Tianjin Key Laboratory of Structure and Performance for Functional Molecules, MOE Key Laboratory of Inorganic-Organic Hybrid Functional Material Chemistry, College of Chemistry, Tianjin Normal University , Tianjin 300387, P. R. China.
J Am Chem Soc. 2014 Aug 6;136(31):10906-9. doi: 10.1021/ja506357n. Epub 2014 Jul 29.
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 C(δ+)-H···O(δ-) 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}n and a mononuclear complex [Cu(tba)2(H2O)4] via single-crystal to single-crystal transformations.
选择吸附和分离 CO2 对于不同的目标应用非常重要。金属有机骨架（MOFs）是一种很有前途的多孔材料，可用于实现这一目标。在此，我们提出了一种独特的 MOF 材料 [Cu(tba)2]n（tba = 4-(1H-1,2,4-三唑-1-基)苯甲酸酯），它对 CO2/CH4/H2/O2/Ar/N2 气体具有高的吸附选择性（在 273 K 时，IAST 选择性为 41-68，在 293 K 时为 33-51）。通过使用临界点干燥器，可以将 CO2 分子很好地封存在 [Cu(tba)2]n 的 1D 通道中，从而进行单晶 X 射线分析，这表明不仅存在主体框架与 CO2 之间的 C(δ+)-H···O(δ-)键，而且 CO2 分子之间还存在四极矩-四极矩（CO2(δ-)···(δ+)CO2）相互作用。此外，[Cu(tba)2]n 将经历发散的动力学和热力学水合过程，通过单晶到单晶的转变形成其等结构的水合物 {Cu(tba)2}n 和单核配合物 [Cu(tba)2(H2O)4]。
