Lecture
Van Marum Colloquium: Molecular Synthesis Enabled by Surfaces
- Dr. Sabine Wenzel (University of Marburg)
- Date
- Thursday 27 March 2025
- Time
- Location
-
Gorlaeus Building
Einsteinweg 55
2333 CC Leiden - Room
- CM.3.23
Abstract
In recent years, on-surface synthesis has enabled the preparation and study of a variety of carbon-based molecules with tunable structural, (opto-)electronic, and magnetic properties. In the first part, we present the example of the prototypical cycloarene kekulene and its isomer called isokekulene, demonstrating a case of highly selective on-surface synthesis steered by the different faces of single-crystalline copper. Single molecules were identified by scanning tunneling microscopy with CO-functionalized tips, whereas ordered monolayers of the respective products can be characterized by photoemission orbital tomography, a combination of angle-resolved spectroscopy and density functional theory. The results shed light on the aromaticity of molecules and their adsorption geometry. Overall, different molecule-metal interaction strengths can be identified, which lead to the high selectivity.
In the second part, we shift our focus from purely organic synthesis to surface-catalyzed metalation of molecules, reporting the synthesis of one of the first alkali metal porphyrins on a silver surface. Combining X-ray photoelectron spectroscopy and temperature-programmed desorption, an initial dimetallic complex can be identified, which reacts to the product at 400 K. Near-edge X-ray absorption spectroscopy in combination with theory elucidates the geometric structure of the complex and the final product. Both examples add to our understanding of molecular synthesis enabled by surfaces, thereby paving the way for the controlled synthesis of novel compounds.