Artificial light-harvesting supramolecular assemblies with controllable fluorescence intensity formed by cyclodextrin-based host-gost complexation

Abstract In the present work, we have designed and synthesized an amphiphilic hydroxyflavone derivative (HFD) with a hydrophilic side chain, which can self-assembly into spherical aggregates with the diameter at about 100 nm in aqueous solution. Meanwhile, HFD can interact with cyclodextrins (CDs) with different cavity sizes through host-guest interaction, which also exhibited different fluorescence intensity in aqueous solution. α-CD has no obvious effect on the fluorescence and self-assembled structures because the cavity of α-CD is too small to encapsulate HFD into its cavity. However, β-CD and γ-CD can form 1: 1 and 1: 2 complexes with HFD in aqueous solution, which lead to enhanced and reduced fluorescence intensity of HFD, respectively. Moreover, after addition of β-CD and γ-CD, HFD can self-assembly into aggregated nanoparticles and spherical aggregates with the diameter at about 200 nm, respectively. More interestingly, artificial light-harvesting systems can be constructed by using HFD and HFD with CDs as energy donors with gradual addition of sulfo-cyanine5 carboxylic acid (Cy5) as energy acceptors in aqueous solution.