SYNTHESIS AND ANTIMICROBIAL ACTIVITY STUDIES OF TRIIODOIMIDAZOLE AND ITS TRANSITION METAL COMPLEXES

Abstract

2,4,5-Triiodoimidazole (TII) was synthesized  by reacting an aqueous solution of iodine and potassium iodide with imidazole. The Co (II), Cu (II), Cr (III) and Fe (II) complexes of the ligand were also synthesized. All the compounds prepared were purified by recrystalisation with suitable solvents and their purities checked by their melting point and thin layer chromatographic pattern. Structural elucidation of the synthesized compounds was done by Nuclear Magnetic Resonance (NMR), Infrared (IR) and Mass Spectroscopy (MS) analysis. Some absorption bands in the IR spectrum of the iodinated imidazoles were found to shift either to higher or lower wave numbers in the complexes, indicating the involvement of azomethine nitrogen in coordination to the metal ion. Appearances of medium bands at 540-620 cm-1 in some complexes were supportive in assignment of the proposed coordination sites. The synthesized TII and its metal complexes were screened for their antimicrobial activity against Proteus spp, Pseudomonas aeruginosa, Streptococcus pyogenes, Staphylococcus aureus, Aspergillus spp, Candida spp and Trichophyton spp. TII showed minimal activity against the selected bacterial strains when compared to Levofloxacin, a broad spectrum antibiotic. The synthesized complexes of the ligand did not give a substantial improvement on their bactericidal activity. Although the fungi strains showed little or no sensitivity to TII when compared with a standard antifungal agent such as Ketoconazole, its Co2+ complex was found to show geometric increase in antifungal activity, which surpassed the standard drug agent. This presents the Co2+ complex of TII as a lead in the search for medicinally active compounds against these organisms. Keywords: Imidazole, triiodoimidazole, metal complexes, spectroscopy, antifungal