N-functionalized benzimidazol-2-ylidene silver complexes: synthesis, characterization, and antimicrobial studies

2-Methoxyethyl, 2-diethylaminoethyl, and 2-phenylethyl-substituted N-heterocyclic carbene (NHC) precursors were treated with Ag2CO3 to yield silver(I)-NHC complexes (1a-g) in dichloromethane as a solvent at room temperature. The 7 new silver-NHC complexes were fully characterized by means of H-1 NMR, C-13 NMR, and elemental analysis techniques. Using the agar dilution procedure recommended by the Laboratory and Clinical Standards Institute, the antimicrobial activities of all the silver-NHC complexes were studied against 2 gram-negative bacterial strains (Pseudomonas aeruginosa and Escherichia coli), 2 gram-positive bacterial strains (Enterococcus faecalis and Staphylococcus aureus), and 2 fungi (Candida tropicalis and Candida albicans).