(1) Theoretical Study of the Effect of Porphyrin-meso-Phenyl Interaction on Oxidation Potential (2) CV Simulation of Hydrogen-Bonding Effect on the Electrochemical Behavior of Phenylenediamines

[[abstract]]本論文包含三大主題,在第一個主題我們觀察到取代基在H2TPP苯環上取代的位置會影響到第一個氧化電位及第二個氧化電位的差值(ΔEox).取代基在H2TPP的para位置時的ΔEox會比取代基在H2TPP的diortho位置的ΔEox小. 在第二個部分,我們從實驗觀察到含有azobenzene取代的紫質有一些獨特的光譜及電化學性質.在光譜方面,含有4個azobenzene取代的五配位鋅紫質的吸收光譜的Q band的吸收鋒有反轉趨勢.在電化學部分,當azobenzene取代基數目增加時,第一個氧化電位越來越正而第二個氧化電位越來越負. 前兩個主題皆以理論計算來解釋,這些實驗所觀察到的現象皆為紫質及取代基之間的共軛強度所造成的. 在第三個部分,我們將phenylenediamine氧化後分別與pyridine及乙醇慘生氫鍵,在此我們以電化學模擬氫鍵產生對phenylenediamine氧化波的影響.[[abstract]]The thesis involves three topics. In the first part, the various values of the difference between the first and second oxidation potentials (ΔEox) for non-metalated meso-tetraphenylporphyrins (H2TPP) are determined by positions of the substituents on the meso-phenyl group. If a substituent is present only at the para position of the meso-phenyl group, ΔEox is generally significantly smaller than those of the H2TPPs with bulky o,o’-substituents on the phenyl group. The second part is concerned with unusual spectral and electrochemical properties of azobenzene-substituted porphyrins. The Q bands intensity ratio (ea/eb) has been reversed by imidazole ligation for zinc porphyrin. Azobenzene causes the anodic shift for the first oxidation potential but cathodic shift for the second oxidation potential for porphyrin free base. These electrochemical and spectroscopic behaviors of porphyrins were elucidated with theoretical calculations and attributed to the extent o f intramolecular ?-conjugation between the central porphyrin rings and the meso-substituents. The third topic is about the ionic hydrogen bonding formation through electrooxidation of a series of phenylenediamines and their interaction with pyridines and alcohols through different patterns. The digital simulation was carried out to fit and understand these experimental voltammograms.[[note]]碩