POLAROGRAPHIC BEHAVIOUR OF SOME DIVALENT METAL COMPLEXES OF 4-METHOXYBENZALDEHYDE THIOSEMICARBAZONE

Analysis of the complexes formed by 4-methoxybenzaldehyde thiosemicarbazone with Manganese (II), Iron (II),Cobalt (II) ,Nickel (II) and Zinc(II) metal ions was made through the polarographic technique. 4-methoxybenzaldehyde thiosemicarbazone was obtained by the reaction of hydrazinecarbothioamide with para-methoxybenzaldehyde in ethyl alcohol. Polarographic technique is best suited for the study of coordination complexes and their substitution reactions and more significantly the technique is especially useful in calculating stability constant of complexes that are formed by direct combination of metal ion and the ligands. A sharp change is observed in the E1/2 values of the transition metal ions in presence of the ligand indicating complexation .Irreversible polarographic behaviour has been shown in all the compounds studied and kinetic parameter αn and ko f ,h have been calculated .All the complexes prepared were found to have 1:2 stoichiometry.

Mechanochemical Synthesis and Potentiation of the Antimicrobial Activity of 4-[3-(4-methoxyphenyl)-allylideneamino]-1,5-dimethyl-2-phenylpyrazol-3-one by Metal Chelation

A Schiff base ligand, 4-[3-(4-methoxyphenyl)-allylideneamino]-1,5-dimethyl-2-phenylpyrazol-3-one has been synthesized by the condensation of Methoxycinnamaldehyde and 4-aminoantipyrine. Its divalent metal complexes of Co, Ni, and Cu were also synthesized using the mechanochemical solvent-free method. The ligand and the complexes were characterized by FTIR, UV/visible, 1H NMR, 13C NMR, and GC-MS. The ligand behaved as a bidentate donor by using its carbonyl and azomethine N as binding sites for the metals. The ligand showed low activity against some microbes but the complexes were remarkably active against the fungi species.

A Comprehensive Evaluation of Peripheral Analgesic and Antipyretic Activities of Divalent Metal Complexes of Indomethacin

Comparative peripheral analgesic and antipyretic activities of copper, zinc, cobalt and manganese complexes of indomethacin were studied. Peripheral analgesic effect of the complexes was evaluated by following acetic acid-induced writhing inhibition method in mice whereas antipyretic activity was assessed by Brewer’s yeastinduced pyrexia in rat model. At 10- and 20-mg/kg doses, the zinc-indomethacin complex produced significant writhing inhibition (p<0.001) by 67.35% and 77.55% whereas cobalt-indomethacin showed writhing inhibition by 61.22% and 64.63% in a dose dependent manner respectively, which were prominent compared to that of standard indomethacin (61.90% and 72.27% inhibition respectively). Moreover, the zinc-indomethacin complex exerted significant antipyretic activity at both 10- and 20-mg/kg dose by reducing body temperature from 100.38°F to 97.8°F (4th hour) and 100.36°F to 98.21°F (4th hour), respectively that were comparable to standard paracetamol. From this study, it can be said that, with further pharmacological and toxicological profiling of the zinc and cobalt complex of indomethacin, it may pave the way of discovering new drug entity.Dhaka Univ. J. Pharm. Sci. 16(2): 173-178, 2017 (December)