Microporous metal–organic framework with 1D helical chain building units: Synthesis, structure and gas sorption properties

• Published in: Inorganic chemistry communications 2017-09, Vol.83, p.88-91
• Main Authors: Li, Jiang-Tao, Li, Jing, Song, Li-Mei, Ji, Xiao-Hui
• Format: Article
• Language: English
• Subjects: Gas sorption; Helical metal chains; Metal-organic framework; Porous framework
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2017.07.003

The design, synthesis, and structural characterization of a new anionic metal-organic framework, namely, {(H2N(Me)2)[Cu(bidc)](H2O)3}n (1), with 1D helical metal chains is reported here. The title complex was synthesized by solvothermal reaction of Cu(NO3)2·3H2O and benzimidazole-5,6-dicarboxylic acid (H3bidc) in a mixed solvent of DMF, 1,4-dioxane, H2O and HNO3 (aq) at 120°C for three days, which reveals a 3D porous framework with 1D nanotubular channels running along the c axis. The pore characteristics and gas sorption properties of this compound were investigated at both cryogenic temperature and room temperature by experimentally measuring N2, CH4 and CO2 adsorption/desorption isotherms. The amount of the N2 and CO2 uptake is 146cm3/g at 77K and 52cm3/g at 273K, which is the highest among MOFs constructed from the H3bidc ligand. In addition the activated 1 shows high adsorption selectivity of CO2 over CH4 at room temperature. Solvothermal reaction of Cu(NO3)2·3H2O and benzimidazole-5,6-dicarboxylic acid results in a new 3D non-interpenetrating metal-organic framework, whose framework features 1D nanotube channels running along the c axis that are formed by the connection of the benzimidazole-5,6-dicarboxylic acid ligands with the 1D helical metal chains. In addition, the pore characteristics and gas sorption properties of this compound were investigated at both cryogenic temperatures and room temperature by experimentally measuring N2, CO2 and CH4 adsorption/desorption isotherms, which reveals a moderate BET surface area and a high CO2/CH4 selectivity. [Display omitted] •A new Cu(II)-based metal-organic framework was synthesized.•This MOF shows a 3D porous framework with 1D helical metal chains and 1D nanotube channels.•Highly selective adsorption of CO2 over CH4 could be achieved at room temperature.