Revisiting the conformational adsorption of L‐ and D‐cysteine on Au nanoparticles by Raman spectroscopy

Understanding the physical mechanisms of thiolated molecules adsorption on metal surfaces has required copious research, particularly on Au–cysteine systems due to the affinity of sulfur molecules to gold surfaces, as well as the interesting structural modifications that this strong interaction induces and the peculiar optical, chiroptical, and electronic properties of Au(SR) systems. Here, we present vibrational experimental data on the adsorption of L‐ and D‐cysteine on small gold nanoparticles (2 nm) synthesized L‐ and D‐cysteine capped gold nanoparticles are obtained by means of Raman spectroscopy, confirming a stable conformation for cysteine that locates the carboxyl group in the antiposition for both L‐ and D‐cysteines. Au34 Cys configurations are obtained using DFT‐D3 global optimization random searches in order to explore the preferred cysteine adsorption sites and calculate the Raman spectra. General analysis confirms the cysteine interaction with gold through the carboxyl and thiol groups.