Stepwise crystallographic visualization of dynamic guest binding in a nanoporous framework.
Stepwise crystallographic visualization of dynamic guest binding in a nanoporous framework.
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DOI：
10.1039/c7sc00267j
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发表时间：
2017-04-01
期刊：
影响因子：
8.4
通讯作者：
Murugesu M
中科院分区：
文献类型：
--
作者：
Brunet G;Safin DA;Aghaji MZ;Robeyns K;Korobkov I;Woo TK;Murugesu M
从结晶学上观察到了气态客体的动态吸收行为，产生了一组独特且不断变化的主客体相互作用，这将推动高容量碘捕获材料的改进。结合部位是所有主客体系统的核心，无论是生物的还是化学的。当考虑与客体形成共价键的结合部位时，我们通常设想一个单一的、高度特异的结合基序。通过单晶X射线结晶学，首次直接观察到在单一吸附位置显示多种共价结合基序的客体的动态结合。介绍了I2在多孔MOF中掺入的逐步结晶学可视化，其中确定了整个吸收过程中的首选结合基序。客体I2分子最初与骨架的末端碘原子结合形成[I4]2-单元。然而，随着吸附的进行，观察到I2分子形成了具有相同骨架碘原子的较不利于能量的I3-基团，从而允许更多的客体分子被化学吸附。在接近饱和时，在相同的孔隙中观察到更多的结合基序，包括物理吸附和化学吸附的客体分子。在这里，我们提出了一组独特的主客体相互作用的成功识别，这些相互作用将推动高容量碘捕获材料的改进。
The dynamic uptake behaviour of a gaseous guest has been observed crystallographically, yielding a unique and ever-changing set of host–guest interactions that will drive the improvement of high-capacity iodine capture materials. Binding sites are at the heart of all host–guest systems, whether biological or chemical. When considering binding sites that form covalent bonds with the guest, we generally envision a single, highly specific binding motif. Through single-crystal X-ray crystallography, the dynamic binding of a guest that displays a variety of covalent binding motifs in a single site of adsorption is directly observed for the first time. The stepwise crystallographic visualization of the incorporation of I2 within a porous MOF is presented, wherein the preferred binding motifs throughout the uptake process are identified. The guest I2 molecules initially bind with terminal iodide atoms of the framework to form [I4]2– units. However, as the adsorption progresses, the I2 molecules are observed to form less energetically favorable I3 – groups with the same framework iodide atoms, thereby allowing for more guest molecules to be chemisorbed. At near saturation, even more binding motifs are observed in the same pores, including both physisorbed and chemisorbed guest molecules. Herein, we present the successful identification of a unique set of host–guest interactions which will drive the improvement of high capacity iodine capture materials.