Bulletin of the Korean Chemical Society, 10(42), p. 1364-1367, 2021
DOI: 10.1002/bkcs.12373
Electrochemical proton reduction is a promising energy storage method because H2 molecule has a simple structure with a relatively low potential energy. Current interest in hydrogen catalysts has increased research efforts on synthetic analogs of hydrogenase active sites. In this study, we demonstrated the electrochemical H2 evolution reactivity of [NNNR‐Co(CH3CN)3]2+ (R CH2 (1b), NCH3 (2b)) complexes and examined a proton‐relay process in the H2 evolution reaction (HER). Upon one‐electron reduction, the Co(II) ion center in a high‐spin state dissociated a CH3CN ligand, while opening a reaction site. Cyclic voltammograms of the Co complexes indicated quasi‐reversible Co(II/I) redox behaviors, and both complexes 1b and 2b showed catalytic H2 evolution activity. Interestingly, 2b, assisted by a proton‐relaying NCH3 group, exhibited more efficient catalytic activity than 1b.