A selective indole based chemosensor for fluoride ion detection

Abstract

The selective detection of anions via chemosensors have recently emerged as an important area of research due to their vital role in biological, chemical and environmental sciences. An efficient indole based chemosensor C1 exhibiting selective detection of fluoride ions has been synthesized by condensation reaction of substituted indole derived Carbohydrazide 1 with substituted ethenone 2 and characterized by ¹H NMR and ¹³C NMR spectroscopy. Chemosensor shows notable colorimetric changes from light yellow to greenish yellow, upon addition of fluoride ions. The absorption studies shows red shift in the absorption spectra upon titration with fluoride ions. The receptor–anion interaction occurs through hydrogen bonding followed by deprotonation of –OH proton. Chemosensor shows 2:1 stoichiometry as calculated from the Job’s plot.