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

Isidoro López 1 Rui Cao 2 David A. Quist 2 Kenneth D Karlin 2 Nicolas Le Poul 1
1 CEMCA - Chimie, Electrochimie Moléculaires et Chimie Analytique
2 JHU - Johns Hopkins University
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.
Keywords : oxygen reduction/evolution cyclic voltammetry copper reduction potential reorganization energy
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Article dans une revue
Chemistry - A European Journal, Wiley-VCH Verlag, 2017, chemistry, a european journal, 23 (72), pp.18314-18319. 〈https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201705066〉. 〈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 : mercredi 25 avril 2018 - 10:28:58

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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, chemistry, a european journal, 23 (72), pp.18314-18319. 〈https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201705066〉. 〈10.1002/chem.201705066〉. 〈hal-01636273〉

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