Synthesis and electrocatalytic function for hydrogen generation of cobalt and nickel complexes supported by phenylenediamine ligand

•Reactions of H2L, with Co(ClO4)2 or Ni(ClO4)2 affords two complexes [L-M] (M = Co, 1; Ni, 2).•1 and 2 electrocatalyze H2 generation from CH3COOH and H2O.•The nickel center constitutes the better active catalyst.

To study the effect of different metal centers on catalytic function, two complexes [L-M] (M = Co, 1; Ni, 2) were prepared by the reactions of N,N′-bis(2-amino-3,5-di-tert-butylphenyl)-o-phenylenediamine, H2L, with Co(ClO4)2·6H2O or Ni(ClO4)2·6H2O, respectively. Electrochemical investigations show 1 and 2 can electrocatalyze hydrogen generation both from acetic acid and aqueous buffer. Complexes 1 and 2 afford a turnover frequency (TOF) of 738.23 and 1331.23 mol of hydrogen per mole of catalyst per hour (mol h− 1) at an overpotential (OP) of 0.838 V from a neutral buffer, respectively, indicating that the nickel center constitutes the better active catalyst.

Graphical abstractReactions of N,N′-bis(2-amino-3,5-di-tert-butylphenyl)-o-phenylenediamine, H2L, with Co(ClO4)2·6H2O or Ni(ClO4)2·6H2O affords two complexes [L-M] (M = Co, 1; Ni, 2), which can electrocatalyze hydrogen generation both from acetic acid and aqueous buffer solution.Figure optionsDownload full-size imageDownload as PowerPoint slide