Synthesis,Characterization,and Catalytic Application Of Pyrazine-Linked Covalent Organic Frameworks

Covalent organic frameworks(COFs)are a class of crystalline porous polymers that is first reported in 2005 as a new type of porous materials by Yaghi group.Since its outstanding characters such as regular structure,low density,large specific surface area and easy surface modification,this materials have attracted wide attentions in areas such as catalysis,photoelectricity,gas adsorption and storage.Until now,a lot with different functions and applications have been synthesized.However,the reactions for the synthesis of COFs are still limited and the syntheses are often complicated.Meanwhile,the stability of COFs is also limited.For example,borate based COFs are sensitive to water and oxygen,and the imine based COFs are not stable in the acid and base.Therefore,searching for new reactions for the synthesis of COFs with high stability is one of the hot research areas in this field.So this thesis focuses on the design and synthesis of pyrazine-linked COFs material.Furthermore,we studied the application of this material in catalysis.This thesis mainly includes the following aspects:In Part 1,we demonstrated the research in COFs,focusing on the reaction type for the synthesis and characteristic of COFs.Also,we brief introduced the applications of COFs.In Part 2,we showed the synthesis of two phenazine-linked COFs.We adopt the common solvent thermal reaction and use 1,2,4,5-benzenetetraamine tetrahydrochloride,3,3’-diaminobenzidine and 2,3,6,7,10,11-hexahydroxytriphenylene as starting material to gain two different COFs,named PZ-COF-1 and PZ-COF-2 respectively.After that,we characterized these materials by powder X-ray diffraction(PXRD),scanning electron microscopy(SEM),fourier transform infrared(FTIR),solid-state nuclear magnetic resonance(NMR)and transmission electron microscopy(TEM).In Part 3,we explored the applications of PZ-COFs in gas storage(H2,CH4 and CO2)and the catalysis with the assist of manganese ions.We found that the composites of COFs and manganese ions show high catalytic activity,and the catalytic activity can still maintain after several cycles,which illustrates that the composite material has good potential application in catalysis.