Monopyrrolotetrathiafulvalene-based supramolecular organogels: Multi-stimuli responsiveness and formation of charge-transfer salt gels

Abstract

Charge-transfer salts formed by the electron donor tetrathiafulvalene and electron acceptor halogen have been the focus of significant interest in constructing high conductivity supramolecular nano-materials. However, the stable supramolecular gel systems of TTF-X2 combinations with controlled self-assembly pathways cannot be accessed easily in solvents. In this context, a novel representative organogel system was constructed according to the crown ether-monopyrrolotetrathiafulvalene-l- glutamide triad. The formed gel exhibited multiple stimulus responses on various external stimuli, including temperature, sonication, anions and K+. This gel could be transformed into the charge transfer salt gel with I2, which was an important first example of the charge transfer salt gel of TTF with I2 in solvents. The same gel-gel transition was also induced by adding other inorganic oxidants (i.e., Ag+, Fe3+, Cu2+ and TFA) and π-electron acceptors (i.e., TCNQ and C60).