| Metal-Organic Frameworks (MOFs) or Porous Coordination Polymers (PCPs)are known as a new class of functional porous materials, which have attractedresearch interests of scientists. Numerous works have been reported around this newtopic which started at the beginning of this century. MOFs owe advantages overtraditional porous materials, such as abundant structure topologies, adjustable poresizes (3-100), high surface area (300-6500m2·g-1), chemical composition diversityand structure tailorability. As a new functional material, the application of MOFs ingas adsorption, CO2capture, hydrogen and methane storage, catalysis, drug delivery,single-molecule magnets, molecular recognition, optical and selective separation havegrabbed the attention of society.MOFs are connected by organic ligand and mono-nuclear, bi-nuclear ormulti-nuclear inorganic secondary building units (SBUs). By designing differentorganic ligands with functional groups (such as amino, nitro, fluoro-substituted andsulfonic acid groups, etc.) or choose a different metal centers, MOFs with differentfunctionalities can be achieved. By designing organic ligands with different length,the pore size of MOFs can be controlled. By using Post-Synthesis method, theframework of MOFs materials can be modified by adding functional group toframework or changing the metal center to change the function of MOFs.With the perspective of self-assembly and functional research, we designed threeorganic ligands with pyrimidinyl group, by the method of proportional adjustment, polar modulation, and temperature control,19compounds were obtained undersolvothermal conditions. The structures were analyzed first, then the basiccharacterizations of these compounds were carried out, gas adsorption and separationstudies were performed. The research results of this thesis are as follows:(1) Assembly of ten MOFs (compounds1-10) by the reaction of4-(pyrimidin-5-yl) benzoic acid (4-PmBC) and3-(pyrimidin-5-yl) benzoic (3-PmBC)with transition metals under solvothermal conditions. In compound1, the octa-nuclearcopper cluster is made up of six sulfate ions and eight copper atoms, the framework of1exhibits ant structural topology. There exist one intersecting double-helical chainalong [001] direction and two helices along [110] direction. In the structure ofcompound1, there exist one-dimensional channels with dimensions3.45×4.03along [111] direction, the actived compound1can adsorb hydrogen and carbondioxide and can’t adsorb nitrogen and mathane, so the compound1owns highlyselective CO2adsorption capability over N2and CH4. Compound1exhibits a heat ofsorption (Qst) of47.7KJ·mol-1, which is higher than most of the reported MOFs. Thereare two different SBUs (Cu2N2(CO2)4and Cu2I2N4) in the structure of compound2,and the organic ligands exhibit two different coordination modes,2shows a new(3,4,6)-connected topology. Actived compound2can capture and release I2fleetly.Compound3with dia topology exhibits high thermal stability and can be stable up to350°C. Compounds4and5can be obtained from the same metal and ligand underdifferent solvent conditions, they show different2D structures with same SBUs.Compound6is a2D compound with double-helical chain in the structure. Thereaction of the same metal and ligand under different solvent conditions form1Dcompounds7and8with different SBUs.9is a2D compound and10is a1Dcompound.(2) By adjusting the pH value of the system, modulating the reaction system andadding pillar ligands, eight MOFs (compounds11-18) have been synthesized by thereaction of1,3-PmBDC ligand and different metal centers under solvothermalconditions. Compounds11and12are isostructural and the tetra-nuclear Mn/Zncluster SBUs consist of eight carboxylates and four metal atoms. The tetra-nuclear Mn/Zn cluster is connected to ten organic ligands. Each organic ligand exhibits twodifferent coordination modes, and the two different ligands are connected to two andthree tetra-nuclear Mn/Zn clusters. Compound13is a layered compound withmono-nuclear Cd in the structure, and all of the mono-nuclear Cd atoms are arrangedin a flat plane, two DMA molecules are coordinated at the opposite axial position, byadding pillared ligand pyrazine or4,4’-bipyridine, two3D compounds14and15withdifferent structures were constructed. The7-coordinated Cd atoms are mono-nuclearin the structures of14and15. The mono-nuclear Cd atom in compound14isconnected with one pyrazine molecule and one DMA molecule, but in compound15,it is coordinated with two4,4’-bipyridine molecules. Due to the different connectingmodes of the two compounds, the structure of compound14is dense and theframework of compound15is more open. Compounds16-18are obtained by usingindium nitrate and bismuth nitrate, respectively, only the crystal structure ofcompound16is obtained.16is a2D layered structure with sql topology.(3) Assembly of Mesoporous In-TCPP framework (compound19) by thereaction of functional5,10,15,20-tetrakis (4-carboxyphenyl)-porphyrin (H4TCPP)ligand with indium nitrate under solvothermal conditions with1D In-chain in thestructure. Compound19shows very high thermal stability and water stability.Systemic gas adsorption investigations were executed with activated19sample to testits permanent porosity, such as hydrogen, nitrogen, oxygen, argon, carbon dioxide,methane, ethane, ethylene and propane adsorptions. Both of the nitrogen and argonsorption isotherms at low temperature are displaying typical type-IV sorptionbehaviors and exhibiting a steep increase at the point of P/P0=0.2, which is acharacteristics of mesoporous materials. Compound19exhibits high adsorptionabilities for carbon dioxide, ethane, ethylene and propane. |
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