Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 104: Oxides and Insulators: Adsorption I
O 104.6: Vortrag
Donnerstag, 15. März 2018, 18:00–18:15, MA 041
Binding of Isophorone to single Au atoms on MgO(001) and Au(111) — •Niklas Nilius1, Thomas Meyer1, Christian Stiehler1, Karoliina Honkala2, and Hannu Häkkinen2 — 1Institute of Physics, Carl von Ossietzky University, D-26111 Oldenburg, Germany — 2Departments of Physics and Chemistry, Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 Finland
Formation of various metal/organic complexes comprising isophorone (C9H14O) and Au ad-atoms and clusters has been observed on MgO thin films by STM. The aggregates are hold together by electrostatic forces between the hydroxyl groups of the enol-isophorone and negative excess charges residing on the ad-gold. The energetically favorable keto-tautomer, on the other hand, is unreactive towards gold. DFT calculations find a tautomerization barrier between the keto- and enol-form of 0.76 eV on the MgO surface. On Au(111), no tautomerization takes places and isophorone physisorbs in the form of magic clusters containing four, six or nine molecules. Our study demonstrates how tautomerization of an unreactive ketone can be triggered by the presence of low-coordinated and charged metal ad-atoms on an oxide surface.