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O: Fachverband Oberflächenphysik
O 69: Nanostructures at Surfaces II
O 69.6: Vortrag
Mittwoch, 19. März 2025, 16:15–16:30, H25
Pyridyl-functionalized tripod molecules on Au(111): Inter-play between hydrogen bonding and metal coordination — •Sajjan Mohammad1, Neeta Bisht2, Anjana Kannan1, Anne Brandmeier2, Christian Neiss2, Andreas Görling2, Meike Stöhr1,3, and Sabine Maier1 — 1Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany — 2Department of Chemistry and Pharmacy, Chair of Theoretical Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany — 3University of Applied Sciences of the Grisons, Switzerland
Two-dimensional metal-organic coordination networks (MOCNs) offer rich opportunities for fabricating materials with potential applications in catalysis and molecular electronics. We investigated the self-assembly of pyridyl-functionalized triazine (T4PT) on Au(111) using low-temperature scanning tunneling microscopy (STM) complemented by density functional theory (DFT) calculations. T4PT forms a well-ordered, close-packed structure stabilized by hydrogen bonds upon adsorption at 300 K. Upon post-deposition annealing, the assemblies are additionally stabilized by metal-ligand bonding between the pyridyl ligands and native Au adatoms. Further post-deposition annealing to 473 K led to the breaking of the N-Au bonds, with the molecular assemblies transforming into a second close-packed hydrogen-bonded structure. Above 503 K, few covalently linked dimers formed, likely as a result of CH-bond activation. Our findings highlight the challenge of predicting and controlling 2D structure formation for porous MOCNs on metal surfaces due to competing interactions.
Keywords: scanning tunneling microscopy; molecular self-assembly; metal coordination; hydrogen-bonding