Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 52: Organic/bio Molecules on Metal Surfaces V
O 52.1: Talk
Wednesday, March 13, 2013, 16:00–16:15, H38
Steering on-surface self-assembly of high-quality hydrocarbon networks with terminal alkynes — •Nenad Kepčija1, Yi-Qi Zhang1, Martin Kleinschrodt1, Jonas Björk2, Svetlana Klyatskaya3, Florian Klappenberger1, Mario Ruben3,4, and Johannes V. Barth1 — 1Physik Department E20, Technische Universität München, James-Franck-Straße, 85748 Garching, Germany — 2Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden — 3Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen — 4IPCMS-CNRS, Universite de Strasbourg, 23 Rue de Loess, 67034 Strasbourg, France
The 2D self-assembly of 1,3,5-triethynyl-benzene (TEB) and de novo synthesized 1,3,5-tris-(4-ethynylphenyl)benzene (Ext-TEB) on Ag(111) was studied by means of scanning tunneling microscopy (STM) under ultra-high vacuum (UHV) conditions. Both molecules form nanoporous networks exhibiting organizational chirality, mediated by novel, planar six-fold cyclic binding motifs. Comparison with bulk structures of similar molecules suggests that these motifs appear only in 2D environments. The key interaction is identified as C–H⋯π bonding. For Ext-TEB an additional open-porous phase exists. The nature of the underlying non-covalent bonding schemes is analyzed by the density functional theory (DFT) calculations. Comparison of the calculations focusing on isolated 2D molecular sheets and those including the substrate reveals the delicate balance between molecule-molecule and molecule-substrate interactions.