Ballbot-type motion of N-heterocyclic carbenes on gold surfaces
Ballbot-type motion of N-heterocyclic carbenes on gold surfaces
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DOI：
10.1038/nchem.2622
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发表时间：
2017-02-01
期刊：
影响因子：
21.8
通讯作者：
Fuchs, Harald
中科院分区：
文献类型：
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作者：
Wang, Gaoqiang;Ruehling, Andreas;Fuchs, Harald
最近，n -杂环碳烯（NHCs）被引入作为表面修饰的替代锚点，因此提供了许多有吸引力的特性，这可能使它们优于硫醇基体系。然而，很少有人研究NHCs在表面的自组织过程，这是形成自组装单层膜（sam）的一个重要方面，这需要分子的迁移性。基于扫描隧道显微镜和第一性原理计算的研究，我们提供了对NHCs高迁移率背后的微观机制的理解。这些NHCs从表面提取一个金原子，从而形成nhc -金配合物，通过球球式运动显示出高的表面迁移率。加上它们的高解吸屏障，这使得形成有序和强结合的sam。此外，该机制允许在表面上互补地辅助合成二聚体和迄今未知的三聚体NHC金配合物。
Recently, N-heterocyclic carbenes (NHCs) were introduced as alternative anchors for surface modifications and so offered many attractive features, which might render them superior to thiol-based systems. However, little effort has been made to investigate the self-organization process of NHCs on surfaces, an important aspect for the formation of self-assembled monolayers (SAMs), which requires molecular mobility. Based on investigations with scanning tunnelling microscopy and first-principles calculations, we provide an understanding of the microscopic mechanism behind the high mobility observed for NHCs. These NHCs extract a gold atom from the surface, which leads to the formation of an NHC-gold adatom complex that displays a high surface mobility by a ballbot-type motion. Together with their high desorption barrier this enables the formation of ordered and strongly bound SAMs. In addition, this mechanism allows a complementary surface-assisted synthesis of dimeric and hitherto unknown trimeric NHC gold complexes on the surface.