A Zn(II) Coordination Polymer for Fluorescent Turn-Off Selective Sensing of Heavy Metal Cation and Toxic Inorganic Anions

Abstract

A novel coordination polymer [Zn(atyha)2]n (1) (Hatyha = 2-(2-aminothiazole-4-yl)-2- hydroxyiminoacetic acid) was constructed by hydrothermal reaction of Zn2+ with Hatyha ligand. CP 1 exhibits a 2D (4,4)-connected topological framework with Schläfli symbol of {44·62}, where atyha− anions serve as tridentate ligands, bridging with Zn2+ through carboxylate, thiazole and oxime groups. CP 1 displays a strong ligand-based photoluminescence at 390 nm in the solid state, and remains significantly structurally stable in water. Interestingly, it can be utilized as a fluorescent probe for selective and sensitive sensing of Fe3+, Cr2O72− and MnO4− through the fluorescent turn-off effect with limit of detection (LOD) of 3.66 × 10−6, 2.38 × 10−5 and 2.94 × 10−6 M, respectively. Moreover, the efficient recyclability for detection of Fe3+ and Cr2O72− is better than that for MnO4−. The mechanisms of fluorescent quenching involve reversible overlap of UV-Vis absorption bands of the analytes (Fe3+, Cr2O72− and MnO4−) with fluorescence excitation and emission bands for CP 1, respectively.