Dresden 2026 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 9: Organic molecules on inorganic substrates: electronic, optical and other properties I
O 9.11: Vortrag
Montag, 9. März 2026, 17:30–17:45, HSZ/0201
Intramolecular cyclization of helicenes towards non-benzenoid nanographenes via formation of radicals — •Daniel Rothhardt1, Ming-Lun Pan2, Christian Wäckerlin3,4, Hans Josef Hug1, Yao-Ting Wu2, Karl-Heinz Ernst1,5,6, and Miloš Baljozović1 — 1Empa, Dübendorf, Switzerland — 2National Cheng Kung University, Tainan, Taiwan — 3PSI, Villigen PSI, Switzerland — 4EPFL, Lausanne, Switzerland — 5The Czech Academy of Sciences, Prague, Czech Republic — 6University of Zurich, Zurich, Switzerland
On-surface synthesis has recently become a leading tool for controllable C-C bond formation that would otherwise hardly be accessible by conventional solution chemistry. The advancement of on-surface synthesis gave rise to a novel class of magnetic materials, namely open-shell magnetic nanographenes. The magnetism here mostly stems from the formation of unpaired electrons (radicals) due to a sublattice imbalance, topological frustration or aromatic stabilization. Such carbon-based spin systems are often considered promising candidates for spintronics applications due to their weak spin-orbit coupling and hyperfine interaction, allowing for long spin-lifetime and spin diffusion lengths. Here we demonstrate that the radical formation within the non-planar hydrocarbons such as helicenes leads to intramolecular bond formation and reorganization on Au(111) substrate resulting in non-benzenoid nanographenes. The products are identified using ToF-SIMS, STM and nc-AFM, corroborating the proposed radical-induced cyclization mechanism.
Keywords: On-surface synthesis; nc-AFM; nanographenes; helicenes; Radical-based on-surface chemistry