A molecular iron(III) electrocatalyst supported by amine-bis(phenolate) ligand for water reduction

• Reaction of amine-bis(phenolate) ligand (H2L) and FeCl3 gives a new Fe(III) complex, [L2Fe2(CH3O)2] 1.
• Structure of 1 is determined by single crystal X-ray diffraction analysis.
• 1 can catalyze water-reduction, with a TOF of 1076.5 mol/h at an overpotential of 896.8 mV (buffer, pH 7.0).

A new molecular catalyst based on a dinuclear iron complex [L2Fe2(CH3O)2] 1 is formed by the reaction of 2-pyridylamino-N,N-bis(2-methylene-4,6-bimethyl)phenol (H2L) with FeCl3 for electrolytic hydrogen evolution both from acetic acid and water. Turnover frequency (TOF) reaches a maximum of 84.5 mol of hydrogen per mole of catalyst per hour at an overpotential of 941.6 mV (in DMF) and 1076.5 mol of hydrogen per mole of catalyst per hour at an overpotential of 896.8 mV (in buffer, pH 7.0), respectively. Sustained water reduction catalysis occurs at glassy carbon to give H2 over a 1 h electrolysis period with 94.5% Faradaic yield.

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