An “AIE+ESIPT” characteristic fluorescent probe for relay recognition of Cu2+ and H2S and its application in food samples and cell imaging

A simple fluorescent probe (TPE-1) based on the combination of tetraphenylethene (TPE) and 2-(2′-hydroxyphenyl)benzothiazole (HBT) was synthesized. TPE-1 possesses both aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) characteristics. The TPE-1 aggregates exhibited rapid (10 s) and highly selective recognition of Cu2+ in THF/H2O (1:9, v/v, HEPES 20 mM, pH = 7.4) solution, and was induced an “on-off” change in the fluorescence. TPE-1-Cu2+ complexes generated in situ can also be used as sensing ensembles for highly selective detection of H2S by Cu2+ displacement. As a result, the fluorescence of TPE-1 was recovered again, and an “on-off-on” fluorescence variation was used to relay Cu2+ and H2S recognition. The detection limits of the probes for Cu2+ and H2S are 9.91 × 10−8 M and 3.80 × 10−7 M, respectively. In addition, the probes can be applied to detect Cu2+ and H2S in some food samples and can also be applied to cell imaging experiments.