A nickel molecular electro-catalyst for generating hydrogen from acetic acid or water

The reaction of 2,3-bis(2-hydroxybenzylideneimino)-2,3-butenedinitrile (H2L) and Ni(CH3CO2)2·2H2O affords a nickel(II) complex [NiL] 1, a new molecular electrocatalyst, which has been determined by X-ray crystallography. Electrochemical studies show that complex 1 can catalyze hydrogen evolution from acetic acid or from water. Turnover frequency (TOF) reaches a maximum of 193 (in DMF) and 574 (in buffer, pH 6) moles of hydrogen per mole of catalyst per hour, respectively. Sustained proton reduction catalysis occurs at glassy carbon (GC) electrode to give H2 over a 42 h electrolysis period and no observable decomposition of the catalyst.