Using the first steps of hydration for the determination of molecular conformation of a single molecule.
Using the first steps of hydration for the determination of molecular conformation of a single molecule.
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DOI：
10.1021/ja506762t
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发表时间：
2014-09
影响因子：
15
通讯作者：
J. Henzl;K. Boom;K. Morgenstern
中科院分区：
文献类型：
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作者：
J. Henzl;K. Boom;K. Morgenstern
确定单个分子的精确结构是高分辨率显微镜的最终目标。然而，扫描隧道显微镜（STM）的分辨率本质上受限于分子轨道的范围，分子轨道通常不会因分子构象的微小变化而有所不同。在这里，我们使用水分子在Au（111）上的偶氮苯衍生物的第一水合步骤期间的位置来确定不仅端基相对于苯环的取向，而且两个苯环相对于偶氮基团的取向。利用低温扫描隧道显微镜（STM）研究了4，4 '-羟基偶氮苯和水分子在Au（111）表面的共吸附。水分子仅与偶氮苯衍生物的羟基端基连接。主要是两个羟基指向相反方向的反式偶氮苯分子被吸附。通过在相同的惰性表面上将单个水分子连接到4-苯胺基-4 '-硝基偶氮苯上证实，该方法通常适用于具有适当端基的分子的结构测定。因此，我们的研究提供了前所未有的信息的分子内取向的基础上的第一个真实的空间观察的水合功能分子。
Determination of the exact structure of individual molecules is the ultimate goal of high-resolution microscopy. However, the resolution of scanning tunneling microscopy (STM) is intrinsically limited to the extent of molecular orbitals, which frequently do not differ for small changes in the molecular conformation. Here we use the position of water molecules during the first hydration steps of an azobenzene derivative on Au(111) to determine not only the orientation of the end groups with respect to the phenyl rings but also the orientation of the two phenyl rings with respect to the azo group. We investigate the co-adsorption of 4,4'-hydroxy-azobenzene and water molecules on Au(111) by low-temperature STM. The water molecules are attached exclusively to the hydroxyl end groups of the azobenzene derivatives. Predominantly the trans-azobenzene molecule with the two hydroxyl groups pointing into opposite directions is adsorbed. As corroborated by the attachment of a single water molecule to 4-anilino-4'-nitro azobenzene on the same inert surface, the method is generally applicable for structure determination of molecules with appropriate end groups. Our study thus gives unprecedented information about the intramolecular orientation based on the first real space observation of the hydration of a functional molecule.