Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 65: Poster: Molecular Nanostructures on Surfaces
O 65.4: Poster
Mittwoch, 20. März 2024, 18:00–20:00, Poster C
On-surface reactions of functionalized p-terphenyl on Cu(111): kinetics of the single reaction steps involved — •Mohit Jain1, Tamam Bohamud1, Daniel Kohrs2, Nathaniel Ukah2, Hermann A. Wegner2, and Michael Dürr1 — 1Institut für Angewandte Physik and Zentrum für Materialforschung, Justus-Liebig-Universität Giessen, Germany — 2Institut für Organische Chemie and Zentrum für Materialforschung, Justus-Liebig-Universität Giessen, Germany
For the commonly employed coupling types in on-surface synthesis, the different intermediates formed in the course of the reactions have been investigated in great detail over the recent years. For this, the intermediates are typically induced at variable surface temperatures and are then analysed at low temperature.
In contrast to this, we study the kinetics of the on-surface reaction of 3,3"-dibromo-p-terphenyl on Cu(111) when following the reaction at constant temperature (300 K) with time. Whereas the intermediates are first dominated by long, chain-like structures, they reorganize with increasing time into small 3-membered ring structures. The process includes, a.o., breakage and formation of the involved metal-organic complexes, but trans-to-cis isomerization of the two conformers on the surface was observed to be the slowest reaction step. An almost complete phase change from a mixed phase of chain- and ring-like structures to a phase of regularly oriented, 3-membered ring structures was thus observed only on longer time scales.
Keywords: reaction kinetics; Ullmann coupling; p-terphenyl; Cu(111); scanning tunneling microscopy