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標題: | 含酯基香蕉形分子之微波合成方法與取代基對液晶性質之研究 Studies on Microwave Assisted Synthesis and Substituent Effects of Ester Type Banana-Shaped Liquid Crystals |
作者: | Te-Jung Hsu 徐德容 |
指導教授: | 劉廣定 |
關鍵字: | 液晶,微波,取代基,香蕉形, liquid crystal,banana shaped,microwave,substituent, |
出版年 : | 2005 |
學位: | 碩士 |
摘要: | 摘要
本論文主要分為三部分。第一部份探討修飾香蕉形分子之末端苯環對液晶性質之影響:我們設計一系列具不同官能基及改變側鏈之種類或位置的香蕉形分子,以探討其液晶性質。實驗結果發現在末端苯環上接不同取代基後( X = F、NO2、CH3、CN、Cl、OCH3、OC2H5 ),除了接F和NO2 之香蕉形分子具有液晶相之外,接其餘取代基均無法造成液晶相。由此結果可推測,在末端環伸出分子側邊的取代基會明顯地干擾分子的堆疊排列,因而降低液晶相的穩定度甚至導致液晶相被破壞。但接上 F和NO2 則可誘導產生偶極矩,使分子間引力增加,進而產生液晶相。而改變側鏈之種類及位置後則無法使香蕉形分子表現液晶之性質。 此外,我們利用 ”氫鍵 ”取代一般共價鍵,設計一系列氫鍵型香蕉分子,以研究其液晶性質。在液晶性質的探討方面,我們發現連接基的連接方向及其供電子或拉電子的特性確實會影嚮分子的液晶行為。本論文並嘗試以理論計算解釋之。 最後,本論文中嘗試以微波方法取代傳統加熱方式來合成各個目標產物,並且將針對微波與傳統加熱反應對於合成化合物所需溶劑量和反應時間及能量的節省上作比較。 Abstract In the first section of this thesis, we have probed into how the terminal phenyl ring of a banana-shaped molecule affects its liquid crystal property. We have synthesized a variety of banana-shaped molecules with different substituents and altering side chains. Except for F and NO2 groups, other sorts of substituents (including CH3, CN, Cl, OCH3 and OC2H5) would annihilate the liquid crystal character. This outcome reveals that substituents in the terminal phenyl ring would appreciably interrupt the intermolecular stacking and thus diminish the stability of the mesophase even destroy the mesogen’s formation. Nevertheless, F and NO2 groups, by inducing dipoles to increase the intermolecular attraction, would evoke the mesogenic nature. Eventually, neither changing the classification of the lateral side chain nor varying its position would cause a liquid crystal. Moreover, instead of the common covalent bond, we synthesized a series of banana-shaped molecules via hydrogen bonding. We have found that the direction and the electron pulling or pushing quality would indeed influence the liquid crystalline and we have explained this effect through theoretical calculation. At the last, we utilized the microwave to synthesize all the aimed products in place of the traditional heating procedure. Meanwhile, we have compared these two avenues at the points of solvent requirement, time consuming, and energy saving. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/35179 |
全文授權: | 有償授權 |
顯示於系所單位: | 化學系 |
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