Modelling Silver Cluster Complexes with the Antibacterial Medication Dioxidine

Abstract

The structures of small silver clusters (Ag_n, n = 1–3, 13) and their complexes with molecules of the antibacterial drug 2,3-bis-(hydroxymethyl)quinoxaline-N,N′-dioxide–dioxidine (Dx) are calculated using the electron density functional method in the DFT/B3LYP5 version. The features of the geometric structure and energy of the metal cluster–dioxidine ligand interaction are considered depending on the size (nuclearity) of the metal cluster. For small clusters (n = 1–3), a tendency for the metal to be coordinated to only one of the oxygen atoms of the ligand molecule is revealed. The most stable complexes are the silver trimers Dx–Ag₃ and the icosahedral silver cluster Dx–Ag₁₃, which are coordinated simultaneously with two oxygen atoms of the hydroxyl groups of the dioxidine molecule. The difference between the obtained optimized structures of the silver–dioxidine complexes and the previously studied silver complexes with hydroxide ligands, for which the hydrogen atom of the ligand hydroxyl group is displaced during the interaction, is shown.