Highly selective sensing of cyanide by a benzochromene-based ratiometric fluorescence probe

Enone-functionalized benzochromene chemodosimeter (1) was prepared through the Baylis–Hillman condensation reaction and was utilized as a ratiometric fluorescence probe for cyanide anions in aqueous buffer. The probe has shown a selective and sensitive response to cyanides over other various anions through the Michael addition and a subsequent [1,3]-sigmatropic rearrangement reaction. When cyanide anions were added, a prominent ratiometric fluorescence change of 1 was observed thus allowing to detect the micromolar concentration of cyanides by the naked eye.