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O: Fachverband Oberflächenphysik
O 5: Organic Molecules at Surfaces 1: Substrate Effects
O 5.6: Talk
Monday, September 5, 2022, 12:00–12:15, S051
Tuning of structure of cyano-porphyrin self-assemblies on surfaces: from metals to bulk insulators — Maximilian Ammon1, Mirunalini Devarajulu1, Yi Liu1, Martin Gurrath2, Dominik Lungerich3, •Binbin Da1, Norbert Jux3, Bernd Meyer2, and Sabine Maier1 — 1Department of Physics, FAU Erlangen-Nürnberg, Erlangen, Germany. — 2Interdisciplinary Center for Molecular Materials and Computer Chemistry Center, FAU Erlangen-Nürnberg, Erlangen, Germany. — 3Lehrstuhl für Organische Chemie II, FAU Erlangen-Nürnberg, Erlangen, Germany.
We discuss the adsorption and binding motifs in self-assembled Zn-pCNTPP networks on Au(111), KBr(001), and MgO(001) using low-temperature STM and nc-AFM combined with DFT. Zn-CNTPPs adopt a planar adsorption geometry with the macrocycle parallel to the surface on all three surfaces and assemble in well-ordered islands. While a global minimum structure is found on KBr due to a strong CN⋯K interaction, multiple and energetically nearly equivalent adsorption sites occur on MgO and Au. Therefore, commensurate adsorption is suggested on KBr, while optimizing the molecule-molecule interactions over molecule-surface interactions is more important on MgO and Au, which the STM and nc-AFM data experimentally evidence.[1] However, since the interaction of porphyrins with Au(111) is stronger than on MgO(001), the phenyl rings are more inclined toward the surface, resulting in larger unit cells on Au(111) and also the binding motif of the cyanophenyl groups changes.
[1] Ammon, M. et al., Surface Science, 723, 122097, 2022.