title: Supramolecular organization and chiral resolution of p-terphenyl-m-dicarbonitrile on the Ag(111) surface.
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 pi-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.
authors.affiliation: Physik Department E20, TU München, James-Franck Str, 85748 Garching, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Marschall
authors.forename: Joachim
authors.initials: J
authors.lastname: Reichert
authors.forename: Knud
authors.initials: K
authors.lastname: Seufert
authors.forename: Willi
authors.initials: W
authors.lastname: Auwärter
authors.forename: Florian
authors.initials: F
authors.lastname: Klappenberger
authors.forename: Alexander
authors.initials: A
authors.lastname: Weber-Bargioni
authors.forename: Svetlana
authors.initials: S
authors.lastname: Klyatskaya
authors.forename: Giorgio
authors.initials: G
authors.lastname: Zoppellaro
authors.forename: Alexei
authors.initials: A
authors.lastname: Nefedov
authors.forename: Thomas
authors.initials: T
authors.lastname: Strunskus
authors.forename: Christof
authors.initials: C
authors.lastname: Wöll
authors.forename: Mario
authors.initials: M
authors.lastname: Ruben
authors.forename: Johannes V
authors.initials: JV
authors.lastname: Barth
mesh_terms: D046911:Macromolecular Substances / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013499:Surface Properties; D013730:Terphenyl Compounds / Q000737:chemistry*
chemical_list: D046911:Macromolecular Substances; D013730:Terphenyl Compounds; C551237:p-terphenyl-m-dicarbonitrile; D012834:Silver