Synthesis, structural characterization and pesticidal studies of lanthanide complexes with tridentate Schiff base ligands

Abstract

Tridentate Schiff base ligands 2-acetamido propanoic acid isonicotinoyl hydrazone (L1H2) and 2-acetamido acetic acid isonicotinoyl hydrazone (L2H2) and their Ln(III) metal complexes have been synthesized. Eight mononuclear lanthanide complexes of the type [Ln(L1)(L1H)].3H2O have been synthesized and characterized by elemental analysis (CHNO), magnetic susceptibility, electronic and spectral studies. Ligands and lanthanide complexes of the type LnCl3.6H2O (where Ln = La, Pr, Nd and Sm) react in 2:1 stoichiometric ratio. Electronic spectra indicate that there is slight covalent character in the bonding between metal and ligand. Magnetic moment values show that all metal complexes are paramagnetic except the La(III) complexes. The effect of Ln(III) complexes with selected ligand(L1H2) have been tested for pesticidal activity on Helicoverpa armigera and Spodoptera litura. As compared to the ligand, the complexes are found to have increased pesticidal activity.