Baumgartner Bettina, Mashita Risa, Fukatsu Arisa, Okada Kenji, Takahashi Masahide
Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University* (* Present name: Osaka Metropolitan University), Sakai, Osaka, 599-8531, Japan.
JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
Angew Chem Int Ed Engl. 2022 Jul 11;61(28):e202201725. doi: 10.1002/anie.202201725. Epub 2022 May 18.
The degree of pore filling is an important parameter for defining guest@MOF properties in applications including electronics, optics, and gas separation. However, the interplay of key aspects of host-guest interactions, such as a quantitative description of the guest alignment or the structural integrity of the host as function of pore filling are yet to be determined. Polarisation-dependent infrared spectroscopy in attenuated total reflection configuration combined with gas sorption allowed to simultaneously study the orientation of the guest molecule and structural changes of the MOF framework during the pore filling process. Thereby we found, that initially randomly oriented guest molecules align with increasing pore filling during adsorption from the gas phase. At the same time, the framework itself undergoes a reversible, guest molecule-dependent rotation of the aromatic linker and a linker detachment process, which induce defects.
孔隙填充程度是定义客体@金属有机框架（MOF）在电子、光学和气体分离等应用中的性质的一个重要参数。然而，主客体相互作用关键方面的相互影响，如客体排列的定量描述或主体结构完整性随孔隙填充的变化，仍有待确定。衰减全反射配置下的偏振相关红外光谱与气体吸附相结合，能够在孔隙填充过程中同时研究客体分子的取向和MOF框架的结构变化。由此我们发现，从气相吸附过程中，最初随机取向的客体分子会随着孔隙填充的增加而排列。同时，框架本身经历了芳香族连接体的可逆的、依赖于客体分子的旋转以及连接体脱离过程，这些过程会导致缺陷。
