A new metal-organic framework (MOF) {[Cd(L)_0.5(4, 4'-bpy)_0.5]·H₂O}_n (1), where H₄L=(1, 1': 4', 1″-terphenyl)-2, 2″, 4, 4″-tetracarboxylic acid, 4, 4'-bpy=4, 4'-bipyridine, was synthesized by hydro-solvothermal method. The structure of complex 1 was characterized by single-crystal X-ray diffraction, elemental analysis, powder X-ray diffraction, thermogravimetric analysis, and infrared spectrum analysis. The analysis of single crystal structure shows that 1 is a 3D structure, belonging to the monoclinic crystal system, C2/c space group. Cd(Ⅱ) connects L^4- and 4, 4'-bpy to form a 2D plane structure, and the layers are connected by L^4- to form a 3D network structure. The MOF shows good stability and can be used for the detection of tetracycline (TET) and p-nitrophenol (4-NP) by fluorescence quenching. The detection limits of TET and 4-NP were 0.15 and 0.062 μmol·L^-1, respectively. In addition, the fluorescence quenching mechanism of 1 was also studied. 1 can be successfully applied to the determination of TET and 4-NP content in Yanhe water samples.

Three coordination polymers [Mn(epda)(2,2′-bipy)(H₂O)] (1), [Mn(epda)(phen)] (2), and [Co₂(epda)₂(bpe)₂(H₂O)₄]·5H₂O (3) (H₂epda=5-ethyl-pyridine-2,3-dicarboxylic acid, 2,2′-bipy=2,2′-bipyridine, phen=phenanthroline, bpe=1,2-bis(4-pyridyl) ethylene) were synthesized by solvothermal reactions and characterized by single-crystal X-ray diffraction, thermogravimetric analyses, IR spectroscopy and elemental analysis. 1 displays a 1D chain structure, and these chains are joined by O—H…O hydrogen bonding and π-π stacking interactions to generate a 2D layer structure. 2 displays a 2D layer structure, and adjacent layers are generated 3D architecture through π-π stacking interactions. 3 displays a 1D chain structure, and adjacent chains are generated double layer structure through O—H…O hydrogen bonding. The fluorescent properties of 1 and 3 indicate that they can potentially be used as a luminescent sensor. 1 was highly selective and sensitive towards o-nitrophenol through different detection mechanisms, however, 3 was highly selective and sensitive towards 2,4,6-trinitrophenol. In addition, the magnetic behavior of 2 has also been investigated.

A novel coordination polymer (CP) {[Cd₂(L)(1,4-bimb)_1.5(DMF)₂]·DMF}_n (1) (H₄L=5, 5′-[1,1′-biphenyl-4,4′-diylbis(oxy)]diisophthalic acid, 1,4-bimb=1,4-bis(imidazole-1-ylmethyl)-benzene) has been designed and synthesized through solvothermal reaction. Structural analysis shows that Cd(Ⅱ) is connected by H₄L and 1,4-bimb to form a 2D network, and 1,4-bimb further expands the 2D network into a 3D framework. CP 1 can be used as an excellent fluorescence sensor for Fe³⁺ and 4-nitrophenol (4-NP), with low detection limits and good anti-interference. The detection limits of Fe³⁺ and 4-NP were 0.034 and 0.031 μmol·L^-1, respectively. In addition, the fluorescence quenching mechanism was studied. 1 was successfully applied to determine Fe³⁺ and 4-NP content in the Yanhe River water sample.