Berlin 2024 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 39: Poster: Metal Substrates
O 39.7: Poster
Dienstag, 19. März 2024, 18:00–20:00, Poster D
On-surface reactions of triazido-s-heptazine — •Ilias Gazizullin1, Christophe Nacci1, Friedrich Esch2, and Leonhard Grill1 — 1Physical Chemistry Department, University of Graz, Austria — 2Faculty of Chemistry, TU München, Germany
2,5,8-Triazido-s-heptazine is an aromatic molecule containing only carbon and nitrogen atoms. Heptazine core functionalized with reactive azido-groups makes it an interesting candidate as a precursor for on-surface synthesis of graphitic carbon nitride, an important 2D material [1]. The challenge in this approach is that there are several alternative reaction pathways, which are difficult to control, due to the high reactivity of the aromatic azides [2].
Here, we study these molecules by low temperature scanning tunneling microscopy (STM) under ultra-high vacuum conditions, which allows to study changes in single molecules induced by different impacts. Molecular transformations are induced either by voltage pulses from the STM tip or by illumination with UV light. In each case, we observe two types of processes. Short illumination or short voltage pulse induce dissociation of the azido-group into a molecular nitrogen and a nitrene molecule. On the other hand, longer illumination times lead to drastic increase of the apparent height, which will be discussed in view of other options, for instance the formation of another product or different adsorption configurations.
[1] Krinninger et al., Chem. Mater., 35, 17, 6762 (2023)
[2] Hellerstedt et al., Angewandte Chemie, 58, 2266 (2019)
Keywords: single molecules; STM; photochemistry; azides; tip-induced reactions