A highly selective, sensitive and reversible fluorescence chemosensor for Zn2+ and its cell viability

A new imine conjugate Schiff base ligand (H2L) was prepared and evaluated for its sensing properties. H2L detects Zn2+ selectively among the wide range of metal ions. The sensing behavior of H2L was identified by UV-vis, fluorescence and H-1 NMR titration. H2L shows fluorescence switch ON with the Zn2+ ion among 18 other metal/heavy metal ions with a detection limit of 1.47 mu M. The binding of Zn2+ was confirmed by single crystal X-ray studies, which reveal the formation of binuclear complex (1). The packing diagram of H2L reveals the presence of rare linear C-H center dot center dot center dot C interactions (bond distance 2.79 and bond angle 180 degrees) which form 1D-polymeric chains. Furthermore, the cytotoxicity of H2L and 1 has been assessed against MCF-7 and A375 cell lines and both are found to have marginal toxicity.