Hydrazone Metal Complexes Synthesis And Structural Chemistry

Acyl hydrazone complexes have received extensive attentions in recent years because of primarily to their biological and pharmaceutical activities. In this paper, we have designed and synthesized three new acyl hydrazone ligand, namely, diacetylmonoxime (4-methoxybenzoyl) hydrazone, 3-methoxysalicylaldehyde (4-methoxybenzoyl) hydrazone as well as benzoylacetone 4-methoxybenzoylhydrazone. Eight metal complexes were prepared by the reaction of various metal (Ni, Fe, Zn, V, Cu) salts and the above three ligands in organic solution with or without co-ligand, such as pyridine, quinoline. The crystal structures and properties of these complexes were characterized by elemental analysis, TG, IR spectra and X-ray single crystal diffraction. The results show that all the ligands have two isomers in solid state: ketone form versus enol form, in which the former one is more stable. There are H-bonding chain and layer structures in diacetylmonoxime (4-methoxybenzoyl) hydrazone and 3-methoxysalicylaldehyde (4-methoxybenzoyl) hydrazone,respectively. Acyl hydrazone ligands coordinate to metal centers to generate mononuclear or dinuclear complexes in tridentate fashion, and metal ions display distorted octahedral, square and trigonal bipyramidal geometries. TG analysis shows that the final residue are corresponding metal oxide.