Surface Diffusion Aided by a Chirality Change of Self‐Assembled Oligomers under 2D Confinement. (30th September 2022)

• Record Type: Journal Article
• Authors: Bera, Abhijit; Henkel, Stefan; Mieres‐Perez, Joel; Andargie Tsegaw, Yetsedaw; Sanchez‐Garcia, Elsa; Sander, Wolfram; Morgenstern, Karina
• Is Part Of: Angewandte Chemie. Volume 134:Number 43(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-30
• Subjects: 2D Confinement Structure -- Chirality Change -- Diazomethane -- Self-Assembled Oligomer -- Surface Diffusion; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202212245
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Chirality switching of self‐assembled molecular structures is of potential interest for designing functional materials but is restricted by the strong interaction between the embedded molecules. Here, we report on an unusual approach based on reversible chirality changes of self‐assembled oligomers using variable‐temperature scanning tunneling microscopy supported by quantum mechanical calculations. Six functionalized diazomethanes each self‐assemble into chiral wheel‐shaped oligomers on Ag(111). At 130 K, a temperature far lower than expected, the oligomers change their chirality even though the molecules reside in an embedded self‐assembled structure. Each chirality change is accompanied by a slight center‐of‐mass shift. We show how the identical activation energies of the two processes result from the interplay of the chirality change with surface diffusion, findings that open the possibility of implementing various functional materials from self‐assembled supramolecular structures. Abstract : We demonstrate a new functional molecular system with a combination of several advanced features, including a self‐assembled oligomer, surface chirality, chirality switching, and finally their motion on the surface. Our results suggest that nonchiral molecules may be designed to induce switchable enantiomeric surface assemblies, relevant for heterogeneous catalysts.