Regensburg 2016 – scientific programme

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O: Fachverband Oberflächenphysik

O 58: Organic-Inorganic Systems III: Metal-Organics

O 58.11: Talk

Wednesday, March 9, 2016, 17:45–18:00, S054

Surface-assisted reactions of porphyrins investigated by nc-AFM — •Jacob Ducke, Yuanqin He, Felix Bischoff, Manuela Garnica, and Willi Au — TU München, Germany

Surface-assisted covalent linking of precursor molecules enables the fabrication of low-dimensional nanostructures. Here, we present a temperature-induced covalent dehydrogenative coupling mechanism of free-base porphine (2H-P) units. The oligomers resulting from a homocoupling reaction have been characterized by a multitechnique approach and theoretical modelling, however an atomically resolved study of the resulting nanostructures was lacking [1]. With nc-AFM we are able to identify the resulting bonding motifs and can confirm the proposed structural models. Furthermore, we used a similar coupling mechanism to functionalize the edges of epitaxial grown graphene on Ag(111) with 2H-P [2]. Distinct configurations are identified and resolved at the graphene edges with submolecular precision. Functionalization reactions like metallation of the 2H-P and subsequent axial ligation of adducts are conserved for porphines coupled to graphene. Thus, our findings bear promise for functionalized graphene nanostructures and for the formation of tailored oligomeres on surfaces.

[1] Wiengarten, A., et al. "Surface-assisted dehydrogenative homocoupling of porphine molecules." J. Amer. Chem. Soc. 136 (2014): 9346-9354.

[2] He, Y., et al. "Fusing tetrapyrroles to graphene edges by surface-assisted covalent coupling." submitted