Dresden 2011 – scientific programme
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O: Fachverband Oberflächenphysik
O 40: Metal substrates: Adsorption of organic / bio molecules V
O 40.2: Talk
Wednesday, March 16, 2011, 11:30–11:45, PHY C213
Metalation of tetrapyridylporphyrin with Cu atoms on Au(111): aspects of structure and reactivity — •Jie Xiao1, Martin Schmid1, Min Chen1, Ziliang Shi2, Nian Lin2, Tatyana Shubina3, Timothy Clark3, Hans-Peter Steinrück1, and Michael Gottfried1 — 1Universität Erlangen-Nürnberg, Lehrstuhl für Physikalische Chemie II, Erlangen, Germany — 2Hong Kong University of Science and Technology, Hong Kong, China — 3Universität Erlangen-Nürnberg, Computer-Chemie-Centrum, Erlangen, Germany
The reaction between a submonolayer of tetrapyridylporphyrin (2HTPyP) on Au(111) and co-deposited Cu atoms was studied by temperature-dependent X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). The Cu atoms undergo two simultaneous reactions with 2HTPyP: (1) Metalation of the porphyrin core and (2) coordination by pairs of pyridyl groups of adjacent 2HTPyP molecules. At 300 K, the metalation reaction (1) leads mainly to a metastable initial complex, Cu-2HTPyP, in which Cu remains in the zero oxidation state. At elevated temperatures, Cu is oxidized by the porphyrin ligand, forming copper(II) tetrapyridylporphyrin (CuTPyP). Further details of the complex reaction mechanism are revealed by DFT calculations. The coordination reaction (2) leads to the formation of a 2D metal-organic coordination network, which gradually degrades at higher temperatures due to bulk diffusion of Cu, resulting in close-packed molecular monolayer stabilized by intermolecular hydrogen bonds. Supported by the Deutsche Forschungsgemeinschaft through SFB 583 and by the Alexander von Humboldt Foundation.