First fluorescence sensor for hydrazine ion: An effective “turn-on” detection based on thiophene-cyanodistyrene Schiff-base

Abstract

Hydrazine and its cation were important but hazardous reagents. Although the fluorescence sensor for hydrazine had been widely reported, the fluorescence sensor for hydrazine ion was not presented so far. In this work, the first fluorescence sensor for hydrazine ion was prepared based on the effective “turn-on” fluorescence of thiophene-cyanodistyrene Schiff-base (TCS). TCS was synthesized in simple condensation with high yield. It exhibited weak fluorescence at 450–550 nm in aqueous media due to the strong PET effect suppressing AIE effect. It displayed excellent selective sensing ability for Hg2+ and N2H62+ with strong “turn-on” fluorescence based on the disruption of PET effect. The fluorescence response to Hg2+ was masked by Cl−, achieving the high selective detection for N2H62+ only. The detection limit for N2H62+ was 1.05 × 10−7 M. The 2:1 stoichiometric ratio and the sensing mechanism were confirmed by the Job’s plot, MS spectrum, 1H NMR spectrum, FT-IR spectrum and theory calculation. The detecting experiments for N2H62+ in tap water and water of Minjiang River implied the good application potential for sensing N2H62+ in real water environments.