Modulating Fluorescent and Chiral Properties of Luminescent Self-Assemblies by Supramolecular Interactions

In recent years, the regulation of chiral fluorescent self-assembly via dynamic and controllable supramolecular interactions has emerged as an effective strategy for the construction of intelligent luminescent materials. Herein, a luminescent chiral self-assembly system with tunable fluorescence and chiral properties was developed based on pillararene. A chiral luminescent molecule BPY-Chol was synthesized by grafting the chiral unit cholesterol onto a bipyridine derivative with blue emission. It can self-assemble into helical structures in chloroform. The coassembly of 1,4-dimethoxypillar[5]arene (DMP5) and BPY-Chol into helical structures was driven by π-π interaction, through a simple mixing process in chloroform, accompanied by chiral inversion and a decrease in fluorescence intensity. Under acidic conditions, BPY-Chol was protonated to H-BPY-Chol, and the chirality was inversed, accompanied by a red-shift phenomenon and enhancement in its fluorescence emission. Upon complexation between H-BPY-Chol and DMP5, the morphology turned to nanosheet structures, which was accompanied by turning off both chiral and fluorescence signals. Further, this regulatable luminescent chiral self-assembly system was successfully applied in the field of information encryption.