Supramolecular Organization and Chiral Resolution of p-Terphenyl-m-Dicarbonitrile on the Ag(111) Surface

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 π‐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. The supramolecular organization and layer formation of a non‐linear, prochiral molecule adsorbed on the Ag(111) surface is investigated. Upon 2D confinement the molecules are deconvoluted in three stereoisomers. The ordering within the expressed supramolecular arrays reflects a substrate templating effect, steric constraints and the operation of weak lateral interactions (see picture).