Abstract
Series of oxaloyldihydrazone ligands were prepared essentially by the usual condensation reaction of oxaloyldihydrazide with different aldehydes e.g., salicylaldehyde, 2-hydroxy-1-naphthaldehyde, 2-hydroxyacetophenone and 2-methoxy-benzaldehyde in 1: 2 molar ratio. The formed compounds were purified to give bis(salicylaldehyde), bis(2-hydroxy-1-naphthaldehyde), bis(2-hydroxyacetophenone) and bis(2-methoxy-benzaldehyde) oxaloyldihydrazone (L-1, L-2, L-3 and L-4), respectively. The structures of the hydrazones (L-1-L-4) and their relevant solid cobalt(II) complexes have been ascertained on the basis of data obtained from elemental analyses, spectral UV-Vis., IR, ESR, mass and H-1/C-13 NMR measurements, magnetism at different temperatures and thermal (TG) analysis. The dihydrazones coordinate to the metal center forming mononuclear complexes with L1 and L4 in addition to binuclear complexes with L-2 and L-3. The cobalt ion preferred octahedral configuration upon chelation. Variation of magnetic susceptibility with temperature referred to the conversion of Co(II) complexes under the effect of heat/oxygen to analogous Co(III) complexes. The band gap energy values of all compounds are characteristic of semiconductor materials. The investigated complexes were assayed for their antitumor activities against the human breast cancer cells (MCF-7). The results suggested that the synthesized Co(II) complexes possess growth inhibition activities. Furthers, the toxicity of Co(II)-L-3, L-4 towards the African Green Monkey Kidney cells (VERO cells) were checked.