SYNTHESIS, CHARACTERIZATION AND ANTIOXIDANT ACTIVITY OF SOME TRANSITION METAL COMPLEXES WITH TERPENOID DERIVATIVES

Abstract

A series of transition metal complexes of Fe(III), Co(II) and Cu(II) containing the bidentate N,O and N,S donor ligand, camphor semicarbazone (1,7,7-trimethylbicyclo [2,2,1]heptanesemicarbazone, TBHSC) and camphor thiosemicarbazone (1,7,7-trimethylbicyclo [2,2,1]heptanethiosemicarbazone, TBHTSC) have been synthesized and characterized by elemental analysis, molar conductance measurement and various spectral studies (IR, electronic and FAB Mass) and thermogravimetric analysis (TGA). All the metal complexes (1-8) are [M(LH)Cl 2 ] and [M(LH) 2 Cl 2 ] type, where M = Fe(III), Co(II) and Cu(II); LH = TBHSC and TBHTSC. TBHSC and TBHTSC act as neutral bidentate ligands in all the complexes. FAB mass spectroscopic studies of the three representative complexes (1), ( The proposed geometries of the complexes were octahedral geometry for 1:2 complexes, square planar for 1:1 complexes and distorted octahedral for Cu(II) complexes (1:2). The free radical scavenging activity of newly synthesized ligands (TBHSC, TBHTSC) and their metal complexes have been determined at the concentration range of 50-1000 g/ml by means of their interaction with the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). All the compounds have shown encouraging antioxidant activities. The least IC 50 value (111.0 g/ml) for compound (5) showed the potent scavenging property compared to other test compounds.