3D cadmium(II)‐based coordination polymer constructed from V‐shaped semirigid ligand: Selective detection of oxoanion pollutants CrO${}_4$${}^{2-}$, Cr${}_2$O${}_7$${}^{2-}$, MnO${}_4$${}^{-}$ in water

A new coordination polymer (CP), namely, [Cd(HL)(4,4′‐bipy)] (1) (H${}_3$L = 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 (6${}^3$)(6${}^9$·8) topology. Meanwhile, it shows high selectivity and sensitivity for oxoanion pollutants CrO${}_4$${}^{2-}$, Cr${}_2$O${}_7$${}^{2-}$, and MnO${}_4$${}^{-}$ anions in aqueous solutions with detection limits of 4.12 × 10${}^{-6}$ M, 1.75 × 10${}^{-6}$ M, and 6.47 × 10${}^{-7}$ M, respectively. The high selectivity and low detection limit indicate that the compound is promising functional luminescence probe for CrO${}_4$${}^{2-}$, Cr${}_2$O${}_7$${}^{2-}$, and MnO${}_4$${}^{-}$. The mechanisms of the quenching effect and sensing properties were discussed in detail. (© 2019 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)