Hydrogen evolution reaction mediated by an all-sulfur trinuclear nickel complex

We report the synthesis and the characterization of a trinuclear nickel complex. Solid state and solution studies using X-ray diffraction, NMR and UV-vis spectroscopy highlight the square planar geometries around the metal centers and an all-sulfur coordination sphere. It exhibits significant electrocatalytic activity for hydrogen evolution in DMF using Et₃NHCl as the proton source. DFT studies suggest that sulfur atoms act as proton relay, as proposed in [NiFe] hydrogenases.