Novel indole based colorimetric and “turn on” fluorescent sensors for biologically important fluoride anion sensing

A novel indole Hydrazone receptor 1 has been synthesized by one step of condensation, which can act as an efficient colorimetric and “turn on” fluorescent sensor for fluoride anions; Benesi–Hildebrand equation indicates that 1 associates with F− in a 1:1 stoichiometry; [TBA]OH and 1H NMR titration experiments indicate that the deprotonation process involved upon addition of fluoride anions.