Two pillared-layer metal-organic frameworks (MOFs; PMOF-55 and NH2-PMOF-55) based on 1,2,4-triazole and terephthalic acid (bdc)/NH2-bdc ligands were assembled and display framework stabilities, to a certain degree, in both acid/alkaline solutions and toward water. They exhibit high CO2 uptakes and selective CO2/N2 adsorption capacities, with CO2/N2 selectivity in the range of 24-27, as calculated by the ideal adsorbed solution theory method. More remarkably, the site and interactions between the host network and the CO2 molecules were investigated by single-crystal X-ray diffraction, which showed that the main interaction between the CO2 molecules and PMOF-55 is due to multipoint supramolecular interactions of C-H⋯O, C⋯O, and O⋯O. Amino functional groups were shown to enhance the CO2 adsorption and identified as strong adsorption sites for CO2 by X-ray crystallography.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- X-ray diffraction
- carbon dioxide
- metal-organic frameworks