The Structural Stabilities And Gas Uptakes Of Micro-Porous Metal-Organic Frameworks

Metal-organic frameworks （MOFs） have attracted a great deal of recent interestas a new class of tailor-made functional materials in many application areas. ManyMOFs have been obtained which possess extremely large solvent-accessible voidspace and large open channels. However, such open-structure MOFs tend to undergosignificant structural distortions upon removal of the solvent molecules to lose theirpermanent porosity as probed by the uptake of small molecules （such as N2, H2, andCO₂）. New strategies must be developed to rigidify and stabilize such open-structureMOFs in order to exploit them for gas storage and separation applications.1. Based on the linear triazole carboxylate ligand, an unusual double-walledMicro-Porous MOF possessing the extremely high stability and efficient permanentporosity. Comparing with these two similar ligands, this modification, changing theframework structure from single-walled to double–walled, significantly enhanced theframework stability and increased the void porosity and H2uptake capacity.2. Based on the triangluar-shaped ligand, a MOF with zigzag narrow channels,was solvothermally synthesized and structurally characterized. It possesses a highadsorption capability, which can attribute to the strong interactions between small gasmolecules and the irregular open channels with zigzag shape and narrow pore size.3. Two high-connectivity MOFs with very interesting modes of mixed-motifinterpenetration and cross-linking were synthesized using the elongated andaromatic-rich bridging ligand. Unusual mixed-motif interpenetration andcross-linking can rigidify and stabilize the frameworks, leading to highly porousMOFs with high uptake capacities for H2and CO₂.4. Exposure to CH2Cl2at room temperature induces single-crystal tosingle-crystal transformation of the2D coordination network to the3D metal-organicframework via dimerization of the metal-connecting points, leading to significantenhancement in framework stability, porosity, and H2uptake capacity.