Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 36: Poster Session II (Metals; Nanostructures at surfaces; Surface or interface magnetism; Spin-Orbit Interaction at Surfaces; Electron and spin dynamics; Surface dynamics; Methods; Theory and computation of electronic structure)

O 36.13: Poster

Dienstag, 15. März 2011, 18:30–22:00, P4

Surface-confined reaction of porphyrins with Cu atoms: An X-ray photoelectron spectroscopy study — •Min Chen, Martin Schmid, Jie Xiao, Hans-Peter Steinrück, and J.Michael Gottfried — Universität Erlangen-Nürnberg, Lehrstuhl für Physikalische Chemie II, Erlangen, Germany

Porphyrin derivatives are wide-spread in nature and of considerable technological importance as candidates for the construction of functional devices. Examples are the usage of metalloporphyrins and similar macrocycles as organic semiconductors or for the functionalization of surfaces in catalysis or sensor applications. As shown previously, free-base porphyrins readily form ordered monolayers on single-crystalline substrates and represent redox-active ligand precursors, which can oxidize and coordinate adsorbed metal atoms. In this study, we focus on the reactivity of various porphyrin derivatives towards adsorbed Cu atoms. As a first model system, we studied the reaction of tetrapyridylporphyrin (2HTPyP) with Cu atoms on Au(111). The co-adsorbed reactants form an intermediate at 300 K, which reacts further to Cu(II) tetrapyridylporphyrin at higher temperatures. If 2HTPyP is deposited on a Cu/Au(111) subsurface alloy, the metalation reaction leads to a segregation of Cu due to the strong Cu-porphyrin bond. Related experiments with tetraphenylporphyrin and phthalocyanine will be discussed. In addition, the above results for Cu atoms on Au(111) will be compared with reactions of porphyrins on Cu(111). Support by the Deutsche Forschungsgemeinschaft through SFB 583 and by the Alexander von Humboldt Foundation is acknowledged.