Noncovalent Bridged Bis(Coumarin-24-Crown-8) Phosphorescent Supramolecular Switch

摘要

A multicolor room temperature phosphorescence (RTP) supramolecularphoto-switch encryption film is constructed by the coassembly of coumarin-24-crown-8 (C24C8), diarylethene dicationic alkylammonium derivative (1),rhodamine B (RhB) and poly(vinyl alcohol) (PVA). Benefiting from the tightlybinding of C24C8 and secondary alkylammonium ion, 1 formed noncovalentbridged bis(coumarin-24-crown-8), which displayed photo-switchable RTPwith green afterglow (more than 5 s) after coassembly with PVA. Especiallydoping with RhB gave a photo-switchable highly efficient phosphorescenceharvestingsystem with multicolor through triplet-to-singlet F?rster-resonanceenergy transfer (TS-FRET). The energy transfer efficiency and antenna effectof C24C8+RhB@PVA film reached 88.3 and 62.6 when the donor/acceptorratio is 50:1, respectively. Therefore, diarylethene noncovalent bridgedbis(coumarin-24-crown-8) supramolecular assembly not only displays a multicolorphotoluminescence-switch, but also presents a phosphorescent photoswitchwith afterglow, which provides a simple and feasible way to constructsmart RTP materials through host-guest strategy.