Enhanced Singlet Oxygen Production in Supramolecular Artificial Light-Harvesting System for Photooxidation of 4-(Methylthio)toluene

An enhanced singlet oxygen (¹O₂) production artificial light-harvesting systems (LHSs) was constructed by supramolecular assembly of water-soluble pillar[5]arene (WP5) and naphthylhydroxyphenyl derivative (NHD). After WP5 and NHD binding to form WP5-NHD amphiphiles, WP5-NHD complex self-assembled to WP5-NHD nanoparticles, which exhibited significantly teal aggregation-induced emission (AIE) fluorescence to serve as donors. By loading eosin Y (ESY) and sulforhodamine 101 (SR101) acceptors, two artificial LHSs of WP5-NHD-ESY and WP5-NHD-SR101 were constructed by Förster resonance energy transfer (FRET) process, whose energy transfer efficiency and antenna effect were 53.8%, 15.0 and 59.7%, 21.9, respectively. Notably, through the energy transfer in WP5-NHD-SR101, UV region solar energy was efficiently absorbed by WP5-NHD and transferred to SR101 for enhancing ¹O₂ production. In order to mimic natural LHS's photocatalytic utilization, WP5-NHD-SR101 LHS was used as a clean-green oxidant to catalyze the photooxidation of 4-(methylthio)toluene to 4-(methylsulfinyl)toluene, whose yield was significantly improved to 62%, showing potential in solar energy transfer and utilization.