Synthesis, Characterization And Properties Of The Open-loop Multi-nitrogen Complexes

This dissertation uses the multi-nitrogen complexes with pendant-arm as research objects, focusing on the synthesis, characterization and properties of them, aiming to synthesize unique polynuclear complexess. Six novel open-loop complexes, [Ni(L¹)₂]·2(CH₃OH) 1,[Ni(L²)₂]·2(CH₃OH) 2,[Cu(L³)₂] 3, [Cu₄(L⁴)]2+ 4,[(L⁵)Ni₂Mn₂] 5, [Cu(L⁶)Cl₂]₂ 6, have been synthesized and characterized by infrared spectra, electrospray mass spectrum, element analyses and X-ray diffractions techniques. The electro-chemistry properties of the complexes have been studied by the measurements of cyclic voltammograms. In addition, the binding of CT-DNA and the cleavage activities of plasmid DNA pBR322 of the complex 1,2,3,5 and complex 6 have been also investigated.The work is composed of :1. Open-loop schiff base complexes with pendant-arm have been prepared from the condensation reation of 2-aminoethanol with 5-chlorosalicylaldehyde or 5-fluorosalicylaldehyde. Both of the complex 1 and complex 2 are mononuclear nickel complexes whose metal coordination environment can be described as a distorted octahedron. One-dimensional structures of the two complexes are maintained by the hydrogen bond interactions. The structure and composition of complex 1 and complex 2 are very similar except substituents in benzene rings, F for 1 and Cl for 2. The results of the cleavage reactions of pBR322 DNA and the binding of CT-DNA with them, reveal that the complex with F substituent have the better cleavage ability than that of the complex with Cl in spite of the same reaction mechanism. Cyclic voltammetry indicates that the complex 2 has a pair of reversible redox peaks. 2. The complex 3 was obtained by the reaction of the reduced product of a Schiff base ligand which is obtained form 2-aminoethanol and 5-fluorosalicylaldehyde and copper(Ⅱ) ionsThere is a little difference between 1 and 3 in the aspect of spatial structure. After we research its ability of cleavage, It shows that 3 have the ideal effect.3. The multinuclear complexes 4,5,6 are synthesized from 5-fluorosa licylaldehyde,2-aminoethanol or isopropanolamine. Complex 4 is a Cu-O cluster tetranuclear Cu(Ⅱ) complex with a distorted cubic Cu₄O₄ core. The one dimensional chain structure is formed through the hydrogen bond interactions.Complex 5 is a tetranuclear Ni₂Mn₂ complex whose crystal structure is very novel. Every metal ion has the different coordination environment. In the molecule 5, the Ni(Ⅱ) and Mn(Ⅱ) ions are bridged by an acetic acid molecule. There are aboundant hydrogen bond interactions in both intramolecule and intermolecules. According to cleavage results, complexe 5 has a good cleavage activity and the cleavage effect increased with the concentration of the complex. By the way the combining way is inserting.In addition, the research about magnetism of complexes is underway.4. complex 6 is a bis(μ-chloro)-bridged copper(Ⅱ) Schiff basecomples. The coordination of copper(Ⅱ) ion can be seen as a distorted tetragonal pyramid. in the DNA cleavage activity of the complex increases with the enhance of the concentration of the complex.