Electrocatalytic H 2 evolution promoted by a bioinspired (N2S2)Ni(II) complex.

A bioinspired (N2S2)Ni(II) electrocatalyst is reported that produces H ₂ from CF ₃ CO ₂ H with a turnover frequency (TOF) of ∼1250 s ^-1 at low acid concentration (<0.043 M) in MeCN. A mechanism for the H ₂ production by this electrocatalyst is proposed and its activity is benchmarked against those of other reported molecular Ni H ₂ evolution electrocatalysts. The involvement of a hemilabile pyridyl group of the N2S2 ligand is proposed to mimic the role of a cysteine residue involved in the biological proton reduction performed by [NiFe] hydrogenases.