Highly selective detection of cyanide by 2-hydroxyphenylsalicylimine of latent fluorescence through the cyanide-catalyzed imine-to-oxazole transformation

We report a fluorogenic probe (1) of latent fluorescence based on 2-hydroxyphenylsalicylimine for selective detection of cyanide. The probe has shown a highly selective and sensitive response to cyanide over other various anions with a micromolar limit of detection (LOD = 9.4 μM) in aqueous DMSO solvent. When CN− was added to 1, the probe exhibited a strong blue fluorescence through the cyanide-catalyzed imine-to-oxazole transformation, which was easily detectable under a portable UV spectroscope.