Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 30: Focussed session: Functional molecules at surfaces I
O 30.4: Vortrag
Dienstag, 27. März 2012, 11:45–12:00, A 053
On-surface covalent linking of organic building blocks on a bulk insulator — Markus Kittelmann1, Philipp Rahe1, Markus Nimmrich1, •Robert Lindner1, André Gourdon2, and Angelika Kühnle1 — 1Institut für Physikalische Chemie, Johannes Gutenberg-Universität Mainz, Germany — 2CNRS, CEMES, Nanoscience Group, 29 Rue J. Marvig, 31055 Toulouse, France
On-surface synthesis in ultra-high vacuum provides a promising strategy for creating thermally and chemically stable molecular structures at surfaces. Very recently, few pivotal experiments have been presented, demonstrating the potential of this concept on metallic substrates.
However, many of the envisioned applications require non-conductive rather than metallic substrates to prevent electronic coupling and leakage or non-radiative quenching. Thus, it becomes exceedingly important to transfer this technique to bulk insulators.
Here, we demonstrate the covalent linking of organic molecules on a bulk insulator, namely calcite. We deliberately employ the strong electrostatic interaction between the carboxylate groups of halide substituted benzoic acids and the surface calcium cations to reach homolytic cleavage temperatures before molecular desorption. This allows for the formation of aryl radicals and intermolecular coupling. By varying number and position of the halide substitution, we rationally design the resulting structures, revealing straight lines, zigzag structures as well as dimers, providing clear evidence for the covalent linking [1].
[1] Kittelmann, M., et al., ACS Nano 2011, 5 (10), 8420-8425