Paper SS-ThM3
Chiral Recognition among Non-planar Aromatic Hydrocarbons on Metal Surfaces
Thursday, November 10, 2016, 8:40 am, Room 104D
| Session: |
Chirality and Enantioselectivity on Surfaces; Ionic Liquid Interfaces |
| Presenter: |
Karl-Heinz Ernst, Empa, Swiss Federal Laboratories for Materials Science and Technology, Switzerland |
| Authors: |
A. Mairena, Empa, Swiss Federal Laboratories for Materials Science and Technology
M. Parschau, Empa, Swiss Federal Laboratories for Materials Science and Technology, Switzerland
K.-H. Ernst, Empa, Swiss Federal Laboratories for Materials Science and Technology, Switzerland
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| Correspondent: |
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Molecular recognition among chiral molecules on surfaces is of paramount importance in biomineralization, enantioselective heterogeneous catalysis, and for the separation of chiral molecules into their enantiomers via crystallization or chromatography. Understanding the principles of molecular recognition in general, however, is a difficult task and calls for investigation of appropriate model systems. One popular approach is thereby studying intermolecular interactions on well-defined solid surfaces, which allows in particular the use of scanning tunneling microscopy (STM). We present an elucidation of chiral recognition of helical and bowl-shaped hydrocarbons in monolayers and in multilayers. For penthalicene, a unique coexistence of 2D conglomerate and racemate is observed on a copper surface. Chiral bias in form of small enantiomeric excess leads to single enantiomorphism in multilayered samples of racemic heptahelicene.1 Only the majority enantiomer is allowed to exist in the bottom layer, whereas the top layer consists exclusively of the minority enantiomer, i.e., enantioselective de-wetting occurs. Pentagonal substituted chiral buckybowls form 2D racemate crystals, but chiral hemifullerene restructures a copper surface such that special chiral kinks become stabilized by the enantiomers.2
1 M. Parschau, K.-H. Ernst, Angew. Chem. Int. Ed. 2015, 54, 14422.
2 W. Xiao, K.-H. Ernst et al., Nature Chemistry2016, in press.