Fluorescence probe with AIE properties for ratiometric/turn off detecting of water in organic solvents and solid state

Abstract

ABSTRACT Efficient detection of trace water was important before use in water-sensitive reactions. Herein, a fluorescence sensor 1,4-bis((E)-(2-(benzo[d]thiazol-2-yl)hydrazineylidene)methyl)benzene (DHB) was designed and synthesised by a simple one-step reaction using 2-hydrazinobenzothiazole and terephthalaldehyde as raw materials. DHB showed aggregation-induced emission characteristics in solid state and 1,4-dioxane/H2O mixture. In addition, the fluorescent colour changes in IPA and fluorescence quenching in N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), dimethyl sulphoxide (DMSO), glycerine (GI), and 1,3-propanediol (1,3-PDO) were obviously observed with increasing water content, making DHB a highly sensitive fluorescent sensor for water detection with a detection limit of 0.174% for IPA, 0.040% for DMSO, 0.067% for DMF, 0.039% for DMA, 0.069% for 1,3-PDO, and 0.013% for GI, respectively. Further, DHB displayed fluorescence colorimetric response to water in solid state. 1H NMR titration indicated that the sensing mechanism for the detection of trace water was form hydrogen bonds between H2O molecule and amino group of DHB.