苯胺修飾電極之電流調節應用與敏光性含鈷化合物之光電去溴反應探討

Abstract

由於苯胺衍生物（R-ph-NH2，R = H, ph-N=N-, NH2-）可於與亞硝酸鈉反應時被還原而吸附於電極表面，本論文於是藉由此一特性，先將苯胺及三苯胺等苯胺衍生物偶氮化，再將之還原固定於電極表面上。結果分析顯示：苯胺衍生物似乎以近乎單層、垂直方式附著於電極表面，並可因此將醌類化合物，如苯醌、維生素K3與蒽醌吸附於其中，使之間接被吸附於碳電極表面。我們也發現：利用此一方式所製作的維生素K3修飾電極，對溶液中的pH值變化極為敏感，具有催化還原氧氣之能力，並可與含氯化合物進行錯合反應。此外，我們也發現：被吸附的維生素K3也可作為電子傳遞媒介者，規範電極與電解質溶液間的電子傳遞方向，具電子傳送整流的應用潛力。 本論文也嘗試將含鈷化合物，如Tris(5-aminophenanthroline)cobalt(II) hexafluorophosphate，與胺基芘等感光分子結合，使其成為敏光性的含鈷化合物，藉以模擬維生素B12，進行去鹵化反應（Dehalogenation reaction）。實驗結果顯示：所合成的含鈷錯合物在照光下，可有效還原有機雙溴化合物，如雙溴丁烷（Dibromobutane，簡稱DBB），使之分解成低毒性的衍生物。Aromatic amines can be converted to diazonium salts, and can thus be cathodically deposited on carbon electrodes. In the light of this, we prepared chemically modified electrodes (CME) with aromatic amines, such as aniline and p-terphenylamine, via the diazonium pathway, and utilized them to rectify the flow of electric current from electrodes to electrolyte solutions. Experimental results based on cyclic voltammetry (CV), electrochemical quartz-crystal-microbalance analysis (EQCM), electrochemical impedance analysis (EIS), and totally-attenuated- reflectance Infrared absorption spectral (ATR-IR) analysis indicated that the CMEs prepared in this manner seem to be free of pin holes on the electrode surface, and can, in advance, be employed to microsolvate electron mediators, like benzoquinone (BQ), vitamin K3 (VK3) and anthraquinone (AQ), for further applications, such as for current rectification. Besides, we also attempted to mimic vitamin B12 for the dehalogenation of dibromobutane. Cobalt complexes such as tris(5-aminophenanthroline) cobalt(II) hexafluorophosphate (Co(NH2-phen)32+) show application potential in this aspect. By attaching light-absorption chromophores, like pyrene, with Co(NH2-phen)32+, we, in addition, found that the resultant derivative (denoted py-Co(NH2-phen)32+ ) can be reduced at less negative potential, ca. -0.6 V vs. Ag/AgCl under UV irradiation in DMSO, and then, cause dibromobutane (DBB) to be reductively decomposed into less toxic products.