Construction of Artificial Light-Harvesting Systems Based on Aggregation-Induced Emission Type Supramolecular Self-Assembly Metallogels

A method for preparing new artificial light-harvesting systems (ALHSs) based on supramolecular metallogels was proposed. Various metal ions were introduced into a solution of a bi-benzimidazole compound (P) in ethylene glycol, and P exhibited high selectivity toward Al³⁺, as indicated by the noticeable red shift (49 nm) observed in the fluorescence spectra of P after the addition of Al³⁺. Interestingly, the gelator, P, could self-assemble into a stable supramolecular gel (P-gel) that exhibits strong aggregation-induced emission in ethylene glycol. Thus, two ALHSs were successfully prepared in a gel environment. The P–Al³⁺ assembly acts as the donor in the ALHSs, while BODIPY 505/515 (BDP) and rhodamine 6G (Rh6G), which are loaded onto the P–Al³⁺ assembly, act as acceptors. In these two diverse systems, the occurrence of an energy transfer process is confirmed from the P–Al³⁺ assembly to BDP and Rh6G. The findings of this study will enable the design and fabrication of ALHSs.