关键词: 金属有机骨架, nia拓扑, 二氧化碳吸附, 自组装

Nia topology is 3D structure which is constructed by octahedral and trigonal prism building blocks. In order to obtain Metal-organic Framework (MOFs) with nia topology, we can connect ligands with octahedral configuration and metal clusters with trigonal prism configuration. The typical metal clusters with trigonal prism configuration are M₃O (M=metal, M is trivalent) or M₃OH (M is divalent). In this article, a dendritic ligand 1,3,5-tris(3,5-di-(4-carboxy-phenyl-1-yl)phenyl-1-yl)benzene (TDCPB) with ten phenyl rings and an octahedral configuration is designed and synthesized. We used the metal salt of NiCl₂ and the octahedral ligand of TDCPB to construct a MOF (JUC-105) with nia topology in solvent thermal condition. (Details: In a 20 mL reactor, NiCl₂·6H₂O (30 mg) and the dendritic ligand TDCPB (10 mg) are added to a solvent of Dimethylacetamide (DMA, 3 mL), and then 3 drops of HBF₄ solution are added. After ultrasonic diffusion for 2 min, it is heated at 100 ℃ for 72 h to obtain green single crystals) Single crystal diffraction is used to characterize its structure. JUC-105 crystallizes in P-62c space group. JUC-105 is constructed by Ni₃OH cluster and TDCPB with a 3D structure. The dimension of the large channel is about 1.1 nm. X-ray diffraction and thermogravimetric analysis are used to analyse its thermal stability. The gas uptake of JUC-105 is also tested. It is found that JUC-105 does not have N₂ adsorption. It may be because the weak stability of the structure after the guest molecular removed. However, this MOF has a CO₂ uptake of 24 mL/g at 273 K, 1 atm. After the collapsing of the structure, windows of the pores are blocked and the dimension of the pore is much smaller. Therefore, the N₂ molecules can not be adsorbed. Because the CO₂ have smaller dimension than N₂ molecules, and it can pass through the small windows, the structure still have a comparative CO₂ adsorption.

Key words: Metal-organic Framework (MOF), nia topology, CO₂ adsorption, self-assembly