The FT - IR and Malarial Biological Studies of Copper(II ) Complexes Containing Thiosemicarbazone and Semicarbazone Ligands Derived from Ferrocene and Pyridyl Fragments

Abstract

The Fourier Transform Infrared (FTIR) spectroscopic and malarial biological studies of complexes derived from the reactions of 2- acetylferrocenyl 4-phenylthiosemicarbazone, 2-acetylferrocenyl-4-methylthiosemicarbazone, 2-acetylpyridine2thiophenecarboxylsemicarbazone and 2-acetylferrocenyl-2-thiophenecarboxylsemicarbazone with copper(II) chloride are reported here. The ligands and complexes were synthesized using a method developed in our laboratory.The metal complexes and their corresponding ligands were tested against malaria parasites. It was found that in general the copper complexes synthesized are biologically more active than their corresponding ligands. In addition, detailed (FT-IR) studies of the ligands and complexes are re ported here for the first time. In recent years, metal complexes with sulfur ligands, such as thiosemicarbazide and its derivatives, have been the centre of attention because of their antitumor, antiviral, antibacterial,antifungal and antimalaria activities[1-2].Acetylferrocenyl thiosemicarbazone metal complexes are able to suppress the proliferation of normal or transformed tumour cells [3]. It was discovered that numerous ace tylferrocenyl thiosemicarbazone metal complexes inhibit the development of diverse experimental animals’ tumour (e.g. Ehrlichascites tumour, sarcoma 180, B16 melanoma and colon 38 carcinoma) and the growth of human carcinomas [4]. Certain ferrocenium compo unds were especially cytostatically found to be effective against human colarectal carcinomas [3-5). Omote [6] reported copper complexes with a thiosemicarbazone-containing ferrocenyl group. Garg and Kapur [7] also prepared cobalt complexes with monoacetyl ferrocene thiosemicarbazone. Recently,Kiremire and his group [8] reported that the metal complexes containing a dithio-based ligand were subjected to biological tests on falcipain -2 (FP-2)and falcipain-3 (FP-3)cystein protease enzymesfrom malaria parasiteP.falciparum .The complexes exhibited high biological activity. Other biological studies of acetylferrocenyl metal complexes that are in the literature include those by Bakir and his group [9] and Soumitra et al.(1998) [10] who reported the biological studies of thiosemicarbazone containing ferrocene and their metal complexes against gram positive and gram negative bacterial species. Although the synthesis and characterization of the ligands and their respective complexes using elemental analysis,1 HNMR ,13 CNMR and Massspectroscopic studies have already been reported, the biological studies against malarial parasites as well as the Fourier Transform-IR (FT-IR) studies of the complexes have not yet been reported. This paper describes the Fourier Transform Infrared (FT-IR) studies of metal-based thiosemicarbazone and semicarbazone-containing ferrocenyl group complexes and a brief report on the antimalarial activities of these complexes.