Rational Design of an ICT-Based Chemodosimeter with Aggregation-Induced Emission for Colorimetric and Ratiometric Fluorescent Detection of Cyanide in a Wide pH Range.

An alkoxy-substituted 1,3-indanedione-based chemodosimeter with an aggregation-induced emission (AIE) characteristic was rationally designed and synthesized for the ultrasensitive and selective sensing of cyanide in a wide pH range of 3.0-12.0. The nucleophilic addition of cyanide to the β-conjugated carbon of the 1,3-indanedione group obstructs intramolecular charge transfer (ICT) and causes a significant change in the absorption and fluorescence spectra, enabling colorimetric and ratiometric fluorescent detection of cyanide in a 90% aqueous solution. The cyanide-sensing mechanism is supported by single-crystal X-ray diffraction analysis, time-dependent density functional theory (TD-DFT) calculations, and H NMR titration experiments. Sensor exhibits strong yellow fluorescence in the solid state due to the AIE effect, and the paper probes containing can be conveniently used to sense cyanide by the naked eye. Furthermore, chemodosimeter was successfully used for sensing cyanide in real environmental water samples.