Adsorption And Separation Properties Of Supramolecular Framework Materials Constructed By Carboxylate Blocks

Compared with the traditional zeolites,mesoporous silicas,and carbons,supramolecular framework materials,as a new class of porous materials,have been introduced into a wide range of well-known applications thanks to their high storage ability,robust structure,tunable pore size and charge,functional pore surface,etc.With the high-speed development of industry,the need of energy is growing and a numerous of contaminants have been released,which would destroy the eco-friendly environment and endanger the health of living things.Therefore,to solve these issues is imperative,which mainly depends on the development of new materials and improvement of technology.Besides,the performance of materials was largely affected by the stability,pore sizes and charges of the skeletal structure.On the basis of the above considerations,this thesis mainly focuses on the construction of novel supramolecular framework materials,which possessed high thermal stability and suitable apertures to adsorption and separation of greenhouse-gas and purification of natural-gas,as well as having favourable solvent stability,large channels,high porosity and specific charge to remove carcinogens.Synthesis of organic building blocks with multiple functional sites and special steric configuration is extremely significant for fabricating high thermal stability and desired framework materials.In this thesis,three organic building units were successfully synthesized and nine novel supramolecular framework materials were constructed by reasonable design.According to the detailed analysis of these structures,the properties of them were investigated.The main results are summarized as follows:1.A pair of homochiral porous supramolecular organic frameworks（SOFs,compounds 1 and 2）was assembled from brand-new enantiopure blocks（5,5′-（（（1R,2R）-cyclohexane-1,2-diylbis（azanediyl））-bis（carbonyl））diisophthalic acid,R-CHBAI and 5,5′-（（（1S,2S）-cyclohexane-1,2-diylbis（azanediyl））-bis（carbonyl））diisophthalic acid,S-CHBAI）via hydrogen-bonding andπ-πinteractions.The frameworks maintain good crystallinity until 250 ^℃ and own robust structure and permanent porosity.Remarkably,the adsorption amount of CO₂ for compound 1 is213 cm³ g^-1 at 195 K under 1 bar.Furthermore,the material not only shows excellent adsorption capacity for CO₂ and C₂H₆ at ambient conditions but also exhibits high selectivity towards CO₂ over N₂ and CH₄ as well as C₂H₆ over CH₄ according to the different gas affinity.The successful construction of compounds 1 and 2 would enlarge the family of SOFs materials,which can act as prospective candidates for industrial applications.Afterwards,a pair of homochiral porous coordination polymers（compounds 3and 4）was constructed by using the same building units under solvothermal conditions.In compounds 3 and 4,each of the zinc unit is coordinated to two oxygen atoms and two nitrogen atoms derived from two different ligands and one ethanediamine molecule,respectively,resulting in the formation of a chain coordination polymer.Then,the independent chains are further anchored by hydrogen-bonds forming a two-dimensional supramolecular architecture.The materials display good stability in water and some polar solvents.2.In order to achieve three-dimensional SOFs materials,nonplanar conformation organic block,2,4,6-trimethyl benzene-1,3,5-triyl-isophthalic acid（TMBTI）,was selected and successfully synthesized.Three novel SOFs（compounds 5-7）were fabricated by using the TMBTI building units in 1,4-dioxane under different reaction conditions.For compound 5,two types of hydrogen-bonds exist in its framework.Compound 6 features a typical honeycomb structure with a large interior channel diameter of 19.3?owing to the well-ordered configuration of homogeneous hydrogen-bonds.By changing the reaction temperature,a three-fold interpenetrated SOF material（compound 7）with a high level of thermal stability was achieved.It is worth mentioning that compounds 5 and 7 take up a significant amount of CO₂,up to308 and 340 cm³ g^-1 at 195 K under 1 bar,respectively,which shows the sufficient improvement over the state-of-the-art SOF-based materials.Besides,the two materials exhibit commendable selective adsorption and separation capacity for CO₂ and light hydrocarbons under ambient conditions.These results indicate that compounds 5 and7 may have potential applications for greenhouse-gas trapping and natural-gas upgrading.3.A novel single-walled metal-organic nanotube（MONT,compound 8）exhibiting rare armchair（3,3）CNT topology was assembled by cross-linking zinc cores and deprotonated 4,4′,4′′-nitrilotrisbenzoic acid（H₃NTB）ligands.The independent nanotubes possess an exterior wall diameter of 29?and an interior channel diameter of 21?,which were further linked by hydrogen-bonds to form a three-dimensional supramolecular architecture with a typical honeycomb structure.Benefitting from the anionic framework,high porosity,and mesoporous channel,compound 8 exhibits excellent capture ability for carcinogenic dyes basic red 9 and basic violet 14 with high adsorption rates and superb adsorption amounts,which enriched the application fields of MONT materials.Furthermore,compound 8 also displays effective separation behaviour for different charged organic dyes.On account of these favourable performances,compound 8 can be an extremely smart adsorbent for the effective removal of cationic dyes.Moreover,an interpenetrated two-dimensional coordination polymer（compound9）was synthesized by connecting zinc ions with H₃NTB and 4,4′-bipyridine.Compound 9 exhibits good stability in water and some polar solvents thanks to the stable secondary building units existing in the framework and theπ-πstacking interactions between two adjacent layers.The adsorption abilities of CO₂ and CH₄ on compound 9 have been investigated and the adsorption selectivity of the material for the mixture of them was calculated by IAST calculating.