3D Cadmium(II)‐Based Coordination Polymer Constructed from V‐Shaped Semirigid Ligand: Selective Detection of Oxoanion Pollutants CrO42–, Cr2O72–, MnO4– in Water

A new coordination polymer (CP), namely, Cd(HL)(4,4′‐bipy)] ( 1 ) (H₃L = 4‐(5‐carboxy‐pyridine‐3‐yloxy)‐phthalic acid, 4,4′‐bipy = 4,4′‐bipyridine), was synthesized employing a V‐shaped asymmetric tricarboxylic acid ligand under hydrothermal condition. Single‐crystal X‐ray diffraction analysis indicates that compound 1 exhibits a novel three‐dimensional (3D) framework with (3, 5)‐connected (6³)(6⁹ · 8) topology. Meanwhile, it shows high selectivity and sensitivity for oxoanion pollutants CrO₄^2–, Cr₂O₇^2–, and MnO₄^– anions in aqueous solutions with detection limits of 4.12 × 10^–6 M, 1.75 × 10^–6 M, and 6.47 × 10^–7 M, respectively. The high selectivity and low detection limit indicate that the compound is promising functional luminescence probe for CrO₄^2–, Cr₂O₇^2–, and MnO₄^–. The mechanisms of the quenching effect and sensing properties were discussed in detail.