A silver complex with ibuprofen: Synthesis, solid state characterization, DFT calculations and antibacterial assays

The present work describes the synthesis of a silver(I) complex with the non-steroidal anti-inflammatory ibuprofen, Ag-ibu. Elemental and thermal analyses indicate a 1:1 metal/ligand composition. Thermogravimetric analysis shows that Ag-ibu decomposition starts at 180 °C, and ends at 400 °C (mass loss 64.6%; calcd. 65.5%). UV/Vis kinetic measurements suggest the decomposition of Ag-ibu in dimethyl sulfoxide, with the appearance of a broad band in the spectrum of the complex in the range 300-500 nm. Infrared and solid state 13C NMR spectra show the coordination of ibuprofen to silver through the carboxylate group. The DFT calculations led us to propose a dimeric silver bridging structure for the complex. Biological studies show the antibacterial activity of the Ag-ibu complex against Gram-positive and Gram-negative bacterial strains, with MIC values ranging from 6.25 to 12.5 μg mL−1.