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Electrocatalytic Hydrogen Production with a Molecular Cobalt Complex in Aqueous Solution
Author(s) -
Wilken Mona,
Siewert Inke
Publication year - 2020
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201901913
Subject(s) - chemistry , cobalt , ligand (biochemistry) , catalysis , deprotonation , protonation , pyridine , aqueous solution , solvent , hydrogen production , electrochemistry , photochemistry , medicinal chemistry , inorganic chemistry , organic chemistry , electrode , ion , biochemistry , receptor
Herein, we present the synthesis of a cobalt complex with a pentadentate ligand platform and its application in the electrochemical hydrogen evolution reaction ( L CF3 =2,6‐bis(methoxybis(4‐trifluormethyl‐1H‐imidazol‐2‐yl)methyl)pyridine). The complex is active in neutral to acidic solvent mixtures containing 50 % water. Electronic tuning in the ligand backbone, that is introduction of electron‐withdrawing CF 3 ‐groups, shifts the onset potential of the catalytic wave to less negative potentials. NMR and UV/Vis studies indicate that the Co III complex is deprotonated twice in the ligand backbone under neutral conditions. Reduction is accompanied by protonation, as indicated by pH‐dependent CV measurements, and the Co I state initiates catalysis. The result suggests that the pentadentate ligand is an ideal platform for cobalt catalysts in the oxidative and reductive water splitting reaction.