Divergent Kinetic and Thermodynamic Hydration of a Porous Cu(II) Coordination Polymer with Exclusive CO2 Sorption Selectivity

• Published in: Journal of the American Chemical Society Vol. 136; no. 31; pp. 10906 - 10909
• Main Authors: Du, Miao, Li, Cheng-Peng, Chen, Min, Ge, Zhi-Wei, Wang, Xi, Wang, Lei, Liu, Chun-Sen
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 06-08-2014
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja506357n

Selective adsorption and separation of CO2 are of great importance for different target applications. Metal–​organic frameworks (MOFs) represent a promising class of porous materials for this purpose. Here we present a unique MOF material, [Cu(tba)2] n (tba = 4-(1H-1,2,4-triazol-1-yl)­benzoate), which shows high CO2 adsorption selectivity over CH4/​H2/​O2/​Ar/​N2 gases (with IAST selectivity of 41–68 at 273 K and 33–51 at 293 K). By using a critical point dryer, the CO2 molecules can be well sealed in the 1D channels of [Cu(tba)2] n to allow a single-crystal X-ray analysis, which reveals the presence of not only Cδ+H···Oδ− bonds between the host framework and CO2 but also quadrupole–​quadrupole (CO2 δ−···δ+CO2) interactions between the CO2 molecules. Furthermore, [Cu(tba)2] n will suffer divergent kinetic and thermodynamic hydration processes to form its isostructural hydrate {[Cu(tba)2](H2O)} n and a mononuclear complex [Cu(tba)2(H2O)4] via single-crystal to single-crystal transformations.