Song Bai-Qiao, Yang Qing-Yuan, Wang Shi-Qiang, Vandichel Matthias, Kumar Amrit, Crowley Clare, Kumar Naveen, Deng Cheng-Hua, GasconPerez Victoria, Lusi Matteo, Wu Hui, Zhou Wei, Zaworotko Michael J
Department of Chemical Sciences and Bernal Institute, University of Limerick, Limerick V94 T9PX, Republic of Ireland.
School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
J Am Chem Soc. 2020 Apr 15;142(15):6896-6901. doi: 10.1021/jacs.0c01314. Epub 2020 Apr 3.
Closed-to-open structural transformations in flexible coordination networks are of potential utility in gas storage and separation. Herein, we report the first example of a flexible SiF-pillared square grid material, [Cu(SiF)(L)] (L = 1,4-bis(1-imidazolyl)benzene), . exhibits reversible switching between nonporous () and several porous (, , , and ) phases triggered by exposure to N, CO, or HO. In addition, heating to 433 K resulted in irreversible transformation to a closed polymorph, . Single-crystal X-ray diffraction studies revealed that the phase transformations are enabled by rotation and geometrical contortion of L. Density functional theory calculations indicated that L exhibits a low barrier to rotation (as low as 8 kJmol) and a rather flat energy surface. In situ neutron powder diffraction studies provided further insight into these sorbate-induced phase changes. combines stability in water for over a year, high CO uptake (ca. 216 cm/g at 195 K), and good thermal stability.
柔性配位网络中的闭孔到开孔结构转变在气体储存和分离方面具有潜在应用价值。在此，我们报道了首例柔性SiF柱撑方形网格材料[Cu(SiF)(L)]（L = 1,4-双(1-咪唑基)苯），它在暴露于N₂、CO₂或H₂O时会在无孔（）和几种多孔（、、和）相之间发生可逆转变。此外，将加热到433 K会导致不可逆转变为一种闭孔多晶型物。单晶X射线衍射研究表明，相变是由L的旋转和几何扭曲引起的。密度泛函理论计算表明，L的旋转势垒较低（低至8 kJ/mol）且能量表面相当平坦。原位中子粉末衍射研究进一步深入了解了这些吸附质诱导的相变。该材料在水中具有超过一年的稳定性、高CO₂吸附量（在195 K时约为216 cm³/g）以及良好的热稳定性。
