Synthesis and photophysical investigation of Schiff base as a Mg and Zn fluorescent chemosensor and its application.

In view of the fluorescent switching properties and anti-fatigue properties of diarylethene, a diarylethene fluorescent chemosensor for the immediate detection of zinc ion (Zn ) and magnesium ion (Mg ) in acetonitrile was synthesized in this article. The structure of 1o was determined by performing spectroscopy and elemental analysis. The presence of Zn or Mg made the chemosensor 1o show an obvious "turn-on" fluorescent signal (bright yellow-green for Mg and bright cyan for Zn ). The fluorescent change caused by the 1:1 binding of 1o and Zn or Mg might be due to hindering the excited-state intramolecular proton transfer (ESIPT) process, which were bolstered by Benesi-Hildebrand analysis, Job's plot curves, proton nuclear magnetic resonance ( H-NMR) titration and mass spectrometry. The limits of detection were acquired from the standard curve plots for Mg at 44.6 nM and for Zn at 14 nM. Based on the fluorescent behaviors, a logic gate was constructed with the emission intensity at 528/518 nm as output signal, the ultraviolet-visible (UV-vis) lights, Mg /Zn and EDTA as input signals. Exogenous Zn and Mg fluorescent bioimaging were performed on Hela cells with 1o, indicating its potential application in biodiagnostic analysis. In particular, 1o was manufactured into test paper, and Zn or Mg can be conveniently, efficiently and qualitatively identified by the fluorescent color variation of the test strips.