Nematicidal Activity of Cu(II) and Fe(II) Schiff Base Ligand Complexes: Synthesis and Characterisation

The Schiff base (E) – N1- (2 -hydroxybenzylidene)nicotinohydrazide and its metal complexes of Cu(II) and Fe(II) have been successfully synthesized and characterized physiochemically and spectroscopically. The ligand and the complexes were obtained in good yield ranging from 74% - 76%. The compounds were solid; air and moisture stable with melting point 231 - 245°C. The FT IR spectroscopic data shows appearance of the azomethine (C=N), carbonyl group (C=O) and C-O of phenolic group peak at 1614cm-1, 1644 and 1357 cm-1 respectively in the spectrum of Schiff base and lower by 52 – 29 cm-1, 45 cm-1 – 30 cm-1 and 67 cm-1 – 59cm-1 in the spectra of the complexes respectively, signifying tridenticity of the Schiff base upon interaction with the metal ions. The molar conductivity data of the Schiff base was found to be 4.0 ᅿ-1cm2mol-1 indicates non electrolytic nature of the ligand whereas that of the complexes ranges between 142 -162 ᅿ-1cm2mol-1 indicating that the complexes were weak electrolyte in DMSO. On the basis of magnetic and electronic spectral data, octahedral geometry was proposed for all the complexes. The powdered x ray diffraction data suggests orthorhombic crystal system for the complexes and the thermal behaviour (TGA/DTA) of the synthesized complexes shows Cu(II) complexes having four stages of decomposition while Fe(II) complexes showing three stages of decomposition with the first stage showing lost of one lattice of water molecule. The nematicidal activity was studied in terms of egg hatch and mortality; and the compounds exhibited nematicidal properties, with hatching rate ranging from 3.0 to 48% and mortality rate ranging from 6.5 to 95 (%). The results revealed that the hatching rate increases with decrease in concentration while the mortality rate increases with increase in concentrations and time. This is evident that the nematicidal activity is time and dose dependant.