Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 42: Organic/bio Molecules on Metal Surfaces IV
O 42.11: Vortrag
Mittwoch, 13. März 2013, 13:00–13:15, H38
Control of Intermolecular Bonds by Deposition Rates: Hydrogen Bonds vs. Metal-Coordination in Trinitrile Monolayers — •Thomas Sirtl1,2, Stefan Schlögl1,2, Atena Rastgoo-Lahrood1,2, Jelena Jelic3, Subhadip Neogi4, Michael Schmittel4, Wolfgang M. Heckl1,2,5, Karsten Reuter3, and Markus Lackinger2,5 — 1Department of Physics, Tech. Univ. Munich, James-Franck-Str. 1, 85748 Garching — 2Center for NanoScience (CeNS), Schellingstr. 4, 80799 Munich — 3Department of Chemistry, Tech. Univ. Munich, Lichtenbergstr. 4, 85747 Garching — 4Center of Micro- and Nanochemistry and Engineering, Organische Chemie I, Universität Siegen, Adolf-Reichwein-Str. 2, 57068 Siegen — 5Deutsches Museum, Museumsinsel 1, 80538 Munich (all Germany)
Self-assembled monolayers of a large functional trinitrile molecule are studied on the (111) surfaces of copper and silver by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). A densely packed hydrogen bonded polymorph was equally observed on both surfaces. Additionally, deposition onto Cu(111) yielded a well-ordered metal-coordinated porous polymorph that coexisted with the hydrogen bonded structure. The coordination centers are supplied by the adatom gas of Cu(111). On Ag(111) the metal-coordinated network was never observed. Differences in the adatom reactivity and the resulting bond strength are held responsible for this substrate dependence. By utilizing ultra-low deposition rates, we demonstrate that on Cu(111) adatom kinetics plays a decisive role in the expression of intermolecular bonds - and hence for structure selection.