Novel benzimidazol-2-ylidene carbene precursors and their silver(I) complexes: Potential antimicrobial agents.

Novel benzimidazolium salts were synthesized as N-heterocyclic carbene (NHC) precursors, these NHC precursors were metallated with Ag2O in dichloromethane at room temperature to give novel silver(I)-NHC complexes. Structures of these benzimidazolium salts and silver(I)-NHC complexes were characterized on the basis of elemental analysis, (1)H NMR, (13)C NMR, IR and LC-MS spectroscopic techniques. A series of benzimidazolium salts and silver(I)-NHC complexes were tested against standard bacterial strains: Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and the fungal strains: Candida albicans and Candida tropicalis.

N-Heterocyclic carbene-palladium catalysts for the direct arylation of pyrrole derivatives with aryl chlorides.

New Pd-NHC complexes have been synthesized and employed for palladium-catalyzed direct arylation of pyrrole derivatives by using electron-deficient aryl chlorides as coupling partners. The desired coupling products were obtained in moderate to good yields by using 1 mol % of these air-stable palladium complexes. This is an advantage compared to the procedures employing air-sensitive phosphines, which have been previously shown to promote the coupling of aryl chlorides with heteroarenes.