Liens transverses ENS de Lyon

Agenda de l'ENS de Lyon

Electron-Triggered Metamorphism in Viologen Based Self-Assembled Supramolecular Materials

ven 09 oct 2020



Salle André Collet


Soutenance de M. Shagor CHOWDHURY sous la Direction de M. Christophe BUCHER

Langue(s) des interventions

Description générale

The aim of my PhD work was to develop new approaches towards “smart” molecular and/or supramolecular materials displaying redox‐responsive properties. The objective of our work was to develop new molecular and supramolecular structures whose structure and/or self-assembly can be controlled by electrical stimulations. One of the challenges was to broaden the range of molecules and organizations that can be controlled by an external stimulus. In this work, we have developed molecular and supramolecular systems that can be stimulated by electron transfer, by addition of chemical reducing agents or by light irradiation. The main driving force exploited to achieve stimuli-triggered molecular and supramolecular metamorphic processes was the non‐covalent and fully reversible -dimerization of bipyridinium cation radicals. The first part of this PhD thesis is devoted to the synthesis and properties of molecular tectons incorporating one metalloporphyrin and two or four 4,4’-bipyridium units. These key building elements have for instance been shown to enable the formation of redox-switchable supramolecular assemblies in the presence of cucurbituril cavitands. The second part deals with the development of redox-responsive molecular clips and tweezers, with a particular focus on their recognition and self-assembly properties in the presence of a guest moiety. The last part describes the formation of redox-responsive coordination polymers built by assembly of a ditopic 4,4’-bipyridium-based ligand with palladium, used as a dynamic inorganic hinge. Our results support the conclusion that the formation of coordination polymers/oligomers in solution can be controlled by suitable electrical stimulations.

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