2019年8月6日， 日本電子株式會(huì)社的NMR專家西山博士(YUSUKE NISHIYAMA)在Nature Communications上發(fā)表了一篇論文：Understanding hydrogen-bonding structures of molecular crystals via electron and NMR nanocrystallography。文章中闡述使用TEM和固體NMR可以成功地對(duì)100nm-1um的納微晶體包括氫鍵結(jié)構(gòu)進(jìn)行表征， 文章中注明所使用的設(shè)備為： JEOL 的透射電子顯微鏡（型號(hào) JEM-2200FS）和JEOL的固體核磁共振（型號(hào) JNM-ECZ600R）。
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https://www.nature.com/articles/s41467-019-11469-2
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Visualization of hydrogen-bonding: Electron and NMR nano-crystallography
Product used ：Transmission Electron Microscope (TEM), nuclear magnetic resonance (NMR）
Crystalline structure including hydrogen atoms are now available from nano-to micro-crystals of 100 nm to 1 μm using electron and NMR nano-crystallography approach. The overall crystalline structures can be determined by electron diffraction (ED) which is one of the observation mode of transmission electron microscope (TEM). However, the ED based structures have several problems including 1) invisible hydrogen atoms and 2) mis-assignment of carbon, nitrogen and oxygen atoms. The former brings crucial problems to understand hydrogen bonding networks and the latter results in ambiguous molecular conformation. On the other hand, solid-state NMR can directly observe 1) hydrogen (1H) and 2) carbon (13C) and nitrogen (14N, 15N). Here, we combine ED and solid-state NMR through the first principle quantum computation with the NMR crystallography approach for crystalline structure solution. The method, electron and NMR nano-crystallography, can be applied to nano-to micro-crystals even for mixture samples. First, we have demonstrated the structure solution of L-histidine, whose structure is already known, as a proof of concept. Then, we have solved the crystalline structure of cimetidine form B, whose structure was previously unknown.
The electron and NMR nano-crystallography can be applied to many pharmaceutical samples including pharmaceutical formulation as well as systems, in which only nano-to micro-sized crystals are available, including PCP/MOFs.
Figure: TEM image of cimetidine form B and crystalline structure solved by electron and NMR nano-crystallography.The cimetidine form B is needle shape crystals (indicated by red circle on the left figure) and often fails to form a large single crystal for single crystal X-ray diffraction. In addition, the contamination of form C is often observed, hampering the structural solution by powder X-ray diffraction. Here, we solved the crystalline structure of cimetidine form B for the first time.
C. Guzmán-Afonso?, Y.-l. Hong?, H. Colaux, H. Iijima, A. Saitow, T. Fukumura, Y. Aoyama, S. Motoki, T. Oikawa, T. Yamazaki, K. Yonekura& Y. Nishiyama*, Nat. Comm. in press DOI: 10.1038/s41467-019-11469-2
