Construction of a Polyhedral Metal–Organic Framework via a Flexible Octacarboxylate Ligand for Gas Adsorption and Separation

• Published in: Inorganic chemistry 2013-03, Vol.52 (6), p.3127-3132
• Main Authors: Lin, Zu-Jin, Huang, Yuan-Biao, Liu, Tian-Fu, Li, Xiang-Ying, Cao, Rong
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic302583a

A flexible octacarboxylate ligand, tetrakis[(3,5-dicarboxyphenyl)oxamethyl]methane (H8X), has been used to construct a highly porous metal–organic framework (In2X)(Me2NH2)2(DMF)9(H2O)5 (1), which is comprised of octahedral and cuboctahedral cages and shows a rare (4,8)-connected scu topology. Gas adsorption studies of N2, H2 on the actived 1 at 77 K reveal a Langmuir surface area of 1707 m2 g–1, a BET surface area of 1555 m2 g–1, a total pore volume of 0.62 cm3 g–1, and a H2 uptake of 1.49 wt % at 1 bar and 3.05 wt % at 16 bar. CO2, CH4, and N2 adsorption studies at 195, 273, 285, and 298 K and also ideal adsorbed solution theory (IAST) calculations demonstrate that 1 has high selectivites of CO2 over CH4 and N2. The resulting framework represents a MOF with the highest gas uptakes and gas selectivities (CO2 over CH4 and N2) constructed by flexible ligands.