Two-step sequential energy transfer of molecular assemblies based on host-guest interactions for the construction of photochemically catalyzed artificial light-harvesting systems

Abstract

In the present work, a highly efficient artificial light-harvesting system with a two-step sequential energy transfer process based on host-guest interactions between cyano-substituted p-phenylenevinylene derivative (PPTA) and cucurbit [7]uril (CB [7]) has been constructed in an aqueous media, in which the molecular assemblies was employed as energy donors, two dyes including eosin Y (EY) and sulforhodamine (SR101) were used as energy acceptors. The obtained PPTA-CB [7] supramolecular assemblies have aggregation-induced emission (AIE) effect and can be used as an ideal donor to transfer energy to EY. Then, inspired by the multi-step energy transfer in nature, the PPTA-CB [7]+EY system was chosen as the energy donor while SR101 was selected as the energy acceptor to construct an efficient light-harvesting system with a two-step sequential energy transfer, which demonstrated high FRET efficiencies of 38% and 33% in the two-step process, respectively. The light-harvesting systems also exhibit high antenna efficiencies of 23.7 and 20.1 with a 100:1 donor/acceptor ratio, respectively. More importantly, the PPTA-CB [7]+EY + SR101 system exhibited high activity for the photocatalytic dehalogenation of 2-bromo-1-phenylethanone with a yield of up to 86% in an aqueous solution.