Intermolecular Interactions, Proton Transfer, and Adatom Rearrangement during Cysteine Dimer Adsorption on Au(111)
Year: 2026
Type: preprint
Abstract: On nanostructured gold, the binding site of a cysteine dimer can move as it adsorbs. The consequences for intermolecular interactions, proton transfer, and the structure of the surface remain unclear. Here, we investigate cysteine dimers on Au(111) substrates with different adatom arrangements using density functional theory optimizations and Born-Oppenheimer molecular dynamics. The resulting trajectories show that adsorption can bring separated adatoms together into compact or extended structures, while other configurations split an existing adatom pair. These outcomes vary with the initial cysteine motif and intermolecular orientation. Deprotonated mercapto groups in thiolate and unconventional zwitterionic motifs bind directly to adatoms, whereas neutral thiols interact more with the underlying surface and can undergo proton transfer near the defects. COOH · · · COOH contacts persist in many thiolate and unconventional zwitterionic pairs, while other initial contacts rearrange or disappear. In thiolate
Source: ChemRxiv
Authors: Aishat Idris, Irina Paci
Language: English
Subfield: Physical and Theoretical Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7221680413