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  • Redox-Induced Molecular Metamorphism Promoting a Sol/Gel Phase Transition in a Viologen-Based Coordination Polymer.

Redox-Induced Molecular Metamorphism Promoting a Sol/Gel Phase Transition in a Viologen-Based Coordination Polymer.

Chemistry (Weinheim an der Bergstrasse, Germany) (2018-07-28)
Christophe Kahlfuss, Thomas Gibaud, Sandrine Denis-Quanquin, Shagor Chowdhury, Guy Royal, Floris Chevallier, Eric Saint-Aman, Christophe Bucher
ABSTRACT

We have developed a strategy enabling control over the organization of ditopic molecular tectons within a palladium-based self-assembled system. The key electron-responsive sub-unit is a viologen-based mechanical hinge that can toggle under electric stimulation between a folded and a stretched position, the driving force of the folding motion being the π-dimerisation of the electrogenerated viologen cation radicals. The title ditopic tecton features two planar, N2-type, triazole/pyridine-based bidentate binding units, providing the tecton with the ability to chelate two palladium ions both in its folded and in its elongated conformations. Association of this ditopic redox-responsive tecton with palladium to form 1D self-assembled architectures undergoing large scale reorganizations in solution under electric stimulation, has been established on the ground of spectroscopic, electrochemical, spectro-electrochemical and rheological data. Our result reveal that addition of metal leads to a significant stabilization of the π-dimer species in solution and that the redox-triggered reorganisation of the tectons comes along in suitable conditions with a macroscopic sol/gel-type phase transition.

MATERIALS
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Brand
Product Description

Sigma-Aldrich
4,4′−Dipyridyl, 98%