Abstract
含矽b,g-烯醛類化合物之電子立體效應及去氧核醣核酸之光化學反應在本論文中被研究及探討. 我觀察了矽基導引cis 及trans醛類化合物脫去ｃｏ的光化學反應機構.含氘之烯醛類化合物經紫外光照射後,生成氘原子保留之烯類化合物,其動力學,同位素效應及可能的光反應的構形在此論文中被求得.由結果中顯示其去碳基之過程為步驟性(stepwize)之反應機制,矽基相對於醛基在trans 的位置,可藉由hyperconjugation的效應,提供較cis指向之相對位置為佳之穩定效果,是基於trans分子可能藉較穩定之反向指向(antiperiplanar)的方式進行反應. Nitrones, 含銠金屬群,有機含鉑金屬化合物及硝基和亞硝基有機化合物在紫外光照下會使形式一去氧核醣核酸造成單股斷裂.利用高解析電泳解析後,顯示其中數個分子具備鹽基位置選擇性切割之能力.去氧核醣核酸切割試劑的光反應機制亦在此論文中被研究,與去氧核醣核酸的交互作用則以接合實驗及電腦模擬實驗得到驗證.這些去氧核醣切割試劑在生物醫學,生化,及分子生物學領域裡將具極高的應用價值.I study the stereoelectonic effect of silicon-containing b,g-enals and the novel controllable photoinduced DNA cleavingprocess by use of nitrones, organometallic complexes (i.e.,ruthenium and platinum metal complexes containing pyridine N-oxide), and organic nitrates and nitriles. The mechanism ofsilicon to direct photodecarbonylation was investigated.Photolysis of deuteriated trimethylsilyl-containing b,g-enals inan ethanolic solution containing potassium carbonate with UVlight produced deuteriated b,g-enals. Their kinetic isotopeeffect, relevant rate constants and the energy of the possibleconformation were well studied. Analysis the results indicatethat the silicon directed the C-CHO bond cleavages in Si-C-C-CHObackbone through deformylation and intramolecular deuteriumrecombination. The overall "carbonyl extrusion" processesinvolve a stepwise mechanism. The trimethylsilyl group trans tothe formyl group provided a greater stabilization effect throughhyperconjugation than the corresponding cis alignment for thedeformylation because of the possible antiperiplanar orientaion.Nitrones, ruthenium clusters complexes coordinated with1-hydoxybenzotriazole and 1-hydroxypyridine-2-thione, andorganoplatinum complexes containing 1-hydroxypyridine-2-thioneas well as phthalimide nitrates and nitrites were studied asphotoinduced DNA cleaving agents. These compounds wereirradiated with UV light to result in the single strand scissionof supercoiled DNA. The results of autoradiogram of thepolyacrylamide gels indicate they can cleave DNA at specificbase moiety. The mechanism and binding process of the DNAcleavage were also studied in this dessertation.