ORCID Profile
0000-0003-1803-6733
Current Organisation
École Normale Supérieure
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Publisher: American Chemical Society (ACS)
Date: 26-09-2022
DOI: 10.1021/JACS.2C07196
Abstract: We herein report the synthesis and magnetic properties of a Ni(II)-porphyrin tethered to an imidazole ligand through a flexible electron-responsive mechanical hinge. The latter is capable of undergoing a large litude and fully reversible folding motion under the effect of electrical stimulation. This redox-triggered movement is exploited to force the axial coordination of the appended imidazole ligand onto the square-planar Ni(II) center, resulting in a change in its spin state from low spin (
Publisher: Elsevier BV
Date: 09-2019
Publisher: Wiley
Date: 02-01-2019
Abstract: A dynamic supramolecular approach is developed to promote the π-dimerization of viologen radicals at room temperature and in standard concentration ranges. The approach involves cis- or trans-protected palladium centers serving as inorganic hinges linking two functionalized viologens endowed with metal-ion coordinating properties. Based on detailed spectroscopic, electrochemical and computational data, we show that the one-electron electrochemical reduction of the viologen units in different dynamic metal/ligand mixtures leads to the formation of the same intramolecular π-dimer, regardless of the initial environment around the metallic precursor and of the relative ratio between metal and ligand initially introduced in solution. The large-scale electron-triggered reorganization of the building blocks introduced in solution thus involves drastic changes in the stoichiometry and stereochemistry of the palladium/viologen complexes proceeding in some cases through a palladium centered trans→cis isomerization of the coordinated ligands.
Publisher: American Chemical Society (ACS)
Date: 21-12-2022
Publisher: The Electrochemical Society
Date: 30-05-2021
DOI: 10.1149/MA2021-0116778MTGABS
Abstract: Stimuli-responsive self-assembled molecular materials are currently subject to intense research activity. This growing interest stems largely from the myriad of exciting applications envisioned for dynamic supramolecular assemblies, also known as dynamers, in materials science, sensing, catalysis and electronics. Enormous technologic interests are for instance at stake in being able to devise molecular objects that could respond to external stimuli by changes in structure and function. These particular properties can lead to applications in various domains as (i) in molecular electronics, (ii) in analytic science, with switchable hosts allowing the controlled binding/release of pollutants or drugs, (iii) in materials science with the development of adaptive supramolecular polymers. Our group has been focusing over the past few years on the development of tailor-made redox-controllable molecular and supramolecular systems involving electrogenerated pi-radicals as key responsive and/or assembling elements [1-3]. In this lecture, we will focus on the physico-chemical properties of a series of porphyrin-based molecular tectons whose self-assembly can be controlled with optical or electrical stimulus. The dynamic properties of these stimuli-responsive molecular architectures and molecular materials will mainly be discussed on the basis of electrochemical, spectroelectrochemical and ESR experiments supported by quantum chemical calculations [4-7]. References [1] C. Kahlfuss, E. Saint-Aman, C. Bucher (2016). Redox-controlled intramolecular motions triggered by π-dimerization and πmerization processes In T. Nishinaga (Ed.), Organic Redox Systems: Synthesis, Properties, and Applications (pp. 39). New-York: John Wiley and sons. [2] H. D. Correia, S. Chowdhury, A. P. Ramos, L. Guy, G. J.-F. Demets, C. Bucher, Polymer International 68, 572 (2019). [3] G. Brunet, E. A. Suturina, G. P. C. George, J. S. Ovens, C. Bucher, M. Murugesu, Chemistry - A European Journal, DOI: 10.1002/chem.202003073 (2020). [4] S. Chowdhury, Y. Nassar, L. Guy, D. Frath, F. Chevallier, E. Dumont, A. P. Ramos, G. J.-F. Demets, C. Bucher, Electrochimica Acta 316, 79 (2019). [5] C. Kahlfuss, S. Denis-Quanquin, N. Calin, E. Dumont, M. Garavelli, G. Royal, S. Cobo, E. Saint-Aman, C. Bucher, Journal of the American Chemical Society 138, 15234−15242 (2016). [6] C. Kahlfuss, T. Gibaud, S. Denis-Quanquin, S. Chowdhury, G. Royal, F. Chevallier, E. Saint-Aman, C. Bucher, Chemistry - A European Journal 24, 13009 (2018). [7] C. Kahlfuss, R. Gruber, E. Dumont, G. Royal, F. Chevallier, E. Saint-Aman, C. Bucher, Chemistry - A European Journal 25, 1573 (2019).
Publisher: Wiley
Date: 10-02-2022
Abstract: CF 3 ‐substituted porphyrins have attracted increasing interest over the past decade. However, the number of ex les reported in the literature remains quite limited and much remains to be done to understand the properties and reactivity of these molecules. We are now reporting on the synthesis of a series of free base porphyrins incorporating one, two and three CF 3 substituents, including the 5,10,15‐tris(CF 3 ) substituted porphyrin which has never been described before. We have also carried out detailed electrochemical and spectroscopic analyses aiming at assessing the electron‐withdrawing properties of the CF 3 substituents compared to the widely used C 6 F 5 . Our studies led us to propose an interpretation of the quite unusual electrochemical signature of these molecules featuring three successive one‐electron reduction waves.
Publisher: American Chemical Society (ACS)
Date: 12-10-2020
Publisher: American Chemical Society (ACS)
Date: 14-11-2016
DOI: 10.1021/JACS.6B09311
Abstract: Viologen-centered electron transfer is used to trigger a complete dissociation of a porphyrin-based supramolecular architecture. In the oxidized state, self-assembly is induced by iterative association of in idual porphyrin-based tectons. Dissociation of the self-assembled species is actuated upon changing the redox state of the bipyridium units involved in the tectons from their dicationic state to their radical cation state, the driving force of the disassembling process being the formation of an intramolecularly locked conformation partly stabilized by π-dimerization of both viologen cation radicals.
Publisher: American Chemical Society (ACS)
Date: 23-02-2021
No related grants have been discovered for christophe BUCHER.