Electrocatalytic Hydrogen Evolution by Cobalt Complexes with a Redox Non-Innocent Polypyridine Ligand

Liu J, Liao RZ, Heinemann FW, Meyer K, Thummel RP, Zhang Y, Tong L (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Inorganic Chemistry American Chemical Society

DOI: 10.1021/acs.inorgchem.1c02539

Abstract

Novel cobalt and zinc complexes with the tetradentate ppq (8-(1″,10″-phenanthrol-2″-yl)-2-(pyrid-2′-yl)quinoline) ligand have been synthesized and fully characterized. Electrochemical measurements have shown that the formal monovalent complex [Co(ppq)(PPh3)]+ (2) undergoes two stepwise ligand-based electroreductions in DMF, affording a [Co(ppq)DMF]-1 species. Theoretical calculations have described the electronic structure of [Co(ppq)DMF]-1 as a low-spin Co(II) center coupling with a triple-reduced ppq radical ligand. In the presence of triethylammonium as the proton donor, the cobalt complex efficiently drives electrocatalytic hydrogen evolution with a maximum turnover frequency of thousands per second. A mechanistic investigation proposes an EECC H2-evolving pathway, where the second ligand-based redox process (E), generating the [Co(ppq)DMF]-1 intermediate, initiates proton reduction, and the second proton transfer process (C) is the rate-determining step. This work provides a unique example for understanding the role of redox-active ligands in electrocatalytic H2 evolution by transition metal sites.

Authors with CRIS profile

Frank Wilhelm Heinemann Lehrstuhl für Anorganische und Allgemeine Chemie Karsten Meyer Lehrstuhl für Anorganische und Allgemeine Chemie

Involved external institutions

Huazhong University of Science & Technology CN China (CN) University of Houston US United States (USA) (US) Guangzhou University CN China (CN)

How to cite

APA:

Liu, J., Liao, R.Z., Heinemann, F.W., Meyer, K., Thummel, R.P., Zhang, Y., & Tong, L. (2021). Electrocatalytic Hydrogen Evolution by Cobalt Complexes with a Redox Non-Innocent Polypyridine Ligand. Inorganic Chemistry. https://dx.doi.org/10.1021/acs.inorgchem.1c02539

MLA:

Liu, Jiale, et al. "Electrocatalytic Hydrogen Evolution by Cobalt Complexes with a Redox Non-Innocent Polypyridine Ligand." Inorganic Chemistry (2021).

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