| Summary: | 碩士 === 國立清華大學 === 生醫工程與環境科學系 === 94 === Activation of hydrogen peroxide by Cu(II) complexes of 20 native amino acids (L) and β-Ala has been studied by measuring the initial oxidation rate of quinaldine blue(QB) in aqueous phosphate media at 25°C. System parameters such as pH, ionic strength, temperature and concentrations of Cu(II), amino acids, and hydrogen peroxide are examined to characterize the effects of Cu(II) speciation. The oxidation rate of QB is first order in Cu(II)-amino acid complexes and variable order in hydrogen peroxide, which can be explained in terms of Michaelis-Menten kinetics. Among 20 native amino acids and β-Ala, Cu(II)-histidine complex could more easily activate hydrogen peroxide than any other Cu(II)-amino acid complexes. The catalytic activities vary by about 500-fold and are discussed in terms of the ligand structure and function group, which affects the formation of lignad-Cu(II)-peroxide complexes. The catalytic activities of Cu(II) complexes with all 20 amino acids demonstrate that the 1:1 Cu(II) complexes (CuL) are the dominant species forming the active copper complex catalyst. Based on the experimental results of Cu(I) and Cu(II) complex systems and product measurement, a peroxide activation mechanism is proposed .
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