Synthesis And Adsorption Properties Of Metal-Organic Frameworks Based On N-Containing Carboxylate Ligands

Metal organic frameworks?MOFs?have great potential applications such as gas adsorption and separation,fluorescence and catalysis due to their rich topology,tunable pore size and many other advantages.The nature of MOFs is closely related to the structure.Therefore,the key to MOFs research is to design a target structure according to the natural applocation.Besides,introducing functional active sites into the structure is conducive to improving MOFs performance.Currently,nitrogen-containing carboxylic ligands are widely used in the construction of novel MOFs and gas adsorption and separation because of their rich coordination modes.In this paper,we explored the structure and properties of MOF materials by synthesizing novel carboxylate containing ligands.The first chapter is the introduction part,which introduces the construction,synthesis methods,current status and topic significance of MOFs materials.In the second chapter,three novel MOFs[Zn₂L?OH?]·0.5H₂O?1?,[Co₂L?OH??H₂O?]·5.5H₂O?2?and[Cu₂?HL?]?3?were synthesized under hydrothermal reactions by using a novel triazole carboxylic acid ligand H₃L and three different metal oxygen clusters,namely,Zn₄?COO?₆,Co₄?COO?₆ and Cu₄?COO?₄.The methane separation capacity of compound 1 and the gas adsorption capacity of compound 2 were studied by experiments.In the third chapter,two novel MOFs[Cu₄?L₀?₂?H₂O?₃]·20H₂O?4?and[Y₂?L₀??H₂O?₈]·2?NO₃??5?with dual functionalities of open metal sites and Lewis basic sites based on a designed U-shaped ligand was synthesized by hydrothermal method.In the compound 4,O_h type of cage is a chiral cage,because we can't find any necessary symmetry operations in it.Adjacent O_h type of cages are reciprocal enantiomers for each other to further testify its chirality.Compound 4 exhibits high-capacity of CO₂,C₂ and C₃ hydrocarbon storage capacity under atmospheric pressure.Besides,Ideal adsorbed solution theory?IAST?calculation and Breakthrough experiments show that 4 has a significantly higher adsorption capacity for CO₂,C₂H₆ and C₃H₈ than CH₄.The selective adsorption properties of 4 make it a promising candidate for methane purification.In the forth chapter,two novel V sharped semi-rigid ligands?H₄L₁ and H₃L₂?containg amio and carboxlyic acid groups were synthesized,H₄L₁ and Cu²⁺were self-assemblyintotwoperiodicthree-dimensionalMOFsmaterial,[Cu₃?L₁?₂?DMF?]·?H₃O?₂·3DMF?6?and[Cu₂?L₁??DMF?₂]?2DMF?7?,H₃L₂ and Cu²⁺were self-assembly into one 3D MOF material,[Cu₄?L₂?₃?HL₂??H₂O?₄]?4H₂O,?8?Compound 6 contains dual functionalities of open metal sites and Lewis basic sites,besides,there are two kinds of one-dimensional channel with different shapes and sizes,Compound 6 exhibits moderately high-capacity of acetylene storage capacity under atmospheric pressure,in addition,Ideal adsorbed solution theory?IAST?calculation shows moderately high adsorption selectivity for C₂H₂/CH₄ and C₂H₂/N₂at room temperature,concluded that compound 6 is an ideal candidate for acetylene storage and purification.In the last chapter,a comprehensive study was made on the design and application of novel Nitrogen-containing carboxylic acid ligands used in the construction of MOFs materials to the related properties.