Cyanobiphenyl-spiropyrane and -hemicyanine conjugates for cyanide detection in organic/aqueous media through reverse ICT direction: Their practical applications

Cyanide is one of the most known toxic substances. It is used in many industries and threats human health and environment through releasing with wastewater. Therefore, it is very important to detect its accurate amount, rapidly. Herein, turn-on and turn-off fluorescence sensors of hybrid cyanobiphenyl-spiropyrane and -hemicyanine were developed for the detection of CN− ions on the basis of nuchleophilic addition to indolium moiety. Detection behavior of the both probes toward a series of anions was investigated by means of fluorescence, UV–vis, NMR and TOF-MS techniques. The results obviously indicate that both probes show remarkable spectral changes and high selectivity toward CN− with respect to other tested anions. Cyanide levels in water samples up to 0.208 μM could be quantitatively detected as practical application. A smartphone imaging application was successfully constructed for CN− detection. Noticeably, production of cotton kids and PSF capsules revealed that the probe could be conveniently used for on-site measurement of cyanide without complicated instruments.