Three-Step Energy-Funneling Supramolecular Light-Harvesting System for Enhanced Superoxide Radical Anion-Mediated Photocatalytic Oxidation

Abstract Inspired by the sequential energy-transfer process in natural photosynthesis, we report an aqueous artificial three-step light-harvesting system (LHS) based on a tadpole-shaped amphiphile (PCSA). PCSA, comprising a pyrene-based cyanostyrene hydrophobic segment and a quaternary ammonium hydrophilic headgroup, readily self-assembles into supramolecular nanofibers in water and serves as an efficient energy donor. Sequential incorporation of Rhodamine B (RhB), Sulforhodamine 101 (SR101), and Cyanine 5 (Cy5) establishes a cascade Förster resonance energy transfer (FRET) pathway, enabling efficient excitation energy funneling and markedly enhanced generation of superoxide radical anions (O2•–) via a predominantly Type I photochemical process. Benefiting from the amplified photoreactivity, the multistep LHS efficiently catalyzes the aerobic oxidation of arylboronic acids to phenols in up to 96% yield. This work provides a supramolecular strategy for coupling multistep energy funneling with efficient O2•–-mediated photocatalysis in aqueous media.