Issue 10, 2018

Intramolecular hydrogen-bonding in a cobalt aqua complex and electrochemical water oxidation activity

Abstract

Water oxidation is catalysed in Nature by a redox cofactor embedded in a hydrogen-bonded network designed to orchestrate proton transfer throughout the challenging 4 electron reaction. In order to mimic aspects of this microenvironment, [CoLDMA(CH3CN)2][BF4]2 (2) was synthesized, where LDMA is a dipyridyldiamine ligand with two dimethylamine bases in the secondary coordination sphere. Structural characterization of the corresponding aqua complexes establish hydrogen bonding between the bound water and pendant base(s). Cyclic voltammetry of [CoLDMA(CH3CN)2][BF4]2 (2) reveals enhanced oxidative current upon titration with water and controlled potential electrolysis confirms evolution of O2. The related complex [CoLH(CH3CN)2][BF4]2 (1), which has the same primary coordination environment as 2 but lacks pendant bases, is inactive. The structural and electrochemical studies illustrate the role positioned proton relays can play in promoting redox reactivity.

Graphical abstract: Intramolecular hydrogen-bonding in a cobalt aqua complex and electrochemical water oxidation activity

Supplementary files

Article information

Article type
Edge Article
Submitted
18 Nov 2017
Accepted
05 Feb 2018
First published
06 Feb 2018
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2018,9, 2750-2755

Intramolecular hydrogen-bonding in a cobalt aqua complex and electrochemical water oxidation activity

J. F. Khosrowabadi Kotyk, C. M. Hanna, R. L. Combs, J. W. Ziller and J. Y. Yang, Chem. Sci., 2018, 9, 2750 DOI: 10.1039/C7SC04960A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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