| The catalytic activity of metalloenzyme would be related to the active center and the nearby micro-environment which has the important biological function. Artificial nucleases have the vital scientific significance for the design of the restriction endonuclease and gene drug.The mimic of superoxide dismutase is an effective way to the development of the exogenous chemicals medicine for oxidative stress and superoxide free radical.In this paper, the metal complexes with the ligands of amantadine derivatives were assembled with β-cyclodextrin for the construction of the water-soluble enzyme models. Also, the hybrid systems with the silica nanoparticles and the salen copper complexes were synthesized and performed the full characterization. Moreover, the activity assay of superoxide dismutase and catalase had been carried out. This paper contains the following four parts:1. Two complexes 1 and 2(1=ZnL1(Cl)2; 2=CuL1(Cl)2, L1=N,N’-bis(2-pyridylmethyl) amantadine) and the β-cyclodextrin inclusion complexes 3 and 4(3=ZnL1(Cl)2@β-CD;4=CuL1(Cl)2@β-CD) were synthesized and characterized by 1H NMR, UV-vis, elemental analysis,infrared spectrum and X-ray single crystal diffraction. In the crystal structures of 3 and 4, metal ions were coordinated with the three nitrogen atoms of L1 and two chlorine ions with the distorted square pyramidalconfiguration, and the adamantyl group was insert into the cyclodextrin cavity from the second surface by the hydrophobic interaction. By means of ESI-MS spectra, it would be found that the two weak ligand of chloride ions could be exchanged with the solvent molecules of water /acetonitrile in the solution. From the experiment of pH potentiometric titration for 3 and 4 in aqueous solution, the pKa value of [ZnL1(OH2) 2]2+(pKa1=8.02; pKa2=9.65) can be deduced, indicating that the steric hindrance of cyclodextrin can effectively prevent the formation of the hydroxyl bridged dimers. The hydrolysis dynamics have been performed with the substrate of bis(p-nitrophenol) phosphoric acid diester(BNPP).The second-rate constants for the single and double hydroxyl active species were 4.20×10-4 and 2.53×10-3 M-1 s-1 respectively. The catalytic second-rate constant of zinc complex is more than three times, compared with the reported zinc complex with the ligand of 1,10-phenanthroline bridged bis-cyclodextrins.2. Two complexes 5 and 6(5=ZnL2(Cl)2; 6=CoL2(Cl)2,L2=N,N’-bis(2-quinolinelmethyl) were synthesized and characterized by1 H NMR, UV-vis, elemental analysis, infrared spectrum and X- ray single crystal diffraction. From the analysis of the crystal structures, metal ions were coordinated with the three nitrogen atoms of L2 and two chlorine ions forming the distorted square pyramidal configuration. From result of the catalytic hydrolysis dynamics with the substrate of p-nitrophenolacetate(p-NA), the catalytic activity of 5 and 6 were higher than 1 under the same conditions.3. Salen copper complexes with the quaternary ammonium salt side arm were synthesized, further supported on silica nanoparticles to build complex-nano hybrid system, wich had been characterized by SEM, TEM,ICP, infrared spectrum and energy spectrum method. The catalytic activity of superoxide anion radical disproportionation were assayed.Under the same conditions, the activity of hybrid system SiO2@CuSalImQA was higher about 22% than SiO2@CuSal, due to the electrostatic attraction between the O2-? negative charge and the positive charge provide by the quaternary ammonium side arm.4. Three copper complexes were synthesized with the ligands of1-methyl-2-hydroxymethyl imidazole and pyridine-2-amino-1-adamantanecarboxamide, and the products were characterized by elemental analysis, UV-vis, IR and X- ray single crystal diffraction.Electrochemical properties of them were measured by cyclic voltammetry,and SOD activities were measured by the method of methionine-NBT illumination. |
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