Bowl Inversion of Surface-Adsorbed Sumanene
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- 作者：Rached Jaafar ; Carlo A. Pignedoli ; Giovanni Bussi ; Kamel A茂t-Mansour ; Oliver Groening ; Toru Amaya ; Toshikazu Hirao ; Roman Fasel ; Pascal Ruffieux
- 刊名：Journal of the American Chemical Society
- 出版年：2014
- 出版时间：October 1, 2014
- 年：2014
- 卷：136
- 期：39
- 页码：13666-13671
- 全文大小：489K
- ISSN：1520-5126
文摘
Bowl-shaped 蟺-conjugated compounds offer the possibility to study curvature-dependent host鈥揼uest interactions and chemical reactivity in ideal model systems. For surface-adsorbed 蟺 bowls, however, only conformations with the bowl opening pointing away from the surface have been observed so far. Here we show for sumanene on Ag(111) that both bowl-up and bowl-down conformations can be stabilized. Analysis of the molecular layer as a function of coverage reveals an unprecedented structural phase transition involving a bowl inversion of one-third of the molecules. On the basis of scanning tunneling microscopy (STM) and complementary atomistic simulations, we develop a model that describes the observed phase transition in terms of a subtle interplay between inversion-dependent adsorption energies and intermolecular interactions. In addition, we explore the coexisting bowl-up and -down conformations with respect to host鈥揼uest binding of methane. STM reveals a clear energetic preference for methane binding to the concave face of sumanene.