Antimicrobial and antioxidant studies of novel mixed-metal complexes of benzoyl-aminoethanoic acid-nicotinamide: Microwave-assisted green synthesis, spectroscopic characterization and molecular modeling

Abstract

Purpose: To enhance the antimicrobial and antioxidant activities of benzoylaminoethanoic acid (BAEA) and nicotinamide (NA). Methods: Complexes of benzoylaminoethanoic acid (BAEA) and nicotinamide (NA) were prepared in a microwave oven. These metal complexes were evaluated by various techniques including 1H and 13C nuclear magnetic resonance spectrometry (NMR), infrared spectrometry (IR), ultraviolet-visible spectrometry (UV), mass spectrometry (MS), thermogravemetric analysis (TGA) and molar conductivity. The synthesized compounds were screened for both antibacterial and antifungal activities using disc diffusion technique. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method was used to assess the antioxidant activity of the complexes. Results: Based on the results of spectroscopic techniques and physicochemical characterization, these complexes have been named [Cu(NA)2(BAEA)Cl2], [Co(NA)2(BAEA)Cl2], and [Ni(NA)2](BAEA)Cl2], respectively. A model structure with a distorted octahedron was proposed based on the outcome of the magnetic, analytical and spectral analyses. Synthesized metal complexes were more effective and efficient than nicotinamide and benzoylaminoethanoic acid. Conclusion: Efficiently synthesized mixed metal complexes were prepared using a simple, eco-friendly rapid green chemistry methodology. The newly synthesized complexes have significant antimicrobial activities against the test bacterial and fungal strains.