SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 66: Poster: Scanning Probe Microscopy with Quartz Sensors

O 66.8: Poster

Mittwoch, 29. März 2023, 18:00–20:00, P2/EG

On-Surface Synthesis of C144 Hexagonal Coronoid with Zigzag Edges — •Xujie Zhu, Yanan Liu, Weiwen Pu, Fang-Zi Liu, Zhijie Xue, Zhaoru Sun, Kaking Yan, and Ping Yu — School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China

Coronoids as polycyclic aromatic macrocycles enclosing a cavity and they can be also regarded as nanoporous graphene molecules whose electronic properties are critically dependent on the size and topology of their outer and inner peripheries. However, because of their synthetic and characteristic challenges, the extended hexagonal coronoids with zigzag outer edges have not been reported yet. Here, we report the on-surface synthesis of C144 hexagonal coronoid with outer zigzag edges on a designed precursor undergoing hierarchical Ullmann coupling and cyclodehydrogenation on the Au(111) surface. The chemical and electronic structure is unambiguously characterized by bond-resolved non-contact atomic force microscopy and scanning tunneling spectroscopy measurements. In combination with the density functional theory calculations, the result is shown that the HOMO-LUMO energy gap oscillates with the size of the central cavity. Moreover, the values of the harmonic oscillator model of aromaticity suggest that the molecular structure is ideally represented by Clars model. Our results provide approaches toward realizing a hexagonal coronoid with zigzag edges, potentially inspiring fabrication of hexagonal zigzag coronoids with multiple radical characters in the future.