Synthesis, Characterization Of Transition Metal Complexes Of Methyl-imino Asymmetric Schiff Bases And Its Catalytic Properties

Schiff base is a kind of very important ligand, and its functional group of -C=N-double bond is inclined to coordinate with metals and to be ring formation. Up to now, researchers in the world have synthesized and charactered kinds of Schiff bases, their metal complexes and exploited uses in many fields. Among them, the multidentate chelating ligands containing nitrogen and oxygen heteroatoms have the better ligand capability with transition metal atoms, and transition metal complexes of Schiff base have been studied in great details more and more, for their various coordinated feature. This kind of complexes, containing mononuclear, binuclear and polynuclear, are given more attention because their special useful for spectroscopic properties, catalysis properties, new material, medicine, simulating biology mechanis and so on. Therefore, design and synthesize some new Schiff base ligands and their complexes of transition metals have much signification in chemistry and biology.Thus, we synthesize salicylaldehyde and pyridinecarboxaldehyde Schiff base ligands and their transition metal complexes, which are used as oxidizing catalysts in H₂O₂-Vc system. Our main works are as following:1. Fourteen asymmetrical Schiff base ligands of salicylaldehyde containing different substituent groups and their copper(II), cobalt(II), nickel(II), zinc(II), manganese(II) and iron(III) complexes were synthesized, and characterized by elemental analysis, IR spectroscopy, also some of them were characterized by thermal analysis and single crystal X-ray diffraction.2. Four asymmetric pyridinecarboxaldehyde Schiff base ligands and their complexes with transition metal salts were synthesized and characterized by elemental analysis, IR and UV-vis spectroscopies, also some of them were characterized by thermal analysis and single crystal X-ray diffraction.3. We choose twenty-four complexes that derived from asymmetrical salicylaldehyde Schiff base ligands mentioned above as oxidizing catalysts in H₂O₂-Vc system. Investigation indicates that all of them reveal certain catalytic-oxidizing capability. We analysed and compared with the experimental result from metal ion, structure and substituent groups, founding that the catalytic capability of binuclear complex of Cu(II) is better than others.