The Syntheses, Characterization And Property Of Schiff Base Metal Complexes Constructed Through Derivatives Of Salicylal And 1, 3-Proplenediamine

Metal coordination complex is an important and attractive research field of chemistry. Recently, Sehiff base complexes have attracted increasing interests of chemists. Schiff base and its complexes are widely used in the fields of analytical chemistry, biology, metal corroded, and luminescent material. Thus syntheses of new Schiff base ligands are very important for the Schiff base complexes. Study on their properties and application are of special significance to the development of coordination chemistry. So far, studies on salicylaldehyde derivatives are mainly focused on the modification of their aromatic rings. However, new Schiff base ligands based on diamine and salicylaldehyde derivatives are rarely observed. The aim of this work is to design and synthesize new Schiff base ligands based on diamine and salicylaldehyde derivatives. Then six new Schiff base complexes: [ZnL¹]·H₂O·0.25EtOH (1), [Cu(II)L¹]·H₂O·0.25EtOH (2), [Cu(II)ClL²]·3H₂O (3), [Co(II)L¹]·7H₂O (4), [NiL¹]·2.5H₂O (5) and [NiL¹]·2.75H₂O (6), were obtained through assembly of the new Schiff base ligands and metal ions.In the first chapter, the concepts of Schiff, the histories and new developments of Schiff complexes are concisely introduced. At the end of this chapter, we pointed out the importance of the search project and summarized the important results obtained in the thesis.In the second chapter, we introduced the solvents used in this work. The preparation and data collection of crystals were also introduced.In the third chapter, a new Schiff ligand N,N'-(bis(2-phenoxyacete)formylidene) propane-1,3-diamine (H₂L¹) and its complex [ZnL¹]·H₂O·0.25EtOH (1) were synthesized. In complex (1), the coordination environment around the Zn(II) center is a distorted octahedron built from two phenoxo oxygen atoms, two carboxylate oxygen atoms and two imine nitrogen atoms.In the fourth chapter, the complex [Cu(II)L¹]·H₂O·0.25EtOH (2) was synthesized by the reactions of the H₂L¹ and Cu(II) dichloride in the solvents of water and ethanol, and [Cu(II)ClL²]·3H₂O (3) [L² = N-(o-oxy-acetate) benzyl-propylene- diamine] was prepared by HL1 and Cu(II) dichloride in the solvents of water and ethanol (pH =8⁹). The two compounds were characterized by elemental analysis,1H NMR, FTIR spectroscopy and single crystal X-ray diffraction analysis. There are one molecule (hostmolecule), one water molecule (guestmolecule) and quarter ethanol molecule in one asymmetric unit of complex 2, the Cu(II) atom exhibits a distorted octahedral geometry. There are one molecule (hostmolecule) and three water molecules in each unit of complex (3), the Cu(II) atom exhibits a distorted octahedral geometry. The complexes (2) and (3) exhibit good antibacterial properties, while the antibacterial properties decrease in the order: complex (3) > complex (2) > H₂L¹.In the fifth chapter, a new compound [Co(II)L¹]·7H₂O (4) was synthesized through the reaction of H₂L¹ with CoCl₂·2H₂O, where the central Co(II) center is six-coordinated by two phenoxo oxygen atoms, two carboxylate oxygen atoms, and two imine nitrogen atoms in a distorted octahedron. Finally, the H-bonding interactions between the water molecules and the carboxylate oxygen atoms stablize the structure of the title compound.In the sixth chapter, a new complex [NiL¹]·2.5H₂O (5) was synthesized through the reaction of H₂L¹ in CH3CH₂OH and Ni(II) dichloride. However, the new complex [NiL¹]·2.75H₂O (6) was synthesized by the reactions of the H₂L¹ and Ni(II) dichloride in water.The main conclusions are listed below through this work:1. The structure of Schiff base ligand, solvent, temperature and the types of metal ions have important effect on the complex structure. Among them mentioned above, the solvent, temperature and pH values are key factors during the formation of Schiff base complex.2. Because copper chloride (II) eassily hydrolysises in a certain alkaline solution with fracture of C = N bond, the solution should be strictly controlled in neutral during the syntheses of Schiff base copper (II) complex.3. The nature and scope of application of complexes mainly depend on ligand and the nature of metal ions. Metal ion electronic configuration also has an important impact on performance, such as: optical activity of zinc ions has important effects on optical activity of its Schiff base complexes.4. In this paper, antibacterial activity of some complexes has been discussed. Using diffusion method, the sample of bacteria-inhibiting bacterial growth inhibition zone sterile ring is used to describe the size of antibacterial circle antibacterial properties. The greater the inhibition zone, the anti-bacterial property is the better.5. The oxygen performance of the Schiff base cobalt complexes was tested. Schiff base complexes can be divided into two different forms: one is active type for oxygen (at room temperature they can quickly absorb oxygen); another is of non-activity type (they are stability at room temperature and do not absorb oxygen). Through oxygen experiment proved that Schiff base cobalt complexes is activity-based with a better role in oxygen absorption.