Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 20: Inorganic/Organic Interfaces: Growth III

O 20.6: Talk

Tuesday, March 17, 2015, 11:45–12:00, MA 005

Steering molecular self-assembly of biphenyl-dicarboxylic acid on Cu(111) by tuning the carboxylic hydrogen content — •Tobias Schmitt, Lutz Hammer, and M.Alexander Schneider — Solid State Physics, Univ. Erlangen-Nürnberg, 91058 Erlangen, Germany

Molecular self-assembly is mainly controlled by a complex interplay between molecule-substrate interaction and intermolecular interactions such as hydrogen bonding. We report on the ordered phases of 4,4'-biphenyl-dicarboxylic acid (BDA) on Cu(111) using low temperature scanning tunneling microscopy in ultra-high vacuum. We deposit the molecules at various temperatures to introduce different degrees of thermally activated deprotonation. This leads to different (locally) ordered supramolecular structures. In the case of non-deprotonated BDA head-to-tail coupling between carboxylic groups dominates due to H-bond formation. This mechanism is observed also in semi-deprotonated structures. Fully deprotonated carboxylic groups, in contrast, form chevron-like structures by the interplay of intermolecular carboxylate-aromatic ring hydrogen bonds and carboxylate-copper interaction.