Metal–organic frameworks feature a certain framework flexibility, mainly due to a linker mobility inside the lattice. The latter is responsible for effects like breathing or gate-opening, thus making predictions of the sorption and diffusion behavior quite difficult. Permeation measurements on supported UiO-66 membranes at low temperatures and on polymer-coated UiO-66 membrane layers as well as ²H NMR line shape studies and nitrogen sorption measurements of UiO-66 with deuterated linkers in Matrimid as mixed-matrix membranes (MMM) indicate that the 2-site 180° flips (π-flips) of the aromatic ring are hindered by the presence of (i) the surrounding polymer Matrimid and (ii) residual solvent molecules, thus giving profound insights into the molecular understanding of gas transport through metal–organic framework-based MMMs.

中文翻译：

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以UiO-66和Matrimid为例，更好地了解基于金属有机骨架的混合基质膜的优异性能

金属有机框架具有一定的框架灵活性，这主要归因于晶格内部的连接子迁移。后者负责呼吸或开门之类的影响，因此很难预测吸附和扩散行为。在低温下在支持的UiO-66膜上以及在聚合物涂层的UiO-66膜层上以及²个膜上进行渗透测量作为基质矩阵混合膜（MMM）的Matrimid中带有氘化连接基的UiO-66的H NMR线形研究和氮吸附测量表明，芳环的2位180°翻转（π-flip）受阻（i）周围的聚合物Matrimid和（ii）残留的溶剂分子，从而对通过金属-有机骨架的MMM进行气体传输的分子理解提供了深刻的见解。