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

The adsorption of organic chiral molecules on metallic substrates is widely studied as a tool to obtain chiral surfaces. The chirality transfer from the molecules to the surface is strongly driven by the availability of hydrogen atoms, which guides a specific chiral self-assembled structure. In this paper we report, by combination of photoelectron spectroscopy, low-energy electron diffraction, and density functional theory calculations, on the adsorption of the D-enantiomer of alaninol on Cu(100) and on Cu(110) with the aim of revealing dehydrogenation in the formation of the molecular chiral superstructure. We show that, on both surfaces, at low coverage alaninol is dehydrogenated at the hydroxyl group, whereas at saturated coverage the substrate symmetry, in combination with intermolecular interactions, induces partial amino group dehydrogenation on Cu(100) or inhibits hydroxyl group dehydrogenation on Cu(110).