Nematicidal Activity Studies of Cu^2+and Zn^2+Complexes with Some Aldimine Ligands Against MeloidogyneArenaria: A Root Knot Nematode of Arachis Hypogea

Two Schiff base donor ligands (aldimines) were used to prepare four transition metal complexes of Cu(II) and Zn(II) by treating 2-nitroaniline and salicylaldehyde to form the Schiff base ligand 2[(2-nitrophenylimino) methyl] phenol (L1) and 4-nitroaniline and salicylaldehyde to form 2-[(4-nitrophenylimino)]methyl]phenol (the L2 counterpart). The processes were accomplished using a microwave oven assisted reaction regulated at 100˚C for 30 min. Characterization was carried out on the basis of physical properties elemental analysis, FTIR, ^1H-NMR and ^13C-NMR spectroscopy, electronic spectral and mole ratio method. Results from the FTIR spectra of the ligands and corresponding complexes showed that the ligands L1 and L2 displayed a bidentate character with coordination via the nitrogen and oxygen atoms. The 1H-NMR and 13C-NMR data of L1 and L2 confirmed the formation of the complexes of Cu(II) and Zn(II) showing that the probable coordination geometries of Cu(II) and Zn(II) are octahedral. The complexes were found to be non electrolytes in alcohol. The nematicidal activity studies implied that the ligands and their metal complexes showed promising nematicidal ability with the metal complexes showing comparatively higher inhibiting ability than the free ligands against the root knot nematode Meloidogyne arenaria present in the crop Arachis Hypogea.