Simple chloro substituted HBT derivative portraying coupling of AIE and ESIPT phenomenon: Ratiometric detection of S2- and CN- in 100% aqueous medium

A simple hydroxybenzothiazole (HBT) derivative, namely 2-(benzo[d]thiazol-2-yl)-4-chlorophenol (BTCP) was synthesized and its photophysical properties were studied spectroscopically. Detailed steady state and time resolved spectroscopic studies along with Field Emission Scanning Electron Microscope (FESEM) and Dynamic Light Scattering (DLS) analyses established the coupling of Excited State Intramolecular Proton Transfer (ESIPT) and Aggregation Induced Emission (AIE) in BTCP molecule. The current report stands out as AIE and ESIPT coupling observed by introduction of a simple Chlorine atom in an established ESIPT active probe. The utility of BTCP has been demonstrated by successful ratiometric determination of S2- as well as CN- in aqueous medium. Paper strips coated with BTCP could successfully detect the anions by a change in color under UV-light.