Keynote speakers > Nicolas LE POUL

Dioxygen Activation by Copper Complexes: Electrochemical and Spectroelectrochemical Approaches

Dr. Nicolas LE POUL

Laboratoire CEMCA, UMR CNRS 6521, Université de Bretagne Occidentale, 29238 Brest, France
nicolas.lepoul@univ-brest.fr

Biosketch:

Nicolas Le Poul received his PhD from the University of Exeter (UK) in 2002 under the supervision of Dr. Stephen J. Green on the low-temperature electrochemistry of cuprate-based superconductors. After two successive post-doctoral experiences in the teams of Pr. Jean-Marie Tarascon (Amiens, France, 2002) and Dr. Yves Le Mest (Brest, France, 2004), he was appointed CNRS junior researcher at the CEMCA laboratory (Brest) in 2006, then CNRS senior researcher in 2023. His main research interests are electrochemistry of coordination compounds for electrocatalysis, development of in-situ cryo-spectroelectrochemical methods, and electrode functionalization.

Summary:

The development of energy-efficient, environmentally benign and cost-effective catalysts which can selectively oxidize C-H bond of alkanes, such as methane, from clean oxidant (O₂) remains a formidable social challenge. For that purpose, many molecular Cu-based complexes inspired from the active site of copper oxygenases have been designed over the past decades.^[1] Recent works have particularly emphasized that H-Atom Abstraction (HAA) from strong C-H bonds of hydrogenated substrates could be obtained with [Cu^IIO₂^·-], [Cu^IIO^·] and [Cu^III(OH)] cores,^[2] as well as dinuclear mixed-valent [Cu^III(μ-O(H))Cu^II] species.^[3-5] Nevertheless, one main issue to address is to better clarify the relationships between the structural features of these active copper-oxygen adducts and their thermodynamic/kinetic/reactivity properties towards alkanes. In particular, it is necessary to determine how the ligand field affects thermochemical properties of the Cu catalysts and orientates towards stepwise or concerted proton-coupled electron transfers. So far, this understanding is mainly impaired by the lack of thermodynamic data (redox, pKa) for copper-oxygen adducts, because of their high instability. In this context, we have developed an original cryo-spectroelectrochemical approach which allows the in-situ generation and time-resolved characterization of these transient copper-oxygen species. This set-up also affords the determination of redox properties in terms of thermodynamics and electron-transfer kinetics.^[6-8]

[1] J. De Tovar, R. Leblay, Y. Wang, L. Wojcik, A. Thibon-Pourret, M. Reglier, A. J. Simaan, N. Le Poul, C. Belle, Chem. Sci. 2024, 15, 10308-10349.

[2] N. Gagnon, W. B. Tolman, Acc. Chem. Res. 2015, 48, 2126-2131.

[3] J. A. Isaac, A. Thibon-Pourret, A. Durand, C. Philouze, N. Le Poul, C. Belle, Chem. Commun. 2019, 55, 12711-12714.

[4] A. Thibon-Pourret, F. Gennarini, R. David, J. A. Isaac, I. Lopez, G. Gellon, F. Molton, L. Wojcik, C. Philouze, D. Flot, Y. Le Mest, M. Reglier, N. Le Poul, H. Jamet, C. Belle, Inorg. Chem. 2018, 57, 12364-12375.

[5] A. Kochem, F. Gennarini, M. Yemloul, M. Orio, N. Le Poul, E. Riviere, M. Giorgi, B. Faure, Y. Le Mest, M. Reglier, A. J. Simaan, Chempluschem 2017, 82, 615-624.

[6] I. Lopez, R. Cao, D. A. Quist, K. D. Karlin, N. Le Poul, Chem. Eur. J. 2017, 23, 18314-18319.

[7] I. López, N. Le Poul, Coord. Chem. Rev. 2021, 436, 213823-213845.

[8] P. K. Hota, A. Jose, S. Panda, E. M. Dunietz, A. E. Herzog, L. Wojcik, N. Le Poul, C. Belle, E. I. Solomon, K. D. Karlin J. Am. Chem. Soc. 2024, 146, 13066-13082.