Visible-Light-Regulated Supramolecular Dendritic Organogels Based on Halogen Bonding

Photoresponsive supramolecular gels have garnered significant research interest owing to their wide-ranging applications. However, most existing systems rely on UV light irradiation, which poses potential health risks and environmental concerns. The halogen bond, characterized by its high directionality, tunable interaction strength, excellent hydrophobicity, and the substantial size of halogen atoms, represents a crucial driving force in supramolecular assembly. Nevertheless, the development of visible-light-responsive gels mediated by halogen bonding remains a considerable challenge. In this study, we successfully constructed such a system by employing pyridine-cored dendritic ligands (Py-n, where n = 1 or 2) as halogen bond acceptors and 1,2-bis(2,3,5,6-tetrafluoro-4-iodophenyl)diazene (BTFIPD) as both the halogen bond donor and the visible-light-responsive unit. Remarkably, the resulting supramolecular gel demonstrated an efficient gel-to-sol transition upon green light irradiation. This work establishes an environmentally benign, visible-light-mediated strategy for modulating supramolecular phase transitions, showcasing considerable potential for applications in photoelectrical nanodevices and information storage technologies.