently reported that are stable and active electrocatalysts for reducing protons into hydrogen gas. While these complexes were active for hydrogen generation, the ligands were synthesized in moderate to good yield after multiple synthetic steps. Herein we report a tridentate iron dipyridyl amine analogue for hydrogen generation that is synthesized in a single synthetic step from commercially available materials. The resulting complex is an active electrocatalyst operating at −0.95 V vs SHE (−1.57 V vs Fc+/Fc) with a TOF = 16 s−1. The complex is also a precatalyst for photocatalystic hydrogen evolution when paired with fluorescein (chromophore) and triethylamine (sacrificial electron source) in a 1:1 ethanol:water mixture.