通过表面拓化学对比Ullmann合物
Anaïs Mairena1, Christian Wäckerlin1, Martin Wienke2
1Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland.
Journal of the American Chemical Society
|November 2, 2018
概括
9,9'-bisheptahelicene在黄金表面上的自组合产生了50%的半立体过量. 这种立体选择性源于在表面合成过程中表面诱导的地形化学效应.
科学领域:
- 有机化学
- 表面科学
- 超分子化学
背景情况:
- 是具有独特结构和电子性质的性多环芳.
- 在表面合成提供了一个强大的平台来构建复杂的有机分子与控制的架构.
- 了解自组装过程对于设计功能性纳米材料至关重要.
研究的目的:
- 为了研究9,9′- bisheptahelicene在Au(111) 表面的自组装行为.
- 将自组装结果与同一分子的表面合成进行比较.
- 阐明这些过程中的立体选择性因素.
主要方法:
- 使用扫描道显微镜 (STM) 来研究9,9′- bisheptahelicene在Au上的自组.
- 通过乌尔曼合进行了 9- 乙烯的表面合成,以获得目标分子.
- 通过对STM图像的分析,可以确定二聚体比率.
主要成果:
- 9,9′- bisheptahelicene在Au(111) 上的自组合导致 (M,P) -meso形式的二聚体过量 (de) 为50%.
- 表面合成也产生了相同的二聚体过量,表明一致的立体化学结果.
- 观察到的立体选择性归因于地形化学效应.
结论:
- 在表面合成过程中,反应物和中间体的表面对齐有利于 (M,P) 过渡状态.
- 在表面介导反应中,拓化学控制是实现高立体选择性的关键因素.
- 这项研究提供了关于有机分子在表面上具有特定空间排列的理性设计的见解.
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