Transfer of chirality from adsorbed chiral molecules to the substrate highlighted by circular dichroism in angle-resolved valence photoelectron spectroscopy

Abstract

The study of self-assembled chiral molecules on achiral metallic surfaces is mostly focused on the determination of the geometry of adsorbates and the related electronic structure. The aim of this paper is to provide direct information on the chirality character of the system and on the chirality transfer from molecules to the substrate by means of circular dichroism in the angular distribution of valence photoelectrons for extended domain of chiral self-assembled molecular structure, formed by alaninol adsorbed on Cu(100). We show that the presence of molecular chiral domains induces chiral electronic states in the interaction with the substrate and locally transfers chiral character to the underneath metal atoms participating in the adsorption process. Identification of chirality in the adsorption footprint represents an important aspect for controlling and tuning the functionality of the molecular-metal interfaces.

Interplay between Supramolecularity and Substrate Symmetry in the Dehydrogenation of d-Alaninol on Cu(100) and Cu(110) Surfaces

“…34 These valence states have been studied using circular dichroism in the angular distribution of photoelectrons to have direct information on the chirality behavior of a chiral surface obtained by self-assembled molecules. 6 A comparison between the valence bands obtained for LC and SC situations shows an increase in the intensity of the structures attributable to D-alaninol. Changes in peak shape will be interpreted with the help of theoretical results.…”

“…Two-dimensional (2D) chiral surfaces obtained functionalizing metal surfaces with chiral molecules are active in biological processes and biomedicine and are of fundamental importance in enantiomeric compound separation, catalysis, and sensors. − Chirality is transferred from molecules to the surface via the formation of self-assembled monolayers, driven by supramolecular effects such as long-range interactions and hydrogen bond network formation. − …”

Reversibility and intermediate steps as key tools for the growth of extended ordered polymers via on-surface synthesis

“…Each observed structure corresponds in a predictable fashion to the geometric and chemical nature of the porphyrin substituents ( Figure 1b) [47]. Among the studies of self-assembly on surfaces, the aspect of chirality has also received increased attention, mainly because of its importance in enantioselective heterogeneous catalysis [48][49][50][51][52][53][54][55]. The use of chiral and prochiral molecules changes the properties of the self-assembled molecular superstructure, both for aggregates and monolayers.…”

Making Glycine Methyl Ester Chiral

“…An alternative to selective photolysis could be chirality transfer from a chiral to an achiral molecule. There are multiple examples for such chirality transfer, such as from solvates to solvents, chiral guests to macromolecular hosts, chiral metal clusters to surface adsorbates, or even from chiral adsorbates to metal surfaces . The investigation of molecular complexes composed of an either ( R )‐ or ( S )‐configured template and an achiral substrate by vibrational circular dichroism (VCD) spectroscopy should allow the identification of chirality transfer by the appearance of a VCD signal that is due to a vibrational normal mode located on the substrate.…”