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Updated: Apr 30, 2026

Preparation of Polyoxometalate-based Photo-responsive Membranes for the Photo-activation of Manganese Oxide Catalysts
Published on: August 7, 2018
Activation of a water molecule using a mononuclear Mn complex: from Mn-aquo, to Mn-hydroxo, to Mn-oxyl via charge
Benedikt Lassalle-Kaiser1, Christelle Hureau2, Dimitrios A Pantazis3
1Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), UMR-CNRS 8182, Univ Paris Sud 11, F-91405 Orsay, France.
Abstract:
Activation of a water molecule by the electrochemical oxidation of a Mn-aquo complex accompanied by the loss of protons is reported. The sequential (2 × 1 electron/1 proton) and direct (2 electron/2 proton) proton-coupled electrochemical oxidation of a non-porphyrinic six-coordinated Mn(II)OH2 complex into a mononuclear Mn(O) complex is described. The intermediate Mn(III)OH2 and Mn(III)OH complexes are electrochemically prepared and analysed. Complete deprotonation of the coordinated water molecule in the Mn(O) complex is confirmed by electrochemical data while the analysis of EXAFS data reveals a gradual shortening of an Mn-O bond upon oxidation from Mn(II)OH2 to Mn(III)OH and Mn(O). Reactivity experiments, DFT calculations and XANES pre-edge features provide strong evidence that the bonding in Mn(O) is best characterized by a Mn(III)-oxyl description. Such oxyl species could play a crucial role in natural and artificial water splitting reactions. We provide here a synthetic example for such species, obtained by electrochemical activation of a water ligand.
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