Highly efficient artificial light-harvesting systems constructed in aqueous solution for supramolecular photocatalysis

Abstract

Two highly efficient artificial light-harvesting systems (ALHSs) based on supramolecular strategy have been successfully fabricated by water-soluble pillar[5]arene (WP5), a bola-type salicylaldehyde-azine derivative (HNPD), and two different hydrophobic fluorescent dyes (Eosin Y (ESY) and Nile Red (NiR)). The constructed ALHSs show high antenna effect (32.5 for the WP5⊃HNPD-ESY assembly and 30.1 for the WP5⊃HNPD-NiR assembly) with the donor/acceptor ratio of [HNPD]/[ESY] ​= ​250:1 and [HNPD]/[NiR] ​= ​200:1, respectively. Significantly, the formed WP5⊃HNPD supramolecular nanoparticles perform an enhanced aggregation-induced emission (AIE) effect and can serve as an excellent energy donor to realize the energy transfer from the WP5⊃HNPD assembly to ESY and NiR in aqueous phase, respectively. Moreover, inspired by natural photosynthesis system, the WP5⊃HNPD-ESY and WP5⊃HNPD-NiR nanoparticles were further used to realize the photocatalytic dehalogenation reaction of α-bromoacetophenone in aqueous environment with moderate yields of 55% and 65%, suggesting that the solar energy was successfully harvested and effectively converted into chemical energy. This work not only provides a novel approach for the fabrication of highly efficient ALHSs in aqueous phase, but also successfully applies the output energy for the photocatalytic dehalogenation reaction of α-bromoacetophenone, showing a potential application in mimicking natural photosynthesis system.