Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 36: Posters: Bio/organic Molecules on Surfaces, Graphene, Solid/liquid interfaces, Metal Substrates, Electronic Structure Theory

O 36.1: Poster

Dienstag, 1. April 2014, 18:30–22:00, P1

Coverage-dependent metalation and dehydrogenation of tetraphenylporphyrin on Cu(111) — •Michael Röckert, Matthias Franke, Quratulain Tariq, Michael Stark, Stefanie Ditze, Hubertus Marbach, Hans-Peter Steinrück, and Ole Lytken — Lehrstuhl für Physikalische Chemie II and Interdisciplinary Center for Molecular Materials (ICMM), Universität Erlangen-Nürnberg, 91058 Erlangen, Egerlandstraße 3, Germany

The coverage-dependent metalation and dehydrogenation of tetraphenylporphyrin (TPP) on Cu(111) was investigated with XPS, STM and TPD under UHV conditions. 2HTPP has two distinct adsorption structures on Cu(111) [1]: At low coverages (<0.36 molecules/nm²) 2HTPP adsorbs in a disordered structure, but as the coverage is increased a checkerboard-like structure is formed and saturates at 0.55 molecules/nm². As 2HTPP layers on Cu(111) are heated, three distinct reactions take place: metalation, resulting in CuTPP, a partial dehydrogenation of the outer porphyrin-sphere, linking most likely the pyrrole and phenyl rings together, and upon further heating complete dehydrogenation [2]. The two first reactions, metalation and partial dehydrogenation, strongly depend on the structure of the 2HTPP layer. At low coverages, the temperatures for both processes are very close to each other, while at higher coverages metalation shifts down and dehydrogenation up in temperature.

[1] Stark, M. et al. Langmuir 2013, 29, 4104-4110. [2] Xiao, J.; Ditze, S. et al. J. Phys. Chem. C 2012, 116, 12275-12282.