爪型液晶及含雙雜環有機液晶材料之合成與研究

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/60551

Title:	爪型液晶及含雙雜環有機液晶材料之合成與研究
Authors:	林彥君;Lin,Yen-Chun
Contributors:	化學學系
Keywords:	爪型液晶;雙雜環液晶
Date:	2013-07-23
Issue Date:	2013-08-22 11:40:22 (UTC+8)
Publisher:	國立中央大學
Abstract:	本篇論文主要分成兩系列。所有化合物經由1H-NMR、13C-NMR與元素分析鑑定其結構及純度；液晶相性質則分別利用光學顯微鏡POM觀察其相的種類、使用熱微差掃描分析儀DSC測量其相變化時的溫度與熱焓值，最後使用變溫X-ray粉末繞射儀，再次確認液晶相種類，並推測其分子排列與推疊情形。系列一的實驗主要為合成與研究polycatenar液晶材料1a-1d，其結構為：四個芳香環組成的硬端中心，外圍連接兩條、四條或六條軟端烷氧鏈。烷氧鏈的數目與(或)位置影響此類化合物的液晶相變化。除此之外，固定外圍烷氧鏈數目與位置，合成化合物2a-2d，觀察延長中心硬端長度時的相變化，嘗試歸納分子結構與液晶性質之間的關聯性。系列二合成具有雙雜環Isoxazole及Pyrazole結構之有機液晶分子。探討當烷氧鏈為不同碳數時(n = 8、10、12、14、16)對液晶相的影響。成功養出同樣碳鏈長度n = 6三種化合物4b、5b及6b的單晶(含雙雜環Isoxazole、Pyrazole及合環反應之前驅物)，藉用X-ray單晶繞射分析的數據，探討分子間的作用力與平面性。 In this work, two series of mesogenic compounds were prepared and studied. All compounds were characterized and identified via 1H-NMR, 13C-NMR, mass analysis and elemental analysis. The mesophases were studied and investigated by POM and DSC, and the structures of the mesophases were also confirmed by variable temperature X-ray diffraction experiments. In the first series, mesogenic compounds 1ad were synthesized and their mesomorphic behavior investigated. These fourrings aromatic compounds, considered their molecular shapes as polycatenar mesogens attached with two, four or six terminal flexible aliphatic chains exhibited interesting mesomorphic behavior. Compounds 2ad with an extended aromatic ring as central core were also prepared and studied. The formation of mesophases was found to be sensitive to the number and/or positions of alkoxy chains. The correlation between the molecular structures and the mesomorphic properties will be discussed. In the second series, a new type of mesogenic heterocyclic compounds derived from bisisoxazoles and bispyrazoles 46b were prepared and studied. Both heterocycles were considered as electron-deficient. Their mesomorphic behavior was dependent on the carbon lengths attached. A single crystal Xray determination was resolved and molecular interactions on the effect and/or formation of mesophases in these compounds were studied in details
Appears in Collections:	[Graduate Institute of Chemistry] Electronic Thesis & Dissertation

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