Synthesis And Properties Of Functional Metal-Organic Framework Materials

Metal-Organic Framework（Metal-Organic Framework）materials is a new type of crystalline materials formed by self-assembly of inorganic metal ions or metal clusters and organic ligands.It also combines the advantages of inorganic materials and organic polymers,with high specific surface area,designable structure and function,and adjustable pore size,etc.,have huge application prospects in the fields of gas adsorption and separation,catalysis,chemical sensing,proton conduction,and biomedicine.However,MOF materials generally have poor stability,especially mechanical stability,which is difficult to meet industrial processing and applications.It is of great significance to prepare and synthesize MOF porous materials with high stability and reveal the relationship between the structure of MOF materials and mechanical properties.In the second chapter,we reported a typical case of dissolution-recrystallization structural transformation（DRST）,which starting from the two-dimensional mononuclear Cu（Ⅱ）framework ZZY-1 based on 2-positional nitrogen atoms of the ligand TTTMB（1,3,5-tris（1,2,4-triazol-1-ylmethyl）-2,4,6-trimethylbenzene）not participating in the coordination,the three-dimensional framework ZZY-2 or ZZY-3with higher stability was successfully obtained through the DRST process.The formation of coordination bonds between the uncoordinated 2-positional nitrogen atoms in the structure of ZZY-1 and the additional Cu（Ⅱ）introduced the conversion process,and accompanied by the in-situ reduction of Cu（Ⅱ）to Cu（I）,as well as HCOOH by acting as a template for the growth of cuprous clusters and controlling the p H value of the reaction system has a decisive effect on the transformation.Cu（Ⅰ）-based ZZY-2 and ZZY-3 had low energy band gaps to efficiently degrade methyl orange in the aqueous solution in the presence of H₂O₂ with or without photo-irradiation,which has more practical significance in wastewater treatment.This work has guided significance for synthesizing high stability MOF materials with novel structures and realizing the practical application of MOF materials.In the third chapter,we designed and synthesized the first two-dimensional layered MOF material ZZY-5[（Mn₃O₂）L1₃（H₂O）₄（DMF）₂·（Mn₃O₂）L1₃（H₂O）₆]which could sense to different properties and forces.When under the action of the shear force generated during grinding,the fluorescence blue-shifted and the intensity remained basically unchanged;under the action of the hydrostatic pressure generated by the diamond anvil cell,the fluorescence red-shifted and the intensity rapidly weakened to almost quenching.The difference is that when the ligand L1 with AIE properties was under the action of shear force and hydrostatic pressure,the fluorescence had red-shifted and the intensity is weakened.The detailed mechanism requires further study.Finally,we started from the three-dimensional porous anion framework material based on trinuclear manganese clusters（Mn₃O）,and gradually introduced Fe（Ⅲ）into the metal nodes of the framework through post-modification synthesis to obtained a series of materials Fe@ZZY-7,which gradually changes the framework from negatively charged to neutral,until positively charged,and the proton conductivity of samples with different Fe（Ⅲ）content was further tested.As the electrical properties of the framework change,the proton conductivity of the material underwent a process of first decreasing and then increasing.MOF materials are generally poor in conductivity,and pressure can change the distance between atoms and the overlap of adjacent electron orbits,thereby changing the properties of the material.We conducted research on the conductivity of MOF materials doped with different Fe（Ⅲ）contents under high pressure.