Department for Earth and Environmental Sciences and Center for NanoScience, Ludwig-Maximilians-Universität, Theresienstrasse 41, 80333 München, Germany.
J Am Chem Soc. 2011 May 25;133(20):7909-15. doi: 10.1021/ja200661s. Epub 2011 May 2.
Self-assembly and surface-mediated reactions of 1,3,5-tris(4-mercaptophenyl)benzene--a three-fold symmetric aromatic trithiol--are studied on Cu(111) by means of scanning tunneling microscopy (STM) under ultrahigh-vacuum (UHV) conditions. In order to reveal the nature of intermolecular bonds and to understand the specific role of the substrate for their formation, these studies were extended to Ag(111). Room-temperature deposition onto either substrate yields densely packed trigonal structures with similar appearance and lattice parameters. Yet, thermal annealing reveals distinct differences between both substrates: on Cu(111) moderate annealing temperatures (~150 °C) already drive the emergence of two different porous networks, whereas on Ag(111) higher annealing temperatures (up to ~300 °C) were required to induce structural changes. In the latter case only disordered structures with characteristic dimers were observed. These differences are rationalized by the contribution of the adatom gas on Cu(111) to the formation of metal-coordination bonds. Density functional theory (DFT) methods were applied to identify intermolecular bonds in both cases by means of their bond distances and geometries.
通过在超高真空（UHV）条件下使用扫描隧道显微镜（STM），研究了 1,3,5-三（4-巯基苯基）苯 - 一种三倍对称的芳香三硫醇 - 在 Cu(111) 上的自组装和表面介导反应。为了揭示分子间键的性质，并了解底物在其形成中的特定作用，这些研究扩展到了 Ag(111)。在室温下沉积到任一基底上，都会得到具有相似外观和晶格参数的密集堆积的三角结构。然而，热退火揭示了两个基底之间的明显差异：在 Cu(111)上，适度的退火温度（150°C）已经促使两种不同的多孔网络的出现，而在 Ag(111)上，需要更高的退火温度（高达300°C）才能诱导结构变化。在后一种情况下，只观察到具有特征二聚体的无序结构。这些差异可以通过 Cu(111)上的吸附原子气体对金属配位键形成的贡献来合理化。通过它们的键距离和几何形状，应用密度泛函理论（DFT）方法来确定两种情况下的分子间键。
