| Metal-organic framework materials,with excellent maneuverability and predesign for tuning pore size and internal environment,have been identified as an excellent platform to explore high-performance functional materials and extensively studied in the fields of gaseous fuels storage,industrial gas mixtures separation,and organic pollutants removal.In this thesis,we employed metal nodes in combination with tetradentate-carboxylic organic ligands to successfully design and synthesize seven MOFs via introducing auxiliary ligands or changing the solvent reaction systems.These target MOFs capable of adsorbing specific guest molecules were pre-designed and synthesized for organic dye removal and difficultto-separate gas components refinement by means of tuning and optimizing the pore structure and fixing specific functional sites.Based on the pore environment engineering design philosophy,MOFs were endowed with multiple functional porosity and pore chemistry.Herein,our research work realized the customization of high-performance MOFs materials for corresponding application scenarios,mainly including the following three parts:The self-assemble of selected X-shaped tetracarboxylic ligand H4 TPTA {[1,1’:3’,1’’-terphenyl]-4,4’,4’’,6’-tetracarboxylic acid} and N-donor ancillary ligand(1,2,4-triazole and4,4’-bipyridine)successfully constructed three novel Zn-MOFs(Zn TPTA-1/2/3).Based on the pillared-layer strategy,Zn TPTA-1 constructed by the ancillary ligand 4,4’-bipyridine shows oversize aperture and without functional sites.Clipping the pore size through removement of bipyridine,ZnTPTA-2 exhibits shrunken multi-level pore sizes and highdensity functional O sites modified on the inside of the pore surface,which facilitate it effectively separating gas mixtures.To further boost the separation performance,Zn TPTA-3 with size-adapted aperture integrated O/N binding sites is obtained by introducing a pore partition agent 1,2,4-triazole.The strengthened affinity between the framework and C2H2 lead to outstanding sieving effect and higher selectivity.Combined with cycling dynamic breakthrough experiments and DFT theoretical calculation,it exhibits the significance of pore environmental engineering for efficient separation of the targeted gas molecule.An effective strategy was developed through solvent-induced effects and flexibility of ligand conformation to successfully make two In(Ⅲ)-MOFs(In TPTA-1/2),showing topological diversity and different stability.In TPTA-1 in the assemble of mono cluster In and tetracarboxylic created a pts network structure with 1D nanometer tube channels to highefficiently remove carcinogenic dyes.In TPTA-2 belongs to fsc network constructed with the infinite extended zigzag {In-OH-In}n chain as SBUs to build a micropore environment.Benefiting from the μ2-OH-groups and a square hole 5.6 ? of the potential to provide more suitable pore confinement effects,it exhibits extraordinary selectivity of CO2/CH4 and C2H2/CH4.The outstanding reusability and high chemical stability make In TPTA-2 a promising candidate for the separation of these binary mixtures in practical application.Based on the reticular chemistry theory,two novel functionalized MOFs(Cd DDBP and Mn DDBP),were successfully synthesized by the N-site-containing tetracarboxylic acid ligand H4 DDBP.Cd DDBP exhibits a typical highly polarized pore environment with highdensity open metal site binding centers,resulting in preferential adsorption behavior of C2H2 and C2H4.The dodecahedral molecular cage structure is formed in the multi-coordination mode of the tetranuclear Mn clusters,so Mn DDBP has the pore surface mainly composed of low-polarity aromatic rings and without open metal sites.Due to higher pore volume,Nfunctionalized pore surface and restricted pore size,Mn DDBP displays the splendid C2H6/C2H4 selectivity,enabling preferential binding of ethane over ethylene.In addition,Mn DDBP showed a good storage capacity for the high molecular polarizability C3H8 gas.At the low pressure,the C3H8 isotherm showed a sharp increase in adsorption and very low adsorption of methane,which enabled Mn DDBP to excellently ensure the separate of C3H8/CH4 gas mixture. |
