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

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. CP1exhibits 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. CP1displays 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 × 10−5and 2.94 × 10−6M, 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 CP1, respectively.