降冰片烯衍生物之開環歧化聚合反應
Other Title
Ring Opening Metathesis Polymerization Reaction of Norbornene Derivatives
Date Issued
2004
Date
2004
Author(s)
DOI
zh-TW
Abstract
DNA分子除了具有特殊的雙螺旋結構外，其最重要的性質在於它可以進行複製，而本篇論文的主旨即是在合成雙股高分子，進一步去測試高分子複製的可能性。 在合成雙股高分子方面，其中的一決定因素在於聚合物的排列 (tacticity) 必須有規則性，因此在此合成了一系列不同懸掛基團之降冰片烯衍生物，且利用Grubbs催化劑或Grubbs第二代催化劑對其進行開環歧化聚合反應，經由13C NMR的實驗，發現高分子之立體化學可能是由催化劑的種類及單體分子之結構來決定。 而根據本實驗室先前的研究，擁有非剛性之二茂鐵連接基團經由開環歧化聚合反應後，可得到相對應之雙股高分子，在此引入一剛性的連接基團-平面四方的鉑金屬錯合物來連結兩個降冰片烯衍生物，然後以Grubbs第二代催化劑使其進行開環歧化聚合反應，所得到之高分子，經由XRD的測量可証實此高分子具有某種規則性，EXAFS及固態13C NMR的鑑定可說明單體與開環歧化所得之高分子組成相同，且TGA的測量發現當溫度到達900度C時，只有27%的重量損失，此恰好為雙股高分子中其中一股之重量比率。 統歸這些鑑定結果，此高分子很可能為雙股之結構。 進一步合成了以雙酯類作為連接基團的雙邊降冰片烯之單體分子，經由開環歧化聚合反應後，可得到相對應之高分子，但無法利用水解或還原反應來將此可能之雙股高分子解開成兩個單股高分子，推測原因可能在於所形成之高分子不溶於反應溶劑，因此無法進行反應。 此外，在合成的過程中，我們意外發現可利用Al2O3可進行一種新型態的偶合反應。
DNA molecules are double stranded polymers and the most important property for DNA molecules is replication. Hence, the purpose of this thesis is to synthesize double stranded polymers and further test the possibility to mimic DNA replication. Tacticity plays an important role in synthesizing a double stranded polymer. Hence, a range of polynorbornenes having different pending groups at 2,3-endo position by Grubbs’ ruthenium catalyzed polymerization was synthesized. It appears that Grubbs catalyst has a better selectivity than Grubbs II catalyst towards the tacticity of polymer. In addition, the monomeric norbornenes may also influence the stereochemistry of polymers. According to previous research, bis-norbornene monomer containing ferrocene linking group might lead to the formation of the double stranded polymer. Compared to Ferrocene linking group, the square planar platinum complex is a rigid linking group. It seems likely that the polymer obtained form bis-norbornene monomer containing platinum linking group might also adopt double stranded structure. On the other hand, two monomeric bisnorbornenes containing di-ester linking groups were synthesized for the sake of mimicking the process of DNA replication. The corresponding polymers can be obtained through ROMP. It is envisaged that the hydrolysis or reduction of the ester groups of these polymers might afford two single stranded polymers. Unfortunately, the transformation of theses polymers to the corresponding singe stranded polymers was unsuccessful. The failure might arise from the insolubility of these polymers. Finally, an unexpected reaction has been found during the synthetic process. In the presence of Aluminum oxide, acetic acid 4-dimethylamino-benzyl ester and its related compounds will transform to tetra-N-methyl-4,4’-methanediyl-bis-aniline type products.
Subjects
懸掛基團
氧化鋁
排列
降冰片烯
EXAFS
G(I)
tacticity
G(II)
TGA
XRD
Type
thesis
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