Synthesis,Structures And Proton Conductivity Of Metal-organic Frameworks

Metal-Organic Frameworks?MOFs?also known as Porous Coordination Polymers?PCPs?is made of metal ions / cluster?also called as Secondly Building Units,SBUs?and organic ligands.This material has good application prospect in the filed of adsorption /separation,conductive,catalysis,fluorescence,ferroelectric,magnetism and bio-medicine and so on because the structure of MOFs can be designed?the hole size can be adjusted,the hole wall can be functionally modified and it is highly crystalline.The scientists have stared the study on the properties of the MOFs as proton conductors since the MOFs material was known that it can be used as proton conductors,and in recent years,the filed has be developed rapidly which makes the application mature.The core component of the proton exchange membrane fuel cell is proton exchange membrane which could separated from fuel and oxidant in the cell but allow the protons pass freely and the proton exchange membrane decides the cell life and performance.The chemists have build up a large number of MOFs materials which have excellent electrical performance by changing the type of ligands,reaction conditions and so on,and to improve the electrical performance by various modifiction methods which make this application more mature and have laided a solid theoretical basis for practical applications.In this thesis,our main work includes the following two parts:1.We based on the MIL-88 B structure and use organic ligands with different functional groups and chromium ion to build up homogeneous MIL-88 B structure to study the effect and improvement of different ligands on the proton conductive.In addition,we explored the anhydrous proton conductive of MIL-88 B structure by dopping different ligands.We used the ligands such as terephthalic acid,2-aminoterephthalic acid,2-methylterephthalic acid,2,5-dimethylterephthalic acid and chromium ion to synthesis homogeneous MIL-88 B structure,and we also loaded the auxiliary ligand tpt into the structure to open the framework,in the end,we studied the proton conductive of Cr-MIL-88 B,Cr-MIL-88B-NH₂ and Cr-MIL-88B-tpt under different humidity.Besides,we used different ligands to synthesis four coordination polymers which were maked different ligands and tested preliminarily the anhydrous proton conductive.We found that the coordination polymers of Cr-MIL-88 B owned good proton conductive.2.We designed and synthesized a rigid carboxylic acid ligand L₁,5-benzyl thiol isophthalic carboxylic acid ligand,and a flexibility carboxylic acid ligand L₂,1,2-di?2-sulfonic acid group-4-carboxylic acid phenyl oxygen?ethane.We used the rigid ligand L₁ and copper nitrate to synthesize two three-dimensional crystal polymer1 and polymer 2 by solvothermal method.The X-ray single crystal diffraction analyses reveal that the polymer 1 crystallizes in the triclinic space group P-1.The structure has two kinds of copper clusters which are linked by ligands to form a 1D hole along a axis direction of the structure.The X-ray single crystal diffraction analyses reveal that the polymer 2 crystallizes in the tetragyric space group I4/m.The polymer 2 was based on the synthesis of polymer 1 by adding ethanol solution of triphenylphosphine.The binucleaer copper clusters are linked by ligands to form two different cage structures.Two homeomorphism rare earth coordination polymers 3and 4 are obtained by solvothermal method based on the flexible carboxylic acid ligand and different rare earth nitrates.The X-ray single crystal diffraction analyses reveal that this coordination polymer 3 crystallizes in the triclinic space group P-1.There are two different 1D channel along the a axis direction of the structure which are all surrounded by six ligands and eight metal ions,and all sulfonic acid groups are located in the 1D channel,which exhibits very good hydrophilic,but the framework of polymer 3 will collapse in the water because of the existence of Na+,which can not be conducted with water,in addition,it has no anhydrous proton conductive due to the large distance between the sulfonic acid groups which can not form the hydrogen-bond network.