| Researching on the interactions between oligopeptide conjugates and metal ions makes significant contribution in the fileds of biochemistry, biaochmemical sensor and environmental secience. Histidine, a necessary amino acid containing a functional sidechain, widely exists in functional proteins and chelats with metals ions, which plays an important role in the structural and functional maintaining of the proterins. The thesis mainly contribute to develop novel materials of ferrocene-oligopeptide conjugates containing histidine, and investigate their interations with metal ions in solution phase or in the self assembled film, and construct a biomimetic model of carbonic anhydrase for CO2 sequestration.Granphene oxide is the anologue of graphene, which has great potential to be modified by chemists due to its solution dispersible and chemical functionalized abilities. The thesis also demonstrated a covalent graphene oxide-dye nanohybrid, and investigated its optoelelctric conversion triggered by F- ions.The main contents and results are generalized as follows:In Chapter 1, the research background of ferrocene-oligopeptide conjugates, biomimetic of carbonic anhydrase and the nanohybrid involving graphene oxide was reviewed.In Chapter 2, a novel ferrocene-oligopeptide conjugate Fc-[His(DNP)-Gly-OMe]2 was synthesized and characterized. The conjugate displays a 1, 2'-P helical conformation in solution and exhibits a reversible one-electron redox property with a half wave potential of 380.5 mV vs. Fc/Fc+. The interactions of metal ions Na+, Mg2+, Fe2+, Cu2+, Zn2+, and Cd2+ with this conjugate were studied via cyclic voltammetry, NMR and CD spectroscopy. Electrochemical studies exhibited rare cathodic potential shifts upon additions of metal ions, which followed the order Cu2+(-436 mV)> Fe2+(-284 mV)> Zn2+(-270 mV)> Cd2+(-238 mV)> Mg2+(-180 mV)> Na+(-75 mV). For Fe2+, Cu2+, Zn2+and Cd2+ions, a 1:1 metal complex was postulated on the basis of the results from cyclic voltammetry and NMR spectroscopic titration experiments and electrospray mass spectrometry. NMR studies showed that the metal ions chelated with the conjugate through the imidazole nitrogen atoms in the side chain of histidine. As was confirmed by circular dichroism spectroscopy, the metal ions coordination changed the conformation of the ferrocene core which was dependent on the particular metal ion and its coordination preferences. P-helicity of the conjugate is maintained for Zn2+ and Cd2+ ions, and M-helicity is adopted for Fe2+ and Cu2+ ions.In Chapter 3, a ferrocene-histidine conjugate containing a disulfide bond was successfully synthesized and its self assembled film was formed on gold surface through Au-S bond. They were fully characterized and their interactions with Zn2+/Cd2+ ions were investigated, respectively. The conjugate exhibited a reversible one-electron redox property in solution, and its half wave potential is 838 mV vs. Ag/AgCl, which showed anodic potential shift with an amplitude less than 20 mV upon addition of Zn2+or Cd2+ions. Its self assembled film exhibited a reversible one-electron redox property on gold electrode surface, and its half wave potential is 701 mV vs. Ag/AgCl. Good surface cover status of its immobilized film on gold surface is supported by the blocking experiments at the presence of K3Fe(CN)6. Its immobilized film showed dramatic current decrease in the corresponding cyclic voltammograms after interaction with metal ions. Zn+ions resulted in a much stronger decrease than Cd2+ions, which was supported by the results from electrochemical impedance spectroscopy. X-ray photoelectron spectroscopy results implied that the binding sites of Zn+ ions with the films were different form those of Cd2+ions.In Chapter 4, an immobilized artificial carbonic anhydrase model for CO2 sequestration was established by immobilizing a novel ferrocene-histidine conjugate on gold surfaces and then chelating with Zn2+ions. X-ray photoelectron spectroscopy analysis suggested that the active centers were formed by the binding of Zn2+ions with imidazole nitrogen atoms, and the ratio between them was around 2.5:1, near to 3:1, the ratio between Zn2+ions and nitrogen atoms in the active center of natural carbonic anhydrase. Its catalytic activity on CO2 (gas/aqueous solution) substrate was conformed by electrochemical methods. The optimized catalytic conditions and the catalytic parameters were investigated using p-nitrophenyl acetate in acetonitrile as substrate. The optimized pH was obtained as 7.51. The values of K'm and kcat were obtained as 27.2 mM and 506.5 s-1 accroding to Michaelis-Menten equation.In Chapter 5, a covalent nanohybrid based on graphene oxide and a fluorescein derived tert-butyldiphenylsilyl ether was prepared by organic synthetical method. Its structural property was investigated by UV-vis and FIT-IR spectrometry. Its morphology was observed by atomic force microscopy and transmission electron microscopy. The triggering ability of F- ions on the cleavage of Si-O bond in the nanohybrid and the fluorescein derived tert-butyldiphenylsilyl ether was confirmed by UV-vis and emission spectrometry, respectively. The contrast experiments upon addition of Cl", Br- and I- ions suggested that F- ions could selectively trigger the cleavage of Si-O bond in the nanohybrid and consequently, resulting in a specific photocurrent response under the irradiation of white light. Similar phenomena were observed in the contrast experiments irradiated by homogeneous light 509 nm. No obvious photocurrent response was exhibted by the fluorescein derived tert-butyldiphenylsilyl ether under the same experimental conditons.In Chapter 6, the conclusion was shown.
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