A NIR sensor for cyanide detection and its application in cell imaging.

A novel 'D-π-A' sensor 1 has been designed and prepared via the condensation reaction of 3‑ethyl‑2‑methyl‑1,3‑benzothiazol‑3‑ium iodide and 5‑nitro‑o‑vanillin. Upon treatment with cyanide, sensor 1 exhibited a significant near-infrared (NIR) fluorescence quenching at 663nm. The MS, IR, 1H NMR and DFT methods confirmed that the response of 1 to cyanide is due to the nucleophilic addition reaction, which results in the inhibition of the Intramolecular Charge Transfer (ICT) process in the sensor. Furthermore, sensor 1 was used for the determination of CN- in HeLa cells.