Electrocatalytic Hydrogen Evolution at Low Overpotentials by Cobalt Macrocyclic Glyoxime and Tetraimine Complexes

Electrocatalytic hydrogen evolution by cobalt difluoroboryl-diglyoximate complexes.

In the presence of moderately strong acids in CH3CN, cobalt complexes with BF2-bridged diglyoxime ligands are active catalysts for the reduction of protons to H2 at potentials as positive as -0.28 V vs. SCE.

Hydrogen evolution by cobalt tetraimine catalysts adsorbed on electrode surfaces.

Aryl-substituted tetraimine complexes related to Co(dmgBF(2))(2)(MeCN)(2) (dmg = dimethylglyoxime) were synthesized and are active for hydrogen evolution. Co(dmgBF(2))(2)(MeCN)(2) can be adsorbed to a glassy carbon electrode. The chemically modified electrode is active for hydrogen evolution in aqueous solution at pH < 4.5, with an overpotential of only 100 mV.

Reversible electrocatalytic production and oxidation of hydrogen at low overpotentials by a functional hydrogenase mimic.

Hydrogen generation catalyzed by fluorinated diglyoxime-iron complexes at low overpotentials.

Fe(II) complexes containing the fluorinated ligand 1,2-bis(perfluorophenyl)ethane-1,2-dionedioxime (dAr(F)gH(2); H = dissociable proton) exhibit relatively positive Fe(II/I) reduction potentials. The air-stable difluoroborated species [(dAr(F)gBF(2))(2)Fe(py)(2)] (2) electrocatalyzes H(2) generation at -0.9 V vs SCE with i(cat)/i(p) ≈ 4, corresponding to a turnover frequency (TOF) of ∼20 s(-1) ...

Electrocatalytic hydrogen evolution in acidic water with molecular cobalt tetraazamacrocycles.

A series of water-soluble molecular cobalt complexes of tetraazamacrocyclic ligands are reported for the electrocatalytic production of H(2) from pH 2.2 aqueous solutions. The comparative data reported for this family of complexes shed light on their relative efficiencies for hydrogen evolution in water. Rotating disk electrode voltammetry data are presented for each of the complexes discussed,...