Akademik Veri Yönetim Sistemi
Monatshefte fur Chemie, cilt.156, sa.6, ss.631-636, 2025 (SCI-Expanded)
In this work, a new compound, 1-(3,5-dimethoxybenzyl)-5,6-dimethylbenzimidazole, was prepared by N-alkylation of 5,6-dimethylbenzimidazole with potassium hydroxide and 3,5-dimethoxybenzyl bromide in ethanol. Three 5,6-dimethylbenzimidazolium salts were obtained by quaternisation of 1-(3,5-dimethoxybenzyl)-5,6-dimethylbenzimidazole with 4-cyanobenzyl bromide, 4-tert-butylbenzyl bromide, and bromoethane, respectively. Deprotonation of these with silver oxide afforded NHC silver complexes in good yields. The formation of the compounds was validated by nuclear magnetic resonance, Fourier transform infrared spectroscopy, elemental analysis, and LC–MS/MS (only for the silver complexes) methods. The complexes were found to be stable against air and light by 1H NMR analysis of their solutions after one week. Experimental studies were carried out on the antibacterial properties of both benzimidazolium salts and NHC silver complexes against pathogenic strains of Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Enterobacter cloacae. Inhibition zone and minimum inhibitory concentration values were determined. On the basis of these data, it was concluded that all the compounds studied were antibacterial against all the bacterial chains tested, particularly Gram-positive bacteria. The MIC values indicate that the coordination of the NHC ligands to the Ag(I) ion leads to an increase in their antibacterial activity. Bromo[1-(3,5-dimethoxybenzyl)-3-(4-tert-butylbenzyl)-5,6-dimethylbenzimidazolin-2-ylidene]silver showed better activity against S. aureus than the standard antibiotic gentamicin.