由具噻吩之彎曲單元組裝不同幾何結構之液晶材料

淡江大學機構典藏 > 理學院 > 化學學系暨研究所 > 學位論文 > Item 987654321/32682

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題名:	由具噻吩之彎曲單元組裝不同幾何結構之液晶材料
其他題名:	Liquid crystals from various geometrical assemblies of bent thiophene-containing moieties
作者:	洪俐綺;Hung, Li-chi
貢獻者:	淡江大學化學學系碩士班徐秀福;Hsu, Hsiu-fu
關鍵詞:	氫鍵;彎曲形液晶分子;bent-shaed molecules;hydrogen bend
日期:	2007
上傳時間:	2010-01-11 02:33:06 (UTC+8)
摘要:	系列一部分為在六炔苯基苯盤形分子上引入一對位吡啶炔側臂，在與引入鄰位、間位的分子相比較後，發現含對位吡啶炔側臂的化合物其澄清點溫度最低且無熱分解問題。系列二中利用在噻吩2、5位置上引入不同取代基形成彎曲分子，組裝不同幾何結構的液晶分子。其中一端接上具高極性的吡啶炔基或含氰苯基，而另一邊則接上炔苯基或聯苯炔基，具聯苯炔基的彎曲分子具有較好的液晶性質。另外，在中心苯環外接六個噻吩炔苯側臂所形成的盤形分子則可形成穩定的具盤形向列相。系列一、二中所合成的具對位吡啶炔側臂的液晶分子利用氫鍵與具酸根分子形成不同幾何形狀之液晶材料，並以偏光顯微鏡、熱微差分析儀、核磁共振光譜儀鑑定其氫鍵及液晶性質。所生成的氫鍵複合物其液晶形成溫度及澄清點溫度皆比原化合物來的低。　　In the first part, one of the side-arms of hexakis(alkoxylphenylethynyl)benzene was replaced with a 4-pyridinylethynyl group. Comparing with analogous compounds incorporating a 2- or 3-pyridinylethynyl moiety, the compound with a 4-pyridinyl -ethynyl unit shows lowest melting and clearing points. Bent-shaped and discotic thiophene-based liquid crystalline materials are reported in the second part. For bent shaped liquid crystals, polar groups, pyridinylethynyl or benzonitrilethnyl, was incorporated into one end of the thiophene unit while a biphenylethynyl or a phenylethynyl unit was attached to the other end. Compounds with a biphenylethynyl unit were found to have better mesogenic properties than the phenylethynyl analogues. In addition, a newly prepared disc-like molecule with six (hexyloxyphenylethynyl)thiophene shows superior discotic nematic behavior than traditional hexaynylbenzenes. Liquid crystalline molecules with 4-pyridinylethynyl reported in the first and second series and benzoic acid derivatives were assembled via hydrogen bond formation to afford liquid crystalline materials with various molecular geometries. Hydrogen-bonded complexes show lower melting and clearing points than their original components.
顯示於類別:	[化學學系暨研究所] 學位論文

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