Noncovalent binding phenomena in the adsorption of amino acids on Ag/Au surfaces: a theoretical approach

Adsorption of amino acids (AAs) onto Ag and Au surfaces has attracted much interest in the past years, owing to their ability to control and tune the structure of Ag and Au nanoparticles (NPs) during the synthetic procedure and to enhance their stability under various conditions. Despite this, the molecular recognition events that are responsible for such stabilization as well as the role of the AA residue moieties is still not completely understood. To tackle this point, we computationally evaluated the weak interactions involved in the AA⋯Ag/AuNP recognition process from a theoretical perspective. In more detail, we analysed the strength and physical nature of the interactions established between twenty essential AAs and Ag/AuNPs at the PBE0-D3/def2-TZVP level of theory. The structural and energetic studies were complemented by the use of the quantum theory of atoms in molecules (QTAIM), non-covalent interaction plot (NCIplot) and energy decomposition analysis (EDA) techniques, providing new insights into the nature and spatial extension of the interactions studied herein. We believe that the results reported in this exploratory study will be useful for researchers working in the fields of bioinorganic chemistry, biotechnology and supramolecular chemistry by shedding light on the weak binding phenomena that are crucial for achieving AA⋯Ag/AuNP recognition.