Chemosensor for fluoride ion based on chromone

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-, NO3-, HSO4-, H2PO4- and AcO-. Job's plot and Benesi-Hildebrand equation indicate that R associates with F- in a 1:1 stoichiometry. Investigation of H-1 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. (C) 2015 Elsevier B.V. All rights reserved.