Rhodafluor-based chromo- and fluorogenic probe for cyanide anion

A rhodafluor-based chromo- and fluorogenic probe for CN− has been designed, synthesized, and characterized. The probe comprises a spectroscopic unit of rhodafluor and a CN−-specific trifluoroacetylamino binding unit. The probe itself is colorless and nonfluorescent because of its spirocyclic structure, whereas ring-opening of the corresponding spirolactone induced by CN− gives rise to strong fluorescence emission and also clear color changes. In the system, an excellent selectivity toward the detection of CN− in aqueous solution over a wide range of tested anions was observed; moreover, most of the background anions have not any interference with the detection of CN−.