Issue 31, 2018

Electrochemical water oxidation using a copper complex

Abstract

Herein, we report the application of the mononuclear copper complex 1, [CuII(L)]2+, in electrochemical water oxidation catalysis (L = 1,3-bis(((1-methyl-1H-imidazol-2-yl)methyl)amino)propan-2-ol). The complex exhibits a N4 donor set consisting of two amine and two imidazole units and a dangling OH unit in close proximity to the copper ion. 1 exhibits a moderate apparent rate constant kcat of 0.12 s−1 in catalysis and operates at an overpotential of 0.83 V. Detailed investigations allowed us to derive a mechanism for water oxidation. The catalysis proceeds only under basic conditions, where [CuII(L)(OH)]+, 1H−1, is the main solution species, which indicates that a negatively charged ligand is necessary to drive the catalysis. Initial oxidation of 1H−1 is coupled to proton loss forming a copper(III) species and further oxidation initiates oxygen evolution. Initial oxidation of 1 under neutral, i.e. non-catalytic, conditions is pH independent, highlighting the importance of PCET steps during catalysis. We collected reasonable evidence that catalysis proceeds via a water nucleophilic attack mechanism. The electrolyte presumably acts as a proton acceptor in catalysis as the onset potential depends on the buffer employed.

Graphical abstract: Electrochemical water oxidation using a copper complex

Supplementary files

Article information

Article type
Paper
Submitted
05 Apr 2018
Accepted
07 Jun 2018
First published
07 Jun 2018
This article is Open Access
Creative Commons BY-NC license

Dalton Trans., 2018,47, 10737-10741

Electrochemical water oxidation using a copper complex

S. Nestke, E. Ronge and I. Siewert, Dalton Trans., 2018, 47, 10737 DOI: 10.1039/C8DT01323C

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements