Novel N-Heterocyclic Carbene Silver (I) Complexes: Synthesis, Structural Characterization, Antimicrobial, Antioxidant and Cytotoxicity Potential Studies

Nowadays, N-heterocyclic carbene-based silver-complexes Ag(I) have been widely used as an organometallic drug candidate in medicinal and pharmaceutical chemistry researches due to their low toxicity. Due to the success of Ag(I) complexes in biological applications, interest in the synthesis and applications of such compounds is increasing rapidly. Therefore, in this study, a series of unsymmetrical N,N-disubstituted benzimidazolium salts were synthesized as N-heterocyclic carbene (NHC) (2a-2j). The interaction of these benzimidazolium salts having their two nitrogen atoms substituted by bulky groups with Ag2O in DMF has been carried out to afford Ag(I) complexes and characterized by 1H NMR, 13C NMR, FT-IR and elemental analyses. The antimicrobial activity of Ag(I) complexes was tested against some standard culture collections of Gram-negative, Gram-positive bacterial strains and Fungal strains, which are the most frequently isolated among the society and hospital-acquired infectious microorganisms as potential metallopharmaceutical agents. The Ag-NHC complexes showed effective antimicrobial activity against microorganisms with MIC values between 0.0024 and 1.25 mg/ml. Moreover, these Ag-NHC complexes exhibited significant antioxidant activities. In addition, of benzimidazoles salts 2,4 and Ag(I) complexes 3,5 were screened for their antitumor activity. The highest antitumor activity was observed for 3e and 3d Complexes