An efficient colorimetric probe for fluoride ion based on schiff base

A novel colorimetric probe 2-hydroxy-1-naphthylaldehyde-2-quinoline acylhydra-zone (L) was synthesized and its structure was characterized by FT-IR, H-1 NMR, C-13 NMR and HRMS method. The sensing ability of the probe towards anions (F , Cl , Br , I , NO3, AcO , HSO4, H2PO4 , ClO4) was determined by colorimetric, UV-vis and NMR studies. The results showed that L had an efficient colorimetric sensing ability for fluoride ion by changing color from colorless to yellow. The probe L bound to F in a 1:2 stoichiometric manner. Furthermore, the binding constant of the complex was 1.37 x 10(9) M (2) with the detection limit of 8.28 x 10 (6) M. The recognition mechanism was attributed to the intermolecular proton transfer between the hydroxyl group of the probe L and the fluoride according to H-1 NMR titration method. (C) 2018 Elsevier B.V. All rights reserved.