Chiral Steering of Molecular Organization in the Limit of Weak Adsorbate−Substrate Interactions: Enantiopure and Racemic Tartaric Acid Domains on Ag(111)

Abstract

The influence of intermolecular interactions involving molecular chiral centers on two-dimensional organization in the limit of a weak adsorbate-surface interaction has been studied with low-temperature scanning tunneling microscopy (STM) and density functional theory (DFT). A model system composed of a chiral organic molecule, tartaric acid, and an inert metallic surface, Ag(111), was employed. Dual component films formed from the serial deposition of (S,S)-and (R,R)-tartaric acid enantiomers onto this surface exhibit homochiral domain formation as revealed by molecularly resolved STM images. In contrast, a unique tartaric acid enantiomeric heteropair is experimentally and computationally verified as the basis unit of films formed via the deposition of both enantiomers simultaneously from a racemic (1:1) mixture. The molecular adsorption geometry relative to the Ag(111) lattice in both enantiomerically pure and racemic domains is determined primarily by the interaction of chiral centers between nearest neighbors.

Double‐Helical Nanostructures with Controllable Handedness in Bulk Diblock Copolymers

“…The absence of the helix in the PBd‐ b ‐PEO film loaded with racemic TA can be rationalized in terms of a stronger interaction between the molecules of the racemate than of the enantiomer TA with PEO. The Pearl group previously proved that a racemic heteropair structure had the lowest energy level for the racemic TA pair . On the other hand, in our previous study, the d ‐spacing between two neighboring cylinders in the helical structure was almost the same as that of the racemic‐TA‐doped BCP if a single‐helical structure was formed .…”

Chirality Transfer in 1D Self-Assemblies: Influence of H-Bonding vs Metal Coordination between Dicyano[7]helicene Enantiomers

“…Aneliia Shchyrba, 1 Manh-Thuong Nguyen, 2 Christian Wäckerlin, 3 Susanne Martens, 1 Sylwia Nowakowska, 1 Toni Ivas, 1 Jesse Roose, 4 Thomas Nijs, 1 Michael Schär, 4 Meike Stöhr, 5 Carlo A. Pignedoli, 6 Carlo Thilgen, 4 François Diederich, 4 Daniele Passerone, 6 and Thomas A. Jung.…”

“…2,3 Recently, a Pasteur type 4 spontaneous chiral resolution has been shown to occur also in two dimensions, at surfaces. 2,[5][6][7] In analogy to the 3D case, the condensation of 2D islands at surfaces can be controlled by the enantiomeric excess 8,9 of one component or by a chiral auxiliary. 10 Chirality transfer and the long-range expression of chirality in molecular self-assembly have been studied intensively in surface science.…”

Double‐Helical Nanostructures with Controllable Handedness in Bulk Diblock Copolymers

“…Thea bsence of the helix in the PBd-b-PEO film loaded with racemic TA can be rationalized in terms of as tronger interaction between the molecules of the racemate than of the enantiomer TA with PEO.T he Pearl group previously proved that ar acemic heteropair structure had the lowest energy level for the racemic TA pair. [9] On the other hand, in our previous study, the d-spacing between two neighboring cylinders in the helical structure was almost the same as that of the racemic-TA-doped BCP if as ingle-helical structure was formed. [7b] Considering the size of the helical structure,adoublestranded helical model is assumed for the samples investigated in this study.Asanimportant parameter,the pitch of the helical nanostructure was calculated for the structures observed by TEM ( Figure 3a,b and Figure S4).…”