Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Poster Session III (Solid-liquid interfaces; Scanning probe and other methods; Electronic structure theory; Spin-orbit interaction)

O 58.11: Poster

Mittwoch, 13. März 2013, 18:15–21:45, Poster B1

Nanoscale surface patterning by molecular polygons: Can shape-persistent molecules behave like geometric tiles? — •Stefan-S. Jester, Nina Schönfelder, Eva Sigmund, and Sigurd Höger — Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany

Shape-persistent macrocycles are formed by cyclooligomerization of respective acetylene-terminated half-ring structures under oxidative coupling conditions and subsequent separation of the crude product by recycling gel permeation chromatography. Self-assembled monolayers of the resulting monodisperse compounds are investigated by scanning tunneling microscopy at the interface of 1,2,4-trichlorobenzene and highly oriented pyrolytic graphite. The macrocycles (3 ≤ n ≤ 6) can be viewed as equilateral molecular polygons (triangles, squares, pentagons, hexagons) that consist of rigid backbones and long flexible alkoxy side chains. We particularly focus on dithiophene corner units linked by p-phenylene-ethynylene-butadiynylene rods. The length of the latter can be systematically increased, and the related polygon sizes define the pattern periodicities. Cocrystallization - for example after mixing triangles and hexagons - increases the complexity of the resulting patterns. One fundamental question is how and to which extent the concepts of discrete geometry can be transferred to design patterns with unit cells far beyond 20 nm. [1] S.-S. Jester, E. Sigmund, S. Höger, J. Am. Chem. Soc. 2011, 133, 11062.