Research On The Dinuclear Complexes Of Schiff Base Macrocycle

In this dissertation, different dinuclear complexes of schiff base macrocycle have been studied. Nine novel dinuclear complexes were synthesized by cyclocondensation between 2, 6-diformyl-4-fluorophenol and diamine or triamine. These complexes were characterized by electrospray mass spectrum (ES-MS), infrared spectrum (IR), ultraviolet-visible spectrometry (UV-Vis), nuclear magnetic resonance (NMR) and X-ray diffractions techniques (X-ray). The electrochemistry characteristics between metal ions have been also depicted by recording the cyclic voltammograms of the complexes. In addition, the interactions with supercoiled DNA (pBR 322), the antibacterial activities of the complexes toward Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) and the cytotoxicity toward human hepatocellular carcinoma cells (Hep-G2) have been studied.These kinds of new compounds are expressed as follows (the structures of relative ligands are given in Figureâ… ):(1) Four homodinuclear complexes of tetra-nitrogen cycle ligands containing two phenoxide groups, such as [Cu₂L¹(CH₃OH)₂](ClO₄)₂ 1,[Zn₂L²(μ-OAc)]ClO₄ 2, [Mn₂L²(OAc)₂]·4H₂O 3, [Zn₂L³(μ-OAc)]ClO₄·0.5 CH₃OH 4.(2) Four homodinuclear complexes of hexa-nitrogen cycle ligands containing two phenoxide groups, such as [Ni₂L⁴(μ-OAc)(H₂O)(CH₃O)] (ClO₄)₂·3(H₂O) 5, [Mn₂L⁴(μ-OAc)(H₂O)]ClO₄·H₂O 6, [Mn₂L⁵(μ-OAc)] ClO₄·H₂O 7, [Ni₂L⁵(μ-OAc)]ClO₄·H₂O 8 .(3) One unsymmetric dinuclear zinc cryptate of hexa-nitrogen cycle ligands containing three phenoxide groups, [Zn₂L⁶]ClO₄·CH3OH 9 .The main work can be classified as following:1. Four dinuclear macrocyclic complexes 1-4 have been synthesized by stepwise template method with 2, 6-diformyl-4-fluorophenol and diamine as starting materials. The results show that: (1) Both the complexes 1 and 3 contain a symmetric centre. In the complex 1, two Cu²⁺ ions have the same coordination polyhedra which may be described as square pyramids, and the apical positions in the square pyramids are occupied by oxygen atoms of methanol molecules. In the complex 3, two Mn ions also have the same coordination polyhedra which may be described as distorted prisms. The Zn²⁺ ions in the complexes 2 and 4 have the similar coordination polyhedra which may be described as distorted square pyramids. In the complexes 1-4, the macrocycles are connected by H-bond. (2) The electrochemistry studies show that each of the complexes 1 and 3 behaves two pair of redox peaks in which both pair of peaks are pseudo-reversible in the range of potential 0 --1.4 V and 0.7 - -1.2 V, respectively. (3) All the complexes 1 - 4 can incise supercoiled DNA and the complexes 3 and 4 can incise supercoiled DNA to the nicked DNA (Formâ…¡) and the linear DNA (Formâ…¢) when the concentration is 400μM. (4) The antibacterial activities toward E. coli and S. aureus show that complex 2 exhibits remarkable antibacterial activity toward S. aureus, which is comparable to the antibacterial activities of benzylpenicillin sodium. The antibacterial activities of other complexes toward E. coli and S. aureus are not as well as that of the complex 2.2. Four dinuclear macrocyclic complexes 5-8 have been synthesized by stepwise template method with 2, 6-diformyl-4-fluorophenol, diethylenetriamine and N, N-bis (3-aminopropyl)-2-thiophenoethylamine as main materials. The results show that: (1) All the macrocycles of complexes 5-8 display saddle configuration. In the complex 5, both two side chains contain five-membered rings, and the coordination polyhedra of the two Ni²⁺ ions are different. In the complex 6, only one side chain contains five-membered ring, and the coordination polyhedra of the two Mn²⁺ ions are also different. The configurations of the complexes 7 and 8 are similar and the coordination polyhedra of metal ions in each complex are almost the same. (2) The electrochemistry studies show that the complex 5 behaves four reduction peaks and one oxidation peak in the range of potential 0 - -1.4 V. The complex 6 behaves two reduction peaks in the range of potential -1.2 - -2.4 V, but doesn't behave any oxidation peaks. The complex 8 behaves two reduction peaks and one oxidation peak in the range of potential -0.4 - -2.1 V, and that pair of redox peaks are pseudo-reversible. (3) All the complexes 5-8 can incise supercoiled DNA and the complex 6 can incise supercoiled DNA to the nicked DNA (Formâ…¡) and the linear DNA (Formâ…¢) when the concentration is 400μM. (4) The antibacterial activities show that the complex 5 exhibits high antibacterial activity toward E. coli and S. aureus, but not as high as that of complex 2 .The complexes 6-8 have antibacterial activities toward E. coli and S. aureus, which are not as well as that of the complex 2 and 6 .3. A novel dinuclear zinc cryptate 9 was synthesized by the [3+2] condensation between 2, 6-diformyl-4-fluorophenol and diethylenetriamine in the presence of zinc ions. (1) The crystal structure of the cryptate was characterized by X-ray diffraction techniques. This cryptate adopts an airscrew-form conformation with both amines and imines side chains. The coordination polyhedra around both zinc (â…¡) ions can be best described as the distorted prisms through three phenolate oxygen and three nitrogen atoms. (2) The reaction mechanism of this reaction is proposed based on the results of ES-MS and the crystal structure. According to the proposed reaction mechanism, adding Zn²⁺ is in order to afford a template which is useful for forming ring and adding triethyleneamine is to provide a strong nucleophilic middle reagent. The absolute methanol as solvent affords a reagent to dehydrate with intermediate. (3) The result of cytotoxicity toward human hepatocellular carcinoma cells (Hep-G2) reveals that this zinc cryptate exhibits high cytotoxicity toward human hepatocellular carcinoma cells (Hep-G2). (4) This cryptate has antibacterial activities toward E. coli and S. aureus.