Study On Design,synthesis And Application Of Covalent Organic Frameworks Based On Oxyaromatic Rings

Covalent Organic Frameworks(COFs)are a kind of porous crystalline polymers with periodic network structures formed by the covalent linkages of organic linkers.Due to the characteristics of regular pore channels,low density,high crystallinity and good stability,COFs have a wide range of potential applications in gas storage and separation,catalysis,photoelectricity,adsorption and drug delivery.In this thesis,several COFs were designed and synthesized for the first time,their structures were characterized in detail,and their applications in dye adsorption and drug delivery were initially explored.In Chapter 2,four di-connected and three tri-connected monomers were synthesized,and three [3 + 3]-linked phenoxazine-based new COFs were successfully synthesized.COF-X1,COF-X2 and COF-X3 resulted from the link of 10-(4-aminophenyl)-3,7-phenoxazinediamine as a substrate with 1,3,5-tris(3-hydroxy-4-formylphenyl)benzene,1,3,5-tris(4-formylphenyl)benzene and 10-(4-formylphenyl)-3,7-phenoxazinedialdehyde,respectively.According to PXRD,FTIR,BET,TGA and the molecular simulation,the obtained COFs all present a two-dimensional layers of AA stacking structure.The adsorption experiments of selected dyes show that the synthesized COFs have a higher adsorption rate,and COF-X1 can achieve a high removal rate of Congo red dye at 50% in 1 min.In Chapter 3,two tri-connected aryl triethyl ketone monomers were synthesized.COF-X4,COF-X5 and COF-X6 based on benzopyranium grew out of the link of 1,3,5-tris(4-acetylphenyl)benzene as a substrate with 3,3’-dihydroxy-4,4’-biphenyldialdehyde,2,5-dihydroxyterephthalaldehyde and 1,5-dihydroxy-2,6-naphthalenedialdehyde,respectively.The data of PXRD,FTIR,BET,and TGA show that the structures of the obtained cannot match the classic models built by the molecular simulation,and may be more complex ones.The preliminary drug loading test results show that the three materials have a good drug loading and encapsulation rate for rhodamine B isothiocyanate.The drug loading rates are higher than 70%,and the encapsulation rates are about 80%.Intracellular experiments show that the materials are basically harmless to the cells,which provides a possibility for their application in drug delivery in the future.