Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 61: Heterogeneous Catalysis

O 61.8: Poster

Dienstag, 21. März 2017, 18:30–20:30, P2-OG2

Surface assisted synthesis of a porphyrin fragment on Cu(111) and its FM-AFM characterization — •Felix Bischoff, Jacob Ducke, Alexander Riss, Johannes V. Barth, and Willi Auwärter — Physik-Department E20, TUM, James-Franck-Str. 1, 85748 Garching

In-vacuo heterogeneous nano-chemistry bares the potential for creating compounds not achievable with other approaches due to the reactivity of intermediate or final products. For example, the thermal instability of porphyrin fragments such as oligopyrroles often renders them inapplicable for standard UHV preparation techniques. Therefore di- or tripyrrins and related species are scarce in vacuum based surface science and these classes of molecules remain nearly unstudied despite their promising properties as metal-complexing agents in functional organo-metallic compounds or as fluorescent sensors. In this combined low-temperature scanning tunneling microscopy (LT-STM) and frequency modulated atomic force microscopy (FM-AFM) study we will demonstrate the formation of a hitherto unreported porphyrin fragment synthesized through pyrrole cleaving from free-base tetraphenylporphyrins (2H-TPP) on Cu(111). The novel copper metalated tripyrrin derivative is structurally characterized by visualizing its chemical structure via FM-AFM with CO-functionalized tips and via tip manipulations. We will furthermore suggest a possible reaction pathway by identifying reaction intermediates. Additionally, the products of the thermally activated flattening reaction of 2H-TPP on Cu(111) will be structurally determined by FM-AFM.