Synthesis, spectroscopic studies and pesticidal activity of transition metal complexes with unsymmetrical schiff base

Unsymmetrical Schiff base glyoxal salicylaldehyde succinic acid dihydrazide (gssdh), and their Co(II), Ni(II), Cu(II), and Zn(II) complexes have been synthesized and analyzed. These complexes' structures are explained based on magnetic, electronic, IR, and NMR (1H and 13C) spectral studies. These ligands show monobasic tetra-dentate behavior, bonding through C=O, two C=N, and a phenolate group. Ni(II) complex show square planar geometry while Cu(II) and Co(II) complexes exhibit tetrahedral geometry in the solid-state shown by electronic spectra. However, Co(II) and Cu(II) complexes adopt octahedral geometry in DMSO solution. The insecticidal activity of these compounds is tested, and compared their activity with their standard. Synthesized compounds show moderate insecticidal activity at higher concentrations. At low concentrations, these compounds have anti-fungal and antibacterial properties but do not show the pesticide property.