Synthesis, characterization and biological activity of rare earth complexes of 1-phenyl-3-methyl-5-hydroxy-4-pyrazolyl phenyl ketone isonicotinoyl hydrazone

The ligand, 1-phenyl-3-methyl-5-hydroxy-4-pyrazolyl phenyl ketone isonicoti noyl hydrazone (H2L), was prepared by condensation of 1-phenyl-3-methyl-4-b enzoyl-5-pyrazolone with isoniazid. Seven complexes of rare earths with H2L have been synthesized and characterized on the basis of elemental analyses , IR, UV, H-1 NMR spectra and thermal analyses. The general formula of the complexes is RE(HL)(3). 3.5H(2)O (where RE = La3+ - Gd3+). It has been disc overed that the ligand and its completes of the light rare earth metals pos sess antioxidative activity and inhibitory action on lipid peroxidation.