Preparation, AIE and ESIPT behaviour, controllable solid-state fluorescence and application of Coprobe based on-cyanostilbene.

A simple-cyanostilbene-functioned salicylaldehyde-based Schiff-base probe, which exhibited outstanding 'aggregation-induced emission and excited state intramolecular proton transfer (AIE + ESIPT)' emission in solution, aggregation and solid states, was synthesized in high yield of 87%. Its solid-states with different morphologies emitted different fluorescence after crystallization in EtOH/HO (1/2, v/v) mixtures or pure EtOH solvent. Besides, it exhibited an obvious spectro-photometrical fluorescence quenching for highly selective sensing of Coin THF/water system (ƒ= 60%, pH = 7.4), accompanied by an intense green fluorescence turn-off behavior under UVillumination. The binding stochiometry between the ligand and Cowas found to be 2:1, and the detection limit (DL) was calculated to be 0.41 × 10M. In addition, it could be applied to detect Coin real water samples and on silica gel testing strip.