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

Abstract

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 ¹H 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 μM. 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⋯C interactions (bond distance 2.79 Å and bond angle 180°) 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.