Syntheses And Properties Of Novel Zirconium-based Metal-Organic Frameworks

Metal-Organic Frameworks（MOFs）are crystalline materials with high porosity and homogeneous structure prepared by self-assembly of metal ions or metal clusters as secondary structural units with ligands containing different structures such as nitrogen heterocycles and carboxyl groups.Compared with conventional porous materials,the large amount of transition metals and organic ligands in MOFs can not only achieve effective tuning of the structure and properties of MOFs,but also obtain a larger specific surface area and higher void fraction.It has important research significance in the fields of multiphase catalysis,gas-liquid two-phase adsorption and separation,luminescent materials,electromagnetism,etc.Zirconium-based metal-organic skeletons（Zr-MOFs）are new materials with a wide variety of structures,high stability and excellent properties.In this thesis,four functionalized organic ligands were designed and synthesized,and a series of Zr-MOFs materials were constructed by the solvothermal reaction.Their structure and performance were characterized.And their applications in anion and cation detection,explosive recognition and photocatalysis were mainly investigated.The main studies are as follows.1.Synthesis and properties of novel Zr-based MOFs fluorescent probe materialsIn this part,based on functionalized dicarboxylic ligands,three UiO-type MOFs,UiO-67-L1,UiO-68-L2 and UiO-68-L3 were synthesized and structurally characterized.It was found that all three compounds possess good stability and fluorescence properties,and can be used as highly sensitive and selective fluorescent probes.UiO-67-L1 can be used as a fluorescent probe for the detection of Cr₂O₇^2-and TNP.Its detection limits for Cr₂O₇^2-and TNP were 0.29μM and 31.86 n M.UiO-68-L2can be used as a selective and efficient 2,4-DNP detection sensor with a K_sv value of2.21×10⁴M^-1 and a detection limit of 1.21μM.UiO-68-L3 can can achieve trace detection of Hg²⁺and tetracycline,and its detection of Cr₂O₇^2-and TNP were 2.01μM and 0.44 n M.2.Synthesis and properties of novel Zr-based MOFs photocatalystsIn this part,three Zr-based MOFs were evaluated for their photocatalytic performance in detail.Based on a tetracarboxylic aid,Compund 4[Zr₆O₄（OH）₈（TCBP）₃]·xsolvent with（4,12）-connected ftw topological exhibtis excellent photodegradation to Cr₂O₇^2-and tetracycline in water with efficiency of 94.2%and 81.1%.The photodegradation efficiencies of UiO-67-L1 for Cr₂O₇^2-and tetracycline were 92.2%and 91.7%,and those of UiO-68-L2 for Cr₂O₇^2-and tetracycline were91.2%and 92.9%.All three catalysts have good recoverability.