In vitro antimicrobial studies of new benzimidazolium salts and silver N-heterocyclic carbene complexes

A series of new benzimidazolium salts (1a-g) were synthesized from the reaction of 1-(4-vinylbenzyl) benzimidazole with various alkyl halides. These salts were used to synthesize silver N-heterocyclic carbene (Ag-NHC) complexes (2a-f). The thirteen compounds were characterized by FT-IR, NMR (H-1 and C-13) spectroscopic methods and an elemental analysis technique. These selected candidates were tested for their in vitro antimicrobial activities. Antibacterial and antifungal results indicated that the new salts, and particularly their silver complexes, were found to be strongly effective against seven Gram (-) bacterial strains, three Gram (+) bacterial strains and one yeast (Candida albicans).