| Metal organic frameworks(MOFs),consisted with inorganic metal nodes and organic rigid ligands,are a new type of inorganic porous material ordered in two or three dimensions.MOFs have very distinctive features,such as diverse structure,easily designable,and high surface area.Therefore,since they were discovered in the early 21st century,they have attracted the attention of many researchers in the past two decades nd have been displayed potential important applications in many fields,especially in catalysis.At present,how to use the characteristics of metal organic framework to carry out organic transformations,achieve efficient and high selective conversion of substrates and sustainable reaction conditions is an important challenge for chemists.In addition,how to use various instruments to understand the role of MOFs in the catalytic process and the reaction mechanism are also important opportunities and challenges in this Multidisciplinary field.This thesis focused on the application of MOFs in organic catalytic reactions.Firstly,an introduction and overview of the development history of MOFs was given,followed by a briefly list of several MOFs commonly used in organic catalysis.Next,according to the different catalytic sites in MOFs,the examples of development status of MOFs catalyzed organic reactions were reviewed.MOFs have a well-characteric structure,high surface area and stable properties,and are very suitable for acting as heterogeneous catalysts or catalyst supports.Directed by the idea that designed and founctionlized MOFs can act as new heterogeneous catalyst,and the basic laws of organic chemistry,the research of this work uses chemical modification to incorporate functional sites and metal complex into MOFs,and then carried out a series of methodological studies.At the same time,with the help of computational chemistry and characterization methods,the reaction mechanism has been explored,and some intermediates and reaction pathways of MOFs catalyted organic reactions were shown.The main research results of the thesis are as follows:1.Based on the propoties of organic system,the highly compatible UiO-67 was selected as the start of designing the heterogeneous catalyst.By modifying the dicarboxylic acid ligand in the MOFs,a specific functional group is introduced as the anchor point of the metal catalyst.Further,catalytically active Ti-MOFs are obtained.This catalyst can not only realize the hydroboration reaction of the carbonyl compound with high efficiency and high selectivity under mild conditions,but also can be recycled many times.This catalyst combines the advantages of homogeneous catalysts and heterogeneous catalysts,which is,it employed organometallic complexes as active site and also can be recycled.This work provided a new idea for the application of homogeneous organic reactions in insdutral production.2.Based on previous exploration,in order to achieve high selectivity sp~3 inert carbon-hydrogen bond activation reaction of methane,MOFs with a carboxylic acid ligand containing phenoline molecular skeleton was designed and synthesized succssfully.And iridium catalytic metal sites were introduced into this new MOFs.The pore size and shape selectivity of the framework were used to easily suppress the thermodynamically superior bisboration product,and the reaction was controlled in the step of methane monoboration reaction,which realized the highly selective activation of methane.This catalyst has different reaction mechanisms than homogeneous catalytic systems and mechanism cycle was also proposed here.3.Copper is a cheap metal that commonly used in organic reactions.Compared to precious metals,copper is cheap but has some inferior catalytic ability for some reactions.Thus a Cu-MOF catalyst was designed and synthesized based on functionalized MOFs,and it was applied in the alkyne coupling reaction and C-H oxidation reaction.More detailed results and mechanism research are still underway. |
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