Mixed metal complexes of isoniazid and ascorbic acid: chelation, characterization and antimicrobial activities

Novel mixed complexes of isoniazid and ascorbic acid have been synthesized and characterized using infrared, electronic absorption data, elemental analysis, molar conductivity, melting point, thin layer chromatography and solubility. The metal ions involved in the complex formation are Cu2+, Zn2+ and Cd2+. The melting points of the synthesized compounds were in the range of 170- 316oC while the conductivities measured in the range of 7.67- 9.04 μs. The infrared spectra data of these ligands and their metal complexes have revealed the bi-dentate coordination of isoniazid ligand to the metal through the oxygen of the carbonyl and nitrogen of the amine group and ascorbic acid coordinating through the carbonyl and C-2 enolic hydroxy groups. The antimicrobial studies of the synthesized compounds on micro-organisms such as: Escherichia coli, Staphylococcus aureus, Pseudomonas aureginosa and Salmonella typhi at a concentration of 1 mg/ml revealed that all the ligands and complexes have good antimicrobial activities. The complexes showed enhanced activities against the microorganisms. This research work is focused on the synthesis and characterization of Cu2+, Zn2+ and Cd2+ complexes of the ligand isoniazid and Ascorbic acid and their antimicrobial activities.