A supramolecular cascade assembly with a two-step sequential energy transfer process for enhanced photocatalytic performance

Abstract

It is of great significance to improve the photocatalytic performance of photosensitizers by supramolecular strategies. In this study, we constructed a supramolecular cascade assembly (PATT-CB[7]-SBE-β-CD) comprising an N,N,N′,N′-tetra(p-aminophenyl)-p-phenylenediamine derivative (PATT), cucurbit[7]uril (CB[7]), and sulfobutylether-β-cyclodextrin (SBE-β-CD). Compared to PATT, the supramolecular cascade assembly exhibits a remarkable 30-fold enhancement in fluorescence emission intensity. The excellent fluorescence emission of PATT-CB[7]-SBE-β-CD makes it an optimal energy donor to construct a light-harvesting system (LHS) with Eosin Y (EY) and sulforhodamine 101 (SR101) through a sequential two-step energy transfer process. The PATT-CB[7]-SBE-β-CD+EY+SR101 served as a photosensitizer to facilitate the photocatalytic oxidation of N-phenyltetrahydroisoquinoline and its derivatives. Compared to PATT-CB[7]-SBE-β-CD and PATT-CB[7]-SBE-β-CD+EY, PATT-CB[7]-SBE-β-CD+EY+SR101 exhibits significantly enhanced photocatalytic performance, which is achieved by enhancing the generation efficiency of the superoxide anion radical (O₂˙⁻) through sequential two-step energy transfer processes. The finding of this study demonstrated that the generation of O₂˙⁻ can be greatly enhanced through effective energy transfer to improve the photocatalytic performance.