Chemosensor for fluoride ion based on chromone

Abstract

Abstract A novel visual chemosensor; receptor R, with high selectivity for fluoride ion based on chromone has been synthesized by simple condensation reaction between 3-formylchromone and 2,4-dinitrophenylhydrazine hydrochloride. The receptor R shows a dramatic color change from yellow to intense red upon the addition of fluoride ion with a large red shift of 118 nm in acetonitrile. No significant color change was observed upon the addition of other anions such as Cl − , Br − , I − , NO 3 − , HSO 4 − , H 2 PO 4 − and AcO − . Job's plot and Benesi–Hildebrand equation indicate that R associates with F − in a 1:1 stoichiometry. Investigation of 1 H NMR spectrum titration indicates that creates a hydrogen bonding interaction between F − and R. The receptor R proved to be an efficient naked eye detector for fluoride ion.