A α -cyanostilbene-modified Schiff base as efficient turn-on fluorescent chemosensor for Zn 2 +

A novel Schiff base derivative (Z)-3-(4-(hexyloxy)phenyl)-2-(4-((E)-2-hydroxybenzylidene amino)phenyl)acrylonitrile ( L ) was designed, synthesized and characterized. L was used as a Zn 2+ selective, turn-on, fluorescent chemosensor with a detection limit of 0.1 μ M in DMF. 1:1 stoichiometric complex formation of L wih Zn 2+ was confirmed through fluorescent titration experiments and Job’s plot. The enhancement of fluorescence intensity of L with addition of Zn 2+ is the consequence of the inhibited isomerization of the C=N bond, namely chelation-enhanced fluorescence (CHEF) effect. Graphical Abstract α -Cyanostilbene-modified Schiff L was designed as a highly selective and sensitive zinc chemosensor. The complexation of L with Zn 2+ enhanced the fluorescence intensity. This chemosensor could distinguish clearly Zn 2+ from Cd 2+ , a frequently encountered trouble in the design for the Zn 2+ fluorescent probes.