Azo dyes featuring with nitrobenzoxadiazole (NBD) unit: A new selective chromogenic and fluorogenic sensor for cyanide ion

Three new chemodosimeters 1–3 were prepared, and their chromogenic and fluorogenic behaviors toward various anions were investigated. Receptors 1–3 show exclusive response toward CN− ion and also distinguish CN− from other anions by different color changes in aqueous solution (EtOH/H2O = 3/7, v/v). Among them, receptor 1 selectively exhibits a pronounced CN−-induced fluorescence enhancement. Thus, the receptor 1 can be used as a colorimetric and fluorescent sensor for the determination of CN− ion. The practical use of the receptor 1 for the determination of sodium cyanide (1.5 μM) in aqueous solution was also reported.