Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 7: Focus Session: Functional Molecules at Surfaces I
O 7.3: Talk
Monday, March 16, 2020, 11:00–11:15, TRE Ma
On-surface assembly of supramolecular graphyne-like networks: from hydrogen- and halogen-bonded to organometallic structures — Zechao Yang1, Lukas Fromm2, Tim Sander1, Julian Gebhardt2, Tobias A. Schaub3, Andreas Görling2, Milan Kivala3, and •Sabine Maier1 — 1Department of Physics, FAU Erlangen-Nürnberg — 2Chair of Theoretical Chemistry, FAU Erlangen-Nürnberg — 3Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg
The on-surface assembly of graphyne-like 2D networks is directive for the long-awaited synthesis of the elusive carbon allotrope graphyne. On-surface synthesis facilitates the formation of single-layered materials, however, one of the key issues in the graphyne synthesis is the control of the alkyne coupling reaction. Here, we demonstrate a supramolecular approach to assemble highly-ordered, monolayered hydrogen-/halogen-bonded and organometallic graphyne-like 2D networks from H-/Br-functionalized triethynyltriazine derivatives on Ag(111) and Au(111). The structural and electronic properties of the supramolecular graphynes have been investigated by STM in combination with DFT. We found that intermolecular N⋯Br-C(sp) halogen-bonds − hitherto unexplored in surface-supported self-assemblies − lead to significantly stronger bonded networks compared to N⋯H-C(sp) hydrogen-bonds. After debromination, organometallic networks with Ag/Au-bis-acetylide bonds are formed. The highly-ordered monolayers feature unoccupied electronic states that are delocalized along the networks, which is indicative for a strong reversible bonding.