Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 20: Focus Session: Molecular Nanostructures on Surfaces: On-Surface Synthesis and Single-Molecule Manipulation I
O 20.6: Vortrag
Dienstag, 19. März 2024, 12:00–12:15, HE 101
On-surface Synthesis of Nitrogen-Doped Carbon Nanostructures — •Tim Naumann1, Zilin Ruan1, Olaf Kleykamp1, Alix Kaczmarek2, Eugen Sharikow1, Jörg Sundermeyer1, Doreen Mollenhauer2, and J. Michael Gottfried1 — 1Department of Chemistry, University of Marburg, 35043 Marburg, Germany — 2Department of Chemistry, University of Giessen, 35392 Giessen, Germany
The electronic and magnetic properties of carbon-based nanomaterials can be tailored by altering the topology, introducing defect sites like vacancies, or doping with heteroatoms. Here, we present an on-surface synthesis route to a variety of nitrogen-containing 0D and 1D carbon nanostructures starting from one single precursor. Annealing 4-([1,1'-biphenyl]-2-yl)-2,6-dibromopyridine on Au(111) leads to Ullmann-coupling of the precursor molecules followed by dehydrocyclization to yield cycloarenes with different cavity sizes as well as a nitrogen-doped gulf-edge graphene nanoribbon. Ring formation of six precursor molecules leads to a flat cycloarene, which can host a metal atom in its central cavity. Filling the cavity causes an energetic shift of the cycloarene's frontier orbitals. The direction of the shift depends on the metal used. A curved cycloarene emerges from a ring formed by five precursor molecules, whereas a higher surface coverage favors chain formation. The electronic and geometric properties of the products were investigated by low-temperature scanning tunneling microscopy/spectroscopy (STM/STS) and non-contact atomic force microscopy (nc-AFM).