Anion-binding-induced and reduced fluorescence emission (ABIFE & ABRFE): A fluorescent chemo sensor for selective turn-on/off detection of cyanide and fluoride.

A new hydrazine based π-hole assisted, electron deficient turn-on/off fluorescent and colorimetric sensor L with anion-binding induced/reduced fluorescent emission (ABIFE & ABRFE) has been designed and synthesized. The prepared sensor L exhibited excellent turn-on fluorescence emission in the presence of cyanide ion through ABIFE. On the other hand, the receptor L turns-off its fluorescence intensity upon binding with fluoride; however, the reduced emission intensity of this complex of L is recovered by addition of cyanide.