A fluorescent Zinc(II)-based layered complex for selective sensing of Cr2O72– and Fe3+ ions in water system

Abstract

A new Zn(II)-organic framework with 2,2-bipyridine-5,5-dicarboxylate (bpydc) ligand {[Zn(H₂O)(bpydc)]·CH₃OH}_n was solvothermally obtained, and structurally and photophysically characterized. Structural analysis reveals that the distorted Zn^II octahedra are periodically extended by the ditopic bpydc^2‒ connector, leading to a coplanar grid-like (4 4) layer. The complex has excellent thermal and environmental stability as well as good dispersion in water system. More interestingly, resulting from the efficient ligand to metal charge transfer, the complex can emit strong blue emission dispersed in water medium and can detect both Cr₂O₇^2– and Fe³⁺ ions through fluorescence quenching with high quench constants (1.12×10⁵ M^-1 and 2.12×10⁴ M^-1) and low limits of detection (0.54 mM and 1.02 mM). These interesting results suggest that the complex can be potentially served as a promising dual-responsive luminescent sensor material for environmental pollutant monitoring.