Copper Methacrylate Complexes with Benzimidazole Derivatives: Structural Characterization and Antimicrobial Assays

Abstract

In order to design antimicrobial species, a series of methacrylate (Macr) complexes, [Cu(HBzIm)2(Macr)2] (1), [Cu2(HBzIm)2(Macr)4] (2), [Cu(2-MeBzIm)2(Macr)2] (3), [Cu2(2-MeBzIm)2(Macr)4] (4), and [Cu(5,6-Me2BzIm)2(Macr)2] (5) (HBzIm = benzimidazole, 2-MeBzIm = 2-methylbenzimidazole, and 5,6-Me2BzIm = 5,6-dimethylbenzimidazole) were synthesized and characterized by several spectral techniques, as well as by single crystal X-ray diffraction. The mononuclear species exhibit a distorted octahedral stereochemistry, while the binuclear types, with a paddle-wheel structure, adopt a square pyramidal surrounding. The methacrylate acts either as a chelate or a bridge, while all benzimidazole derivatives are coordinated as unidentate. The supramolecular networks are developed by both intermolecular π–π stacking interactions and hydrogen bonds. The antimicrobial assays provided both complexes the ability to inhibit planktonic strain proliferation, as well as to adhere on inert substratum. All complexes exhibit a moderate antimicrobial activity, both in regards to standard and clinical isolate strains, the most active being compound 5 against Candida albicans, with a minimum inhibitory concentration (MIC) of 0.156 mg/mL. It is worth mentioning that complex 1 inhibited the microbial adhesion of the clinical Escherichia coli strain and complex 2 constrained that of the clinical C. albicans strain.

Keywords

• Cu(II) complex
• benzimidazole
• methacrylate
• crystal structure
• microbial adhesion