Novel benzimidazolium salts and their silver(I)-<i>N</i>-heterocyclic carbene complexes: synthesis, characterization and their biological properties

This study was conducted to synthesize and characterize 1,3-dialkyl-5,6-dimethyl-benzimidazolium salts and their silver complexes. Four novel silver(I)-<i>N</i>-heterocyclic carbene complexes were synthesized and characterized by mass analyses, FT-IR and NMR spectroscopy. The biological capacity of the synthesized compounds was evaluated <i>in vitro</i> for their antimicrobial and antitumor activities. The minimum inhibitory concentration (MIC) of the 1,3-dialkyl-5,6-dimethyl-benzimidazolium salts and their complexes was determined for <i>E. coli</i>, <i>P. aeruginosa</i>, <i>S. aureus</i>, <i>C. glabrata</i> and <i>C. albicans in vitro</i> through BMD (Broth Microdilution). The results indicated that silver(I)-NHC complexes exhibit antimicrobial activity. In particular, complex <b>3c</b> presented a significant broad-spectrum antimicrobial activity. The anticancer properties of the synthesized compounds were evaluated against MCF-7, HCT116, SH-SY5Y and BEAS-2B cell lines. Anticancer activity measurements were carried out according to the Alamar Blue assay. Efficacy was established by comparison of the salts and silver compounds with <i>cisplatin</i>.