Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 89: Metal substrates: Adsorption of organic / bio molecules V
O 89.1: Vortrag
Freitag, 30. März 2012, 10:30–10:45, A 053
Self-assembly and 2D spontaneous resolution of cyano-functionalized [7] helicenes on Cu(111) — •Tuan Anh Pham1, Serpil Boz2, Aneliia Shchyrba2, Sylwia Nowakowska2, Michael Schär3, François Diederich3, Manh-Thuong Nguyen4, Daniele Passerone4, Thomas Jung5, and Meike Stöhr1 — 1University of Groningen, Netherlands — 2University of Basel, Switzerland — 3ETH Zürich, Switzerland — 4EMPA, Switzerland — 5PSI, Switzerland
Supramolecular control involves the selective recognition of chirality for any target assembly in order to shape e.g. the active elements within their environment. This refers equally to 3D crystal growth as well as to the field of surface-supported supramolecular assemblies. Notably, the spontaneous resolution of racemic compounds into separate enantiomeric crystals serves as an indicator for the enantioselective assembly governed by the specific intermolecular and - for surface supported assemblies - by molecule substrate interactions which can be considered as a complicating factor. Herein, we show the first example of a spontaneous chiral resolution of a helicene derivative on a Cu surface. Through STM and DFT investigations, the formation of fully segregated domains of pure enantiomers (2D conglomerate) from racemic dicyano[7]helicene were demonstrated. The propensity of the system to optimize intermolecular hydrogen bonding as well as dipolar interactions translates into chiral recognition. In addition, a discussion of the effect of chirality on the nucleation and formation of helicene chains for low coverage shall be presented.