Humidity- and Temperature-Tunable Multicolor Luminescence of Cucurbit[8]uril-Based Supramolecular Assembly

Fabrication of tunable luminescent materials by a single luminophore is a challenge owning to the limit of emissive properties of monofluorophores. Herein, a type of temperature and humidity dual-responsive luminescent material based on host–guest supramolecular self-assembly was developed. Included into the cavity of cucurbit[8]uril (CB[8]) to form a 1:2 host–guest binding motif, the highly blue-emissive thiazolothiazole methyl-viologen (TMV) molecules were promoted to stack closely with a sharp luminescence decrease at 460 nm and rise of the dimer emission at 535 nm, especially at high concentrations in aqueous solution, which was demonstrated by fluorescence spectra, UV–vis absorbance spectra, NMR, and ITC data. Accordingly, when printed on paper, the 1/2 CB[8]/TMV complex presented a reversibly humidity-dependent emissive behavior with luminescent color changing from greenish-yellow in wet to blue upon evaporation. Besides, the  sensitivity of the host–guest interaction endowed the CB[8]/TMV complexes...