Reducing systematic uncertainty in computed redox potentials for aqueous transition-metal-substituted polyoxotungstates

Thompson, J. A., González-Cabaleiro, R. and Vilà-Nadal, L. (2023) Reducing systematic uncertainty in computed redox potentials for aqueous transition-metal-substituted polyoxotungstates. Inorganic Chemistry, 62(31), pp. 12260-12271. (doi: 10.1021/acs.inorgchem.3c01115) (PMID:37489885)

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Abstract

Polyoxometalates have attracted significant interest owing to their structural diversity, redox stability, and functionality at the nanoscale. In this work, density functional theory calculations have been employed to systematically study the accuracy of various exchange–correlation functionals in reproducing experimental redox potentials, U0Red in [PW11M(H2O)O39]q− M = Mn(III/II), Fe(III/II), Co(III/II), and Ru(III/II). U0Red calculations for [PW11M(H2O)O39]q− were calculated using a conductor-like screening model to neutralize the charge in the cluster. We explicitly located K+ counterions which induced positive shifting of potentials by > 500 mV. This approximation improved the reproduction of redox potentials for Kx[XW11M(H2O)O39]q−x M = Mn(III/II)/Co(III/II). However, uncertainties in U0Red for Kx[PW11M(H2O)O39]q−x M = Fe(III/II)/Ru(III/II) were observed because of the over-stabilization of the ion-pairs. Hybrid functionals exceeding 25% Hartree–Fock exchange are not recommended because of large uncertainties in ΔU0Red attributed to exaggerated proximity of the ion-pairs. Our results emphasize that understanding the nature of the electrode and electrolyte environment is essential to obtain a reasonable agreement between theoretical and experimental results.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Vila-Nadal, Dr Laia and Thompson, Jake
Authors: Thompson, J. A., González-Cabaleiro, R., and Vilà-Nadal, L.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Inorganic Chemistry
Publisher:American Chemical Society
ISSN:0020-1669
ISSN (Online):1520-510X
Published Online:25 July 2023
Copyright Holders:Copyright © 2023 The Authors
First Published:First published in Inorganic Chemistry 62:12260–12271
Publisher Policy:Reproduced under a Creative Commons License

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