Selective fluorescence sensing of cyanide with an o-(carboxamido)trifluoroacetophenone fused with a cyano-1,2-diphenylethylene fluorophore

A novel fluorescence probe has been synthesized, which consists of o-(carboxamido)trifluoroacetophenone moiety as the recognition element and cyano-1,2-diphenylethylene moiety as the signaling unit. Fluorescence titrations of the probe with anions such as F−, Cl−, I−, CN−, SCN−, AcO−, H2PO4-, HSO4-, and ClO4- as their Bu4N+ salts in acetonitrile show that CN− is the most efficient quencher, AcO− and F− follow it, and other anions show little changes. In an aqueous medium, MeOH-water (9:1), the probe shows fluorescence quenching only toward cyanide and no changes toward the other anions.

A fluorescence probe based on an o-(carboxamido)trifluoroacetophenone binding motif shows selective fluorescence quenching toward cyanide among various anions examined. In particular, the probe responds only to cyanide in aqueous media.