Supramolecular Host-Guest Hydrogel Based on γ-Cyclodextrin and Carboxybenzyl Viologen Showing Reversible...

Much effort has been devoted to the development of supramolecular hydrogels due to their broad applications and conveniently controllable properties. Here, we demonstrate a novel supramolecular host-guest hydrogel, which is constructed by the host γ-CD complexed with the guest 1-(4-carboxybenzyl)-4,4'-bipyridinium chloride (1·Cl^-) through the π···π interaction, hydrogen bonding, and host-guest interactions. The supramolecular hydrogel [1@γ-CD] exhibits reversible electron transfer photochromic behavior and photomodulable fluorescence. The excellent photochromic and fluorescence properties support the practical utility of the supramolecular hydrogel as a visual display and anti-counterfeiting material.