Synthesis, spectroscopic determination and in vitro antimicrobial studies of cobalt(ii) and nickel(ii) complexes of a Schiff base derived from 1h-indole-2,3- dione with hydrazinecarbothioamide

Condensation of H-Indole-2,3-dione with Hydrazinecarbothioamide produced a Schiff base (2Z)-2-(2-Hydroxy-3H-indol-3- ylidinehydrzinE- 1-Carbothioamide. Cobalt(II) and Nickel(II) complexes, were prepared by the interaction of the metal(II) salts with the synthesized Schiff base. The prepared compounds were analysed by magnetic susceptibility, molar conductance, FTIR, AAS, solubility absorbance and empirical formula. The complexes showed moderate values of decomposition temperatures. Infrared spectral data of the Schiff base and the complexes, indicated coordination of the Schiff base to the metal(II) ions via azomethine nitrogen, indole oxygen and thione sulphur. The effective magnetic moment of the complexes suggested an octahedral geometry. The molar conductivities indicated a non- electrolytic nature of these complexes. The results of the absorbance and the empirical formula showed that, the Schiff base is monobasic and tridentate in nature towards the metal ions. Both the ligand and the complexes were screened for antimicrobial activity against Staphylococcus aureus, Salmonella typhimurium, Escherichia coli (bacteria); Aspergillus flavus, Aspergillus fumigatus and Mucor (indicus species) (fungi). Amoxicillin and Ketoconazole were used as positive control for the bacteria and fungi isolates respectively. The results showed that the complexes are more active than the free ligand but less active when compared with the standards.