Bowl-shaped π-conjugated compounds offer the possibility to study curvature-dependent host–guest interactions and chemical reactivity in ideal model systems. For surface-adsorbed π 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–guest binding of methane. STM reveals a clear energetic preference for methane binding to the concave face of sumanene.
|Titolo:||Bowl Inversion of Surface-Adsorbed Sumanene|
|Autori:||Jaafar, R.; Pignedoli, C. A.; Bussi, G.; Aït-Mansour, K.; Groening, O.; Amaya, T.; Hirao, T.; Fasel, R.; Ruffieux, P.|
|Data di pubblicazione:||2014|
|Digital Object Identifier (DOI):||10.1021/ja504126z|
|Appare nelle tipologie:||1.1 Journal article|