Antibacterial and Antifungal Assay of Fe, Ni, Cu and Zn (II) Complexes Derived from Schiff Base Ligands

Abstract

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.