Dresden 2014 – scientific programme

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O: Fachverband Oberflächenphysik

O 77: Focussed Session: Towards a Quantitative Understanding of Complex Adsorption Structures: Surface Science goes Organic III

O 77.10: Talk

Thursday, April 3, 2014, 18:30–18:45, TRE Phy

Structure-dependent reactions of tetraphenylporphyrin with Cu(111) — •Ole Lytken, Michael Röckert, Matthias Franke, Quratulain Tariq, Michael Stark, Stefanie Ditze, Hubertus Marbach, and Hans-Peter Steinrück — Lehrstuhl für Physikalische Chemie II, Universität Erlangen-Nürnberg, 91058 Erlangen, Egerlandstraße 3, Germany

As tetraphenylporphyrin (2HTPP) is deposited on Cu(111) and heated, several distinct reactions happen: First the porphyrin molecule picks up a copper atom from the surface and metalates forming copper(II)tetraphenylporphyrin (CuTPP), which subsequently dehydrogenates, first loosing 8 hydrogen atoms and later the remaining 20. The first dehydrogenation reaction is proposed to link the phenyl rings with the pyrrole rings, and the last dehydrogenation reaction is proposed to be the loss of the remaining hydrogen atoms producing an ill-defined, interlinked, nitrogen-doped carbon network on the surface. The rate of the metalation and the first dehydrogenation both depends strongly on coverage, with an abrupt change as the coverage is increased and the structure of the adsorbed 2HTPP layer changes. Using XPS, STM and TPD (of both deuterated and undeuterated molecules) the reaction rates and the different intermediates on the surface have been investigated in the temperature range from 200-1000 K as a function of the structure of the initial 2HTPP layer.