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Updated: May 13, 2025
![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)
Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
Published on: December 4, 2017
Effect of Ligand Backbone on the Electrochemical Hydrogen Evolution Reaction and Hydrogen-Atom-Transfer Reactivity
Sabarni Paul1, Subhankar Sutradhar2, Aniruddha Paik1
1Department of Chemistry, University of North Bengal, Darjeeling 734013, India.
Abstract:
Redox-active quinoline-containing [NiII(2PyN2Q) (H2O)]2+ complex (1) has been developed for the electrocatalytic (e) hydrogen evolution reaction (HER) in the presence of organic acids and water and for the hydrogen-atom-transfer (HAT) reaction with styrene in the presence of acids. Complex 1 shows promising e-HER performance in water up to pH 9. It exhibits a stepwise (E)ECEC mechanism with AcOH, while a potential-dependent bimolecular homolytic pathway and CEEC mechanism is operative with p-toluene sulfonic acid during the e-HER. The one- and two-electron-reduced species of 1 are characterized by spectro-electrochemistry, optical, and EPR studies. Moreover, the inverse kinetic isotope effect (KIE = 0.83) between AcOH and d4-AcOH during the e-HER and e-HAT with styrene for the hydro-functionalization reaction using catalyst 1 possibly suggests the involvement of nickel hydride species. The e-HER and e-HAT reactivity of 1 have been compared with redox-inactive redox-inactive [NiII(N4Py)(H2O)]2+ (2), demonstrating the prominent effect of quinoline in the e-HER and pyridine in the e-HAT. The proposed mechanism of the e-HER with AcOH is well supported by DFT studies.
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