Title page for etd-0113118-093744


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URN etd-0113118-093744
Author Yi-Chien Liu
Author's Email Address No Public.
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Department Chemistry
Year 2017
Semester 1
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Synthesis and design of copper complexes for the degradation of dimeric lignin substrates containing β-O-4 linkage and biomimetic studies of copper complexes for self-exchange electron transfer
Date of Defense 2018-01-24
Page Count 112
Keyword
  • self-exchange electron transfer
  • enzyme
  • blue copper protein
  • reorganization energy
  • selective activation
  • copper complex
  • Lignin
  • renewable resources
  • Abstract The exploitation of oil’s has exponentially increased from the industrial revolution in 20’s century. Find a renewable resources as alternatives for oil is unavoidable. The tree leaves, wheat straw, and wood chips have not been taken a good uses. The cell wall of plants are consisted of cellulose, semicellulose and lignin. In particular, lignin is the only known biomass resource made up aromatic rings, which is potential to become the raw material of valuable chemical feedstocks.
    In the research, we have synthesized and designed a copper complex 1 to react with dimeric lignin model substrates under the O2. Complex 1 is coordinated by O, N, O atoms and another O to form a distorted Td structure. Based on experimental results, complex 1 can selectively react with dimeric lignin substrates under O2. From a combination of IR、UV and NMR spectra, we suggests that the dimeric lignin substrates was degradation to benzoic acid and benzoate, and others compounds. The conversion of these transformation is moderate to low (20-30%) due to production of benzoic acid that is a stronger ligand than tridentate [O,N,O] ligands that is coordinated to the Cu center.
    Based on the EPR spectrum and effective magnetic moment determined by the Evan’s method of complex 2, the electronic structure of complex 2 is best described as weakly antiferromagnetic coupling between CuII centers.
    Electron transfer is a vital process for modulating the functions of diverse enzymes. Nature has adopted a transition metal containing cofactors that exhibits optimized coordination environments and oxidation state to exert rapid electron transfer.
    In this research, we have synthesized and designed multi-dentate ligands to coordinate on mono-nuclear copper center in order to understand the factors determining self-exchange electron transfer rate as well as the activation energy for reorganization energy.
    From the measurements of cyclic voltammetry and variable temperature NMR wide broaden experiments, we have determined the redox potential and rate constant of self-exchange electron transfer, respectively. According to Marcus theory, we can calculate the value of reorganization energy as 0.67 eV which is close to the one observed in blue copper protein (0.6 eV).
    Advisory Committee
  • Jyh-Tsung Lee - chair
  • Michael Yen-Nan Chiang - co-chair
  • Sodio Hsu - co-chair
  • Ming-Li Tsai - advisor
  • Files
  • etd-0113118-093744.pdf
  • Indicate in-campus at 5 year and off-campus access at 5 year.
    Date of Submission 2018-02-13

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