Synthesis, characterization, and antibacterial activities of a cobalt (II) complex of bipyridine derivative

The cobalt(II) complex of the formula [Co(5,5´-dmbipy)2 (NCS)2], was obtained by the reaction of Co(NO3)2·6H2O with 5,5´-dimethyl-2,2´-bipyridine and NaSCN. The metal complex was characterized through FT-IR, UV–Vis, 1H-NMR and elemental analysis. In vitro biological screening of the free ligand, complex and its metal salt against diverse microorganisms was done using Macro-dilution (tube) broth method. The antibacterial effects of complex have also been examined in vitro against standard bacterial strains. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and inhibition zones (IZ) of the complex, its ligand (5,5´-dmbipy) and its metal salt Co(NO3)2 ·6H2O against the growth of microorganisms (one Gram- positive standard strain of Staphylococcus aureus; S. aureus ATCC 25923, and one Gram-negative standard strain of Escherichia coli; E. coli ATCC 25922) are obtained. Comparison of the antimicrobial activities of the synthesized cobalt compounds with similar complexes in the literature shows that our new compounds are more strong [1,2].