Two Stable Zn (II) Coordination Polymers as Dual‐Functional Luminescent Sensors for Efficient Detection of Nitrofurazone, Pefloxacin, and Cr₂O₇²⁻ in Water

Abstract

Two new Zn (II) coordination polymers, {[Zn (OBA)(L)]·H2O}n (1) and {[Zn2(TCPA)2(L)2]·H2O}n (2), were synthesized under hydrothermal condition. Here, L = 2‐(1H‐imidazol‐1‐yl)methyl)‐5,6‐dimethyl‐1H‐benzo[d]imidazole, H2OBA = 4,4′‐dicarboxydiphenyl ether, H2TCPA = tetrachloroterephthalic acid. Structural analyses revealed that 1 exhibits a 2D hcb topology of {63} while 2 displays a four‐connected 2D sql layer with the point symbol of {44.62}. Both 1 and 2 are extended to 3D supramolecular frameworks through hydrogen bonding interactions. These CPs demonstrate remarkable thermal and chemical stability across a wide pH range of 3 to 12. Notably, they can serve as dual‐functional luminescent sensors for the sensitive, selective, and recyclable detection of nitrofurazone (NFZ)/Cr2O72− ions (for 1) and pefloxacin (PEF)/Cr2O72− ions (for 2) in aqueous solutions. The limits of detection (LODs) of 1 towards NFZ and Cr2O72− ions are 2.20 × 10−7 and 4.90 × 10−7 mol·L−1, respectively. For 2, the LOD is 5.42 × 10−8 mol·L−1 for PEF and 3.40 × 10−7 mol·L−1 for Cr2O72− ions. It is worth noting that this is the first report of luminescent Zn (II)‐CPs based on L ligands for the sensing of NFZ, PEF, and Cr2O72− ions. And the quenching mechanism was deeply investigated.