A highly sensitive fluorescent chemosensor for selective detection of zinc (II) ion based on the oxadiazole derivative

A novel fluorescent chemosensor based on the oxadiazole, 2-(2-hydroxyphenyl)-5-(4-methoxyphenyl)-1,3,4-oxadiazole, was designed and synthesized. The interaction of the oxadiazole with different metal ions had been investigated through UV-vis absorption and fluorescence spectra in 9:1 (v/v) ethanol-water (pH = 7.0) solution. The oxadiazole showed a pronounced fluorescence enhancement at 430 nm upon addition of Zn2+ in aqueous solution, whereas it had no apparent interference from other metal ions. The results indicated that the oxadiazole possessed high selectivity and sensitivity to Zn2+ ion. The stoichiometric ratio between the oxadiazole and Zn2+ ion was calculated to be 2:1 by job plot experiment, meanwhile their binding modes was confirmed by H-1 NMR and mass spectrometry. Their association constant was determined to be 1.95 x 10(5) M-1 and the detection limit for Zn2+ ion was 6.14 x 10(-7) mol/L. (C) 2016 Elsevier B.V. All rights reserved.