Synthesis And Characterization Of New Covalent Organic Frameworks And Their Gas Adsorption Performance

Covalent organic frameworks(COFs)feature good crystallinity,porosity,low density,large specific surface area.Due to their organic property in nature,COFs can be easily modified through either a bottle-up strategy or post-synthesis route.Generally,3D COFs are more ideal gas absorbing material than their 2D counterparts because of their unique features,such as large pore spaces,abundant pores and fully exposed active sites.In Chapter 3,we designed and synthesized a series of AAS-COFs,which were constructed through the condensation reaction of 1,3,5,7-tetra(4-aldehyde phenyl)-adamantane(TFPA)and 3 linear aromatic diamines with different length(phenyl,diphenyl and triphenyl).Three COFs were nominated as AAS-1,AAS-2 and AAS-3,respectively.They have a similar structure,but different pore size,pore volume and spefic surface area.The purpose of this work is to explore the structure-activity relationship between the porosity of COFs and their H2 adsorption capability.This work provides a theoretical basis for COFs used as hydrogen storage materials.In Chapter 4,we designed and synthesized a new type of 3D COF(named 3D COF-Py-Ad),which was constructed by the consendation of1,3,5,7-tetra(4-benzylamino)-adamantane(TAPA)and 1,3,6,8-tetra(4-aldehyde phenyl)pyrene(TFPPy).The 3D COF-Py-Ad possesses a pts topological structure with double-layer interpenetrating network.Besides,3D COF-Py-Ad has a higher surface area and a narrower pore size,which is favotable for the H2 adsorption.It was revealed that high specific surface area,fully exposed active sites of COF-Py-Ad contributed to its good H2 adsorption capability.In Chapter 5,we synthesized two new types of 3D COFs,in which1,3,5,7-tetra(4-aminophenyl)adamantane(TAPA)was used to react with nitrogen-rich porphyrin building block and sulfur-containing tetrathiafulvalene building block,to provide COF-TBAP-Ad and COF-TTF-Ad,respectively.Both COFs are microporous materials with high specific surface area and double-layer interpenetrating network structure.Our experimental results showed that COF-TBAP-Ad has better H2 adsorption performance than COF-TTF-Ad,which can be attributed to the higher conjugated structure of COF-TBAP-Ad.