Direct Determination of Electron-Transfer Properties of Dicopper-Bound Reduced Dioxygen Species by a Cryo-Spectroelectrochemical Approach.

Abstract : Direct experimental determination of redox properties of superoxo (O2*-) and peroxo (O22-) embedded in dicopper complexes bearing an unsymmetrical binucleating ligand was achieved using cryo-electrochemistry and cryo-spectroelectrochemistry in dichloromethane. Cyclic voltammetry for dicopper(I) (1+) oxidation to a Cu(I)Cu(II) mixed-valent species (12+) under inert atmosphere reveals slow heterogeneous electron-transfer kinetics, indicative of a large reorganization energy. Oxygenation of the dicuprous complex 1+ gives the bridged peroxo dicopper(II) species 3+ which is reversibly oxidized to the superoxo complex 22+ at E0 = 0.11 V (vs SCE) with a small inner sphere electron-transfer reorganization energy, lambda_i = 0.54 eV, determined from variable temperature electrochemical impedance spectroscopy. The data suggest that the O2*-/O22- redox process occurs directly on the O2-derived core.
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Chemistry - A European Journal, Wiley-VCH Verlag, 2017, 〈10.1002/chem.201705066〉
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http://hal.univ-brest.fr/hal-01636273
Contributeur : Nicolas Renard <>
Soumis le : jeudi 16 novembre 2017 - 13:27:29
Dernière modification le : jeudi 11 janvier 2018 - 12:32:24

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Isidoro López, Rui Cao, David A. Quist, Kenneth D Karlin, Nicolas Le Poul. Direct Determination of Electron-Transfer Properties of Dicopper-Bound Reduced Dioxygen Species by a Cryo-Spectroelectrochemical Approach.. Chemistry - A European Journal, Wiley-VCH Verlag, 2017, 〈10.1002/chem.201705066〉. 〈hal-01636273〉

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