Chemical, spectroscopic characterization, DFT studies and antibacterial activities in vitro of a new gold(I) complex with rimantadine

A novel gold(I) complex with rimantadine (RTD) was obtained and structurally characterized by a set of chemical and spectroscopic analysis. 1H, 13C and 15N nuclear magnetic resonance (NMR) and infrared (IR) spectroscopic measurements suggest coordination of the ligand to Au(I) through the N atom of the ethanamine group. Theoretical (DFT) calculations confirmed the IR assignments and permit proposing an optimized geometry for the complex. The gold(I)–rimantadine complex (Au–RTD) is soluble in methanol, ethanol, dimethylsulfoxide, acetone and acetonitrile. The preliminary kinetic studies based on UV–vis spectroscopic measurements indicate the stability of the compound in solution. Antibacterial activities of the complex were evaluated by an antibiogram assay. The Au–RTD complex showed an effective in vitro antibacterial activity against the Pseudomonas aeruginosa, Escherichia coli (Gram-negative), and Staphylococcus aureus (Gram-positive) bacterial strains.

Optimized structure of the gold(I)–rimantadine complex: gold (yellow), carbon (orange), nitrogen (blue) and hydrogen (white).Figure optionsDownload as PowerPoint slideHighlights
► A novel gold(I) complex with rimantadine.
► IR and NMR studies permitted proposing nitrogen coordination of the NH2 group.
► Coordination of cyanide was also confirmed by IR and NMR analyses.
► DFT studies permitted optimization of the structure of the complex.
► The compound shows antibacterial activities against Gram-negative and Gram-positive bacterial strains.