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O: Fachverband Oberflächenphysik
O 65: Poster: Molecular Nanostructures on Surfaces
O 65.3: Poster
Mittwoch, 20. März 2024, 18:00–20:00, Poster C
Synthesis and Characterization of Pentadecacene by Tip-manipulation with a Scanning Probe Microscope — •Grigori Pasko1, Zilin Ruan1, Tim Naumann1, Jakob Schramm2, John Bauer3, Holger F. Bettinger3, Ralf Tonner-Zech2, and J. Michael Gottfried1 — 1University of Marburg, 35043 Marburg, Germany — 2University of Leipzig, 04103 Leipzig, Germany — 3University of Tübingen, 72076 Tübingen, Germany
Carbon nanomaterials exhibit versatile electronic properties that potentially can be exploited in the field of organic semiconductors. The acene series is an interesting class of compounds consisting of linearly fused polycyclic aromatic hydrocarbons (PAHs). The description as a closed-shell system becomes inadequate for long acenes as their (poly-)radical character increases. The resulting enhanced reactivity makes higher acenes hardly accessible for solution chemistry, so that novel synthetic procedures are required. Here, we demonstrate the on-surface synthesis of pentadecacene (15ac), the longest acene known to date, via atom-manipulation-induced C-C-bond dissociation of a trietheno-bridged precursor on the Au(111) surface. Scanning tunneling microscopy/spectroscopy (STM/STS) and atomic force microscopy (AFM) were carried out at temperatures below 5 K to investigate the electronic properties. 15ac has an antiferromagnetic singlet (S=0) ground state characterized by a singlet-triplet gap of 124 meV and a transport gap of 1.11 eV. Spin localization and Kondo-screening was observed for Au-complexes of 15ac with an uneven number of C-Au-bonds which reveals the S=1/2 ground state of such complexes.
Keywords: scanning probe techniques; tip-manipulation; on-surface synthesis; acenes; spin localization