Ultrastrong room-temperature phosphorescence in cucurbit[8]uril-mediated crystalline supramolecules for ratiometric detection of phenethylamine
摘要
It is a great challenge to modulate purely organic fluorescence-phosphorescence dual emission in aqueous solution because the excited singlet and triplet states are in competition with each other. Herein, we report a crystalline 1:2 host-guest formed by self-assembly of 4-(4-bromophenyl)-pyridinium derivatives and cucurbit[8]uril, in which a rigid environment rich in weak interactions is directly demonstrated. Due to the inhibition of non-radiative transition and stabilization of triplet exciton in the crystalline environment, the crystalline inclusion complex exhibits ultralong room-temperature phosphorescence lifetime of 3.21 ms with an room-temperature phosphorescence (RTP) quantum yield up to 16.29%. Interestingly, the crystalline 1:2 host-guest complex demonstrates the ability of rapid identification and sensitive fluorescence-phosphorescence ratiometric detection behavior toward phenethylamine, a drug analogue, with a limit of detection as low as 27.5 nM. We believe that this study will undoubtedly broaden the utilizing scopes of RTP and offer a novel avenue for psychoactive substances monitoring.