Mononuclear Fe(III) Schiff base antipyrine complexes for catalytic hydrogen generation.

Mononuclear Fe(III) complexes containing an antipyrine Schiff base ligand were prepared and fully characterized, demonstrating a planar tetradentate coordination geometry. These complexes were found to be active for the hydrogen evolution reaction. Catalysis occurs at -1.4 V Fc/Fc, with an overpotential of 700 mV. The complexes are active electrocatalysts with a turnover frequency of 700 s. Furthermore, when paired with a chromophore and sacrificial donor, the complexes are active photocatalysts demonstrating >1700 turnovers during 40 hours of irradiation with a quantum yield of up to 5.4%. The catalysts have also been found to operate in natural water samples of varying salinity.