Berlin 2012 – scientific programme

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DS: Fachverband Dünne Schichten

DS 38: Poster III: Resistive switching (jointly with DF, KR, HL); Thermoelectric materials (Focused session); Micro- and nanopatterning (jointly with O); Ion irradiation effects

DS 38.35: Poster

Thursday, March 29, 2012, 17:30–19:00, Poster E

Nanopatterning by molecular polygons — •Stefan-Sven Jester, Eva Sigmund, and Sigurd Höger — Rheinische Friedrich-Wilhelms-Universität Bonn, Kekulé-Institut für Organische Chemie und Biochemie, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany

Self-assembled monolayers of shape-persistent macrocycles at the solid/liquid interface (here: 1,2,4-trichlorobenzene/HOPG) are investigated by scanning tunneling microscopy. The macrocycles are accessible from cyclooligomerization of the respective half-rings and subsequent separation of the respective crude product. The chemical structure includes dithiophene corner units connected via linear phenylene-ethynylene-butadiynylene rod units. The resulting cyclooligomers (of oligomerization degree n = 3-6) can be viewed as equilateral two-dimensional polygons with three to six sides and diameters in the range of 2-5 nm. The distinct shapes allow the formation of predictable surface patterns with lateral periodicities of up to 19 nm. The results include the 2D crystallization of molecular pentagons as well as the formation of binary mixtures of triangles and hexagons and thus provide an insight into how the symmetry of molecules is translated into periodic structures. [1] S.-S. Jester, E. Sigmund, S. Höger, J. Am. Chem. Soc. 2011, 133, 11062.