Electrostatic Effects on Proton Coupled Electron Transfer in Oxomanganese Complexes Inspired by the Oxygen-Evolving Complex of Photosystem II

Abstract

Electrostatic Effects on Proton Coupled Electron Transfer in Oxomanganese Complexes Inspired by the Oxygen-Evolving Complex of Photosystem II

Publication
Journal of Physical Chemistry B
Date
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The influence of electrostatic interactions on the free energy of proton coupled electron transfer in biomimetic oxomanganese complexes inspired by the oxygen-evolving complex (OEC) of photosystem II (PSII) are investigated. The reported study introduces an enhanced multiconformer continuum electrostatics (MCCE) model, parametrized at the density functional theory (DFT) level with a classical valence model for the oxomanganese core. The calculated pKa’s and oxidation midpoint potentials (Em’s) match experimental values for eight complexes, indicating that purely electrostatic contributions account for most of the observed couplings between deprotonation and oxidation state transitions.