Crystallization of leucine on a self-assembled monolayer with covalently attached enantiomeric leucine molecules
Crystallization of leucine on a self-assembled monolayer with covalently attached enantiomeric leucine molecules
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DOI：
10.1016/j.colsurfa.2006.02.060
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发表时间：
2006-08
期刊：
影响因子：
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通讯作者：
T. Nakanishi;Naoki Banno;M. Matsunaga;T. Asahi;T. Osaka
中科院分区：
文献类型：
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作者：
T. Nakanishi;Naoki Banno;M. Matsunaga;T. Asahi;T. Osaka
用X射线衍射仪(X射线衍射仪)和原子力显微镜(AFM)研究了手性氨基酸亮氨酸在自组装单分子膜(SAM)修饰的金载体上的结晶行为。发现用SAM修饰的样品在纯的亮氨酸对映体溶液中发生了对映体晶相的形成，其中一种对映体形式的亮氨酸分子共价连接在SAM上。相反，在外消旋亮氨酸溶液中浸泡后，d-亮氨酸和L-亮氨酸连接的自组装膜上都形成了外消旋晶相。在非外消旋溶液中，当一种手性与手性相同的对映体形式过量时，在附着对映体的SAM上同时形成对映体和外消旋晶相，而两种晶体都没有与另一种对映体形式过量形成。利用原子力显微镜(AFM)观察了样品表面形貌的变化，并伴随着SAM上晶相的生长，反映了X射线衍射法得出的结晶度。
Crystallization of chiral amino acid, leucine, on the gold substrate modified with a self-assembled monolayer (SAM) was investigated with X-ray diffraction (XRD) and atomic force microscopy (AFM). It was found that the formation of enantiomeric crystalline phase occurred enantioselectively when the specimen modified with the SAM, to which one enantiomeric form of leucine molecules was covalently attached, was immersed in a pure enantiomeric solution of leucine. On the contrary, a racemic crystalline phase was formed on both d- and l-leucine-attached SAMs after soaking in a racemic leucine solution. In non-racemic solutions, both enantiomeric and racemic crystalline phases were formed on the enantiomer-attached SAM when the one enantiomeric form with the same chirality as the attached enantiomer was contained in excess, while neither of the crystals was formed with the other enantiomeric form in excess. Changes in the surface morphology of the specimens accompanied with the growth of crystalline phases on the SAM, reflecting the crystallinity suggested from the XRD method, were observed by using AFM.