Asian Journal of Physical and Chemical Sciences

Four new transition metal complexes were synthesised for in-vitro antibacterial and antifungalscreening. Already prepared Schiff base and an N-based donor chelators (2,2-bipyridine) were successfully used for the production of the metal complexes in a stoichiometric ratio 1: 1: 1. The study aims to explore the antibacterial and antifungal assay of Fe, Ni, Cu and Zn(II) complexes derived from schiff base base ligands. The metal(II) salts were differently measured FeSO₄.7H₂O (0.199 g), Ni(CO₂CH₃)₂.4H₂O (0.179 g), Cu(CO₂CH₃)₂.2H₂O (0.156 g) and Zn(CO₂CH₃).2H₂O (0.158 g) and differently added to the mixture of the chelators, 0.5 g (7.18 x 10^-4 mol) of N-(2-hydroxy-1-naphthaldehyde)-2-amino-6-nitrobenzothiazole (C₁₈H₁₁N₃O₃S) and 0.223 g of 2,2'-bipyridine (C₁₀H₈N₂) the next step was the addition of 10 mL of CH₃CH₂OH and 8 drops of triethylamine (CH₃)₃NH₃. This was then subjected to reflux for 6 h between 40 – 60 ^oC, placed on a magnetic stirrer. On the expiration of the reaction time, products were obtained which were then cooled at room temperature (RT), filtered and dried. The mass and % yield were also calculated. The structural elucidation of the novel complexes machinewas carried out with the aid of FT-IR, UV-visible spectroscopies, and a melting point machine, machine while the solubility test was conducted using six different solvents. Using the agar diffusion method, the in-vitro antibacterial and antifungal assay was carried out with three different fungi (Aspergillus niger, Rhizopus stalonfer and Aspergillus flaus) and six different bacteria (Klebsiella pneumoniae, Proteus mirabilis, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus and Salmonella typhi) and The complexes had inhibitory activity against the six bacteria in the range 2.0 – 12.0 mm. [Cu(C₃₆H₂₂O₁₁N₆S₃Cl₂]nH₂O and [Zn(C₃₀H₂₁O₃N₅S)]nH₂O complexes were able to inhibit all the bacterial strains in the range (2.0 – 11.0 mm) and so, are the best performed and [Fe(C₂₈H₁₈O₅N₅S₂]nH₂O the least performed. On the other hand, the complexes inhibited the fungi in the range 1.0 – 17.0 mm with [Fe(C₂₈H₁₈O₅N₅S₂]nH₂O reported as the best performed in the range 11.0 – 17.0 mm, while [Zn(C₃₀H₂₁O₃N₅S)]nH₂O was the least performed. The standard drugs used for this study outperformed the complexes in bacterialthe range 9.0 – 19.0 mm for streptomycin against bacteria  bacterial and 16.0 – 19.5 mm for miconazole against fungi, except in one case where the newly synthesised Fe2+ complex performed better than the standard against Rhizopus stalonfer.