Synthesis Of Water-stable Carboxylic Acid Metal Organic Framework Compounds

Metal-Organic Frameworks(MOFs)are novel crystalline materials,having attracted great interest of people in many fields including fluorescence,magnetism,hydrogen storage,catalysis,gas storage and separation,ion exchange,sensing and drug delivery due to their great potential in applications.This thesis is divided into four chapters.The chapter one introduces the definition,properties,synthesis,applications,the current study of hydrothermal stability,and summarized the research progress of the relevant studies on the carboxylate ligand based Al-MOFs and MOFs based on the tertrahedral carboxylic acid ligand,Tetrakis(4-carboxyphenyl)silane(TCS).In chapter two,three compounds Cu(TCS)(H2O)(1),Co(TCS)(BPBZ)(2),Ni(TCS)(BPBZ)(3)were synthesized by two ligands Tetrakis(4-carboxyphenyl)silane(TCS)and 1,4-bis(4-pyridyl)benzene(BPBZ)with Cu(NO3)2·3H2O,Co(NO3)2·6H2O,Ni(NO3)2·6H2O respectively,they were fully characterized.They were found having 2D porous structures,as well as good hydrothermal stability.The experimental results show that the alkalinity of BPBZ is weaker than 4,4'-bipy as well as the coordination ability.Therefore,the ability of BPBZ to take off protons of the carboxylic acid is weaker than that of 4,4'-bipy.We not only have some contribution on making hydrothermally stable MOFs,but also found a way to control the degree of depriving the protons of carboxylic acid ligand by introducing N-containing ligands with different basicities.Also,we found that the relative ligand coordination capacity is not fixed but related to the metal center.It is very difficult to obtain single crystals of Al-MOFs based on carboxylate ligands,affecting the development of the Al-MOFs materials.In the third chapter,we obtained a 27×14×5 ?m single crystal(TEM)of a Al-MOF;MIL-53(Al)by adding HF,we plan to further verify its single crystal nature by the X-ray single-crystal diffractometer.This method is expected to be applied to synthesize single crystals of unknown Al-MOFs based on carboxylate ligands,thereby prompting the development of Al-MOFs materials.In addition,we also studied the effect of water contents,reaction temperature,reaction time,and variety of small coordinating agents on the purity,yield and morphology of MIL-53(Al).The study found that the best synthetic conditions for high yield and purity of MIL-53(Al)need the reaction temperature of 220 ? and the reaction time of 3 d.The best molar ratio of Al(?)to terephthalic acid is 1:1,giving a yield of 86%,while the commonly applied 1:0.5 gives a 78%yield.Among the various coordinating agents,only HF gives MIL-53(Al)granules having a single-crystal morphology.In the fourth chapter,the findings of this thesis are summarized,and the prospect of our work and future works are proposed.