Abstract
| - A chiral pyran derivative containing two cholesteryl groups (1) is synthesized, and its optical properties areinvestigated. Whereas the isolated molecule of 1 is virtually nonluminescent in dilute solutions, it becomeshighly emissive with a 2 orders of magnitude increase in fluorescence quantum yield upon aggregation inpoor solvents or in solid state, showing a novel phenomenon of aggregation-induced emission (AIE). Thecolor and efficiency of the AIE of 1 can be tuned by varying the morphology of its aggregates: photoluminescence of its aggregates formed in a tetrahydrofuran/water mixture progressively red-shifts (green→ yellow → red) with increasing water content of the mixture, with the crystalline aggregates emitting bluerlights in higher efficiencies than their amorphous counterparts.
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