SYNTHESIS, CHARACTERIZATION, AND BIOLOGICAL APPLICATIONS OF 4-ISOPROPYL BENZALDEHYDE SEMI AND THIOSEMI CARBAZONES AND THEIR Mn(II) AND Fe(III) METAL COMPLEXES

Four complexes, [Mn(L1)2Cl2] (1), [Fe(L1)2Cl2)] (2), [Mn(L2)2Cl2] (3), [Fe(L2)2Cl2)] (4), were prepared by reacting 4-isopropyl benzaldehyde semicarbazone and thiosemicarbazone ligands with MnCl2.4H2O and FeCl3.6H2O. The infrared, UV, 1H NMR, 13CNMR, EPR and mass spectra of the complexes have been assigned. Thermogravimetric analyses (TGA, DTA) were also carried out. The data agree quite well with the proposed structures and show that the complexes were finally decomposed to the corresponding ligands. The ligands and their metal complexes were screened for antimicrobial activities by the disc diffusion technique using DMSO as solvent. The minimum inhibitory concentration (MIC) values for 1–4 were calculated at 30°C for 24–48 h. The activity data show that the thiosemicarbazone metal complexes are more potent antibacterials than the semicarbazone metal complexes. The complexes were also screened for their anti oxidant properties, which are comparatively lesser for manganese complexes than for iron complexes.