Institut für Funktionelle Grenzflächen (IFG)

Supramolecular organisation and chiral resolution of p-terphenyl-m-dicarbonitrile molecules on the Ag(111) surface

  • Autor:

    Marschall, M. / Reichert, J. / Seufert, K. / Auwärter, W. / Klappenberger, F. / Weber-Bargioni, A. /Klyatskaya,  S. / Zoppellaro, G. / Nefedov, A. / Strunskus,  T. / Wöll, C. / Ruben, M. / Barth, J. (2010)

  • Quelle: ChemPhysChem 11 (2010), 1446-1451

  • Datum: 2010
  • Marschall, M. / Reichert, J. / Seufert, K. / Auwärter, W. / Klappenberger, F. / Weber-Bargioni, A. /Klyatskaya,  S. / Zoppellaro, G. / Nefedov, A. / Strunskus,  T. / Wöll, C. / Ruben, M. / Barth, J. (2010): „Supramolecular organisation and chiral resolution of p-terphenyl-m-dicarbonitrile molecules on the Ag(111) surface“. In: ChemPhysChem 11 (2010), 1446-1451

Abstract

The supramolecular organization and layer formation of the non-linear, prochiral molecule [1, 1’;4’,1’’]-terphenyl-3,3“-dicarbonitrile adsorbed on the Ag(111) surface is investigated by scanning tunneling microscopy (STM) and near-edge X-ray absorption fine-structure spectroscopy (NEXAFS). Upon two-dimensional confinement the molecules are deconvoluted in three stereoisomers, that is, two mirror-symmetric trans- and one cis-species.

STM measurements reveal large and regular islands following room temperature deposition, whereby NEXAFS confirms a flat adsorption geometry with the electronic p-system parallel to the surface plane. The ordering within the expressed supramolecular arrays reflects a substrate templating effect, steric constraints and the operation of weak lateral interactions mainly originating from the carbonitrile endgroups.

High-resolution data at room temperature reveal enantiormorphic characteristics of the molecular packing schemes in different domains of the arrays, indicative of chiral resolution during the 2D molecular self-assembly process. At submonolayer coverage supramolecular islands coexist with a disordered fluid phase of highly mobile molecules. Following thermal quenching (down to 6 K) we find extended supramolecular ribbons stabilised again by attractive and directional noncovalent interactions, the formation of which reflects a chiral resolution of trans-species.


 

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