Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 75: Organic/bio Molecules on Metal Surfaces VI
O 75.3: Talk
Thursday, March 14, 2013, 16:30–16:45, H38
Temperature-Dependent Chemical and Structural Transformations from 2H-Tetraphenylporphyrin to Copper(II)-Tetraphenylporphyrin on Cu(111) — •Stefanie Ditze, Michael Stark, Jie Xiao, Michael Röckert, Martin Drost, Florian Buchner, Ole Lytken, Hans-Peter Steinrück, and Hubertus Marbach — Lehrstuhl für Physikalische Chemie II and Interdisciplinary Center for Molecular Materials (ICMM), Universität Erlangen-Nürnberg, Egerlandstr. 3, D-91058 Erlangen
Temperature-driven chemical and structural changes of 2H-Tetraphenylporphyrin (2HTPP) adsorbed on Cu(111) have been investigated by a combination of scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) under UHV conditions. The first chemical change is a redox reaction of the porphyrin center with Cu atoms from the substrate, resulting in the formation of Copper(II)-Tetraphenylporphyrin (CuTPP). For a coverage of about 0.17 molecules/nm2, this reaction was found to start around 400 K and can easily be monitored by STM, due the very different adsorption behavior of 2HTPP and CuTPP on Cu(111). The energetic parameters of this self-metalation reaction were determined by isothermal STM experiments.[1] Subsequent annealing to 450 and 500 K leads to two intramolecular structural changes, which are attributed to successive dehydrogenation reactions of CuTPP.[2]
This work has been funded by the DFG through SFB 583.
[1] S. Ditze et al.Angew. Chem. Int. Ed. 2012, 51, 10898-10901 [2] Xiao et al. J. Phys. Chem. C 2012, 116, 12275-12282