Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 59: Poster Session II (Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: arrays; Nanostructures at surfaces: Wires, tubes; Nanostructures at surfaces: Other; Plasmonics and nanooptics; Metal substrates: Epitaxy and growth; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsoprtion of organic / bio molecules; Metal substrates: Adsoprtion of inorganic molecules; Metal substrates: Adsoprtion of O and/or H; Metal substrates: Clean surfaces; Density functional theory and beyond for real materials)
O 59.78: Poster
Mittwoch, 24. März 2010, 17:45–20:30, Poster B1
Surface assisted oxidation of flat lying organic molecules - a real-time STM study — •Thomas Waldmann1, Daniela Künzel2, Michael Roos1, Achim Breitruck1, Harry E. Hoster1, Axel Groß2, and R. Jürgen Behm1 — 1Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm, Germany — 2Institute of Theoretical Chemistry, Ulm University, D-89069 Ulm, Germany
Using time resolved scanning tunneling microscopy (STM), we tested the interaction of O2 from gas-phase with ordered adlayers of the Bis(terpyridine) derivative 2,4’-BTP [1,2] on Au(111) [3], Ag(111) [3,4] and graphite (HOPG) [1-3,5] surfaces at T = 300 K. At an O2 pressure of 10−5 mbar, the adlayers on Ag(111) undergo chemical and structural changes. These include modifications of the 2-pyridyl rings of individual 2,4’-BTP adsorbates and rearrangements of the hydrogen bonded adlayer. Since we do not observe similar changes on HOPG and Au(111), we assume that Ag(111) acts as catalyst for the underlying processes. Based on our STM data in combination with DFT calculations, we conclude that the observed reaction is pyridyl-N-oxide formation. Furthermore, we derive reaction yields, enantiomeric excess, reaction rates and reaction orders from the time-resolved STM data.
[1] U. Ziener et al., Chem.Eur.J. 8, 2002, 951.
C. Meier et al., J.Phys.Chem.B 109, 2005, 21015.
H.E. Hoster et al., Langmuir 23, 2007, 11570.
M. Roos et al., Phys.Chem.Chem.Phys. 9, 2007, 5672.
M. Roos et al., Phys.Chem.Chem.Phys., DOI:10.1039/b920481d