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The detection of antibiotics is still the focus of global attention, because their abuse can lead to biological hazards. Herein, three new coordination polymers as fluorescent sensors, namely [Cd3(L1)(MTC)2(H2O)6] (CP 1), [Zn(L1)(HMTC)·2H2O] (CP 2) and [Cd3(L2)(MTC)2(H2O)6] (CP 3) [H3MTC = trimellitic acid, L1 = (E)-4,4′-(ethene-l,2-diyl)bis(N-pyridin-3-yl)benzamide) and L2 = (E)-4,4′-(diazene-1,2-diyl)bis(N-(pyridin-3-yl)benzamide)], were synthesized by using two bis(pyridyl)-bis(amide) ligands with different spacers and trimellitic acid mixed ligands under hydrothermal conditions, which were structurally characterized by single crystal X-ray diffraction, PXRD and IR. CP 1 and CP 3 have similar 2D coordination networks and 3D supramolecular structures, while CP 2 is a 2D coordination structure formed by alternatively linking 1D chains of Zn-L1 and Zn-HMTC, which is further extended to a 3D supramolecular framework. In addition, CPs 1–3 can highly efficiently detect two classes of antibiotics, chlortetracycline and furaltadone, with low LODs, excellent anti-interference ability, pH stability and recyclability. In CPs 1–3, CP 1 has the lowest LOD (5.12 × 10−8 M for CTC and 9.41 × 10−8 M for FTD). The sensing mechanisms, and the influences of composition and structure differences on the performances are discussed. The results provide a reasonable experimental reference for designing CPs and understanding the influencing factors of fluorescence performances. [ABSTRACT FROM AUTHOR]

3-Nitrotyrosine (3-NT), an oxidative stress biomarker, is closely associated with various diseases. Thus, rapid and sensitive detection of 3-NT is of great significance for preventing and treating diseases. Herein, we reported a new 3D zinc-based metal–organic framework (Zn-MOF) [Zn(L)(HBTC)] (L = (E)-4,4′-(ethene-1,2-diyl)bis[(N-pyridin-3-yl)benzamide], H3BTC = 1,3,5-benzenetricarboxylic acid), which was structurally characterized by single crystal X-ray diffraction, IR, PXRD and TG. The Zn-MOF can be used as a highly efficient fluorescence sensing material to provide a direct and low-cost method for the rapid detection of 3-NT and shows high sensitivity with a KSV value of 6.596 × 104 M−1, a rapid luminescence response within 24 s, excellent selectivity, high anti-interference ability and good recyclability. It is the first example of a MOF being used to directly detect 3-NT as a luminescence sensor to our knowledge. The sensing mechanism of the Zn-MOF towards 3-NT is discussed in detail, which provides a basis for the rational design of MOF sensing materials and their application in biomarker detection. [ABSTRACT FROM AUTHOR]

Two new CdII/ZnII coordination polymers using the bis(pyridyl)-bis(amide) ligand as the main ligand and 1,2,4,5-benzenetetracarboxylic acid (H 4 BTEC) as the auxiliary ligand were designed and synthesized, which can sensitively detect biomarker 3-nitrotyrosine as fluorescence sensors. They have the advantages of excellent stability, anti-interference, recyclability and low limits of detection. [Display omitted] 3-Nitrotyrosine (3-NT), as a stable biomarker in the human body, is closely related to a variety of diseases. Therefore, the detection of 3-NT is of important significance for human disease monitoring. In addition, under the same dimension, the influence of CPs with different metals on 3-NT detection still has important research value. Herein, we successfully synthesized two new 2D coordination polymers (CPs), namely [M(L)(BTEC) 0.5 ]·H 2 O (M = Cd for CP 1 , M = Zn for CP 2), by using the bis(pyridyl)-bis(amide) ligand L [(E)-4,4′-(ethene-1,2-diyl)bis[(N -pyridin-3-yl)benzamide] as the main ligand and 1,2,4,5-benzenetetracarboxylic acid (H 4 BTEC) as the auxiliary ligand under hydrothermal conditions. CPs 1 – 2 can be used as fluorescent sensors to effectively detect 3-NT, and have the advantages of excellent stability, anti-interference, recyclability and low limits of detection (LODs). The influence of the different metals in the CPs on the fluorescence sensing 3-NT was discussed, and the difference of sensing mechanism and performance of CPs 1 – 2 on 3-NT were studied in detail, which provided a reference for the design of CPs and the influencing factors of 3-NT detection. [ABSTRACT FROM AUTHOR]

The metal-organic framework {[Zn2(CAM)(μ2-OH)(bpp)] ·2H2O} n ( 1) [H3CAM = 4-hydroxypyridine-2,6-dicarboxylic acid, bpp = 1,3-bis(4-pyridyl)propane], was hydrothermally synthesized and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. Compound 1 presents a three dimensional self-penetrating 8-connected framework with the Schläfli symbol 420.53.65. In addition, the fluorescent properties and thermal stability of 1 were discussed as well. [ABSTRACT FROM AUTHOR]