Synthesis And Application Of Multicarboxylate Ligands Containing Isophthalic Acid Unit

Metal-organic frameworks，which are formed by the self-assembly of metal ionsand organic ligands, have emerged as a new type of porous materials with unique andoutstanding properties, including high surface area, high porosity, easily tunable poresize and function. These attributes make them great potential applications in the areasof gas storage, separation and catalysis.In this thesis, the characteristic, classification, design and synthesis of MOFs aswell as their applicaitons in the fields of gas storage, separation and catalysis werereviewed. Three ploycarboxylate ligands containing isophthalic acid units have beensynthesized. And three three-dimensional MOFs have been synthesized based uponthese ploycarboxylate ligands. The physicochemical properties and adsorptionbehaviors of these MOFs have also been characterized. The main results obtained inthis thesis are as follows:（1） Three ploycarboxylic ligands,1,3-bis[3,5-（dicarboxylate）phenoxy]-2-hydr-oxy-propane （H4L1）,1,3-bis[3,5-（dicarboxylate）phenoxy]-2-carbonylpropane （H4L2）,2,4,6-tris（3,5-dicarboxylphenylamino）-1,3,5-triazine （H₆L3）, have been preparedaccording to the literatures. The molecular structures of the three ligands werecharacterized by means of Fourier transform infrared spectroscopy （FT-IR） and theproton nuclear magnetic resonance spectra （1H-NMR）.（2） By using hydrothermal method, a cobalt complex, namely,[Co₂(C₁₉H₁₂O₁₁)(C₁₀H₈N₂)2]n,1, was synthesized based on flexible H4L1and rigid4,4’-bipyridine. H4L2coordination with zinc（II） gave a three dimensional MOF,namely,[Zn2(C₁₉H₁₂O₁₁)（C₄H₉NO）2]·C₄H₉NO,2. And the two compounds werecharacterized by infra-red spectrum （IR）, UV-Vis spectrum, thermo-gravimetricanalysis （TGA）, single crystal X-ray diffraction, powder X-ray diffraction. In complex1, two six-coordinated cobalt atoms were connected by two bidentate carboxylicgroups, forming an octahedral dimetallic cluster, which can be considered as asix-connected node to connect four L ligand molecules and two other dimetallicclusters. The flexible tetracarboxylate ligand L can be considered as a tetrahedral4-connected node to connect four dimetallic clusters. Thus, the framework of1features a sqc422net. Both1and2are not reported in the literature.（3） A rht-type topological MOFs, complex3, have been prepared based uponligand H₆L3and Cu（NO3）2using solvothermal method. The physicochemical properties of complexe3were characterized by means of the techniques, such asFT-IR, powder X-ray diffraction （PXRD）, thermal gravimetric analysis （TGA） andLow-temperature N2adsorption and desorption curve. The adsorption properties ofcomplex3for phenol in aqueous solution were studied in detail. It was found that theadsorption amounts increased with the contact times, which reached equilibrium afterabout5h. When the adsorbent amount was certain, the equilibrium adsorptionamounts increased with the initial concentration of phenol increased; on the otherhand, the adsorption capacity decreased with the increase of temperature. Theframeworks of MOF samples adsorbed phenol remain stable, and the MOF samplescould be regenerated easily by being treated with methanol.