探討末端烷炔鏈對含水楊醛亞胺分子之液晶性質的影響

Study on the Effect of Alkyl Alkynyl Terminal Chains on Mesomorphic Properties of Salicylaldimine-Based Molecules

高仲俊(Chung-Chun Kao)

指導教授 ： 黃俊誠

大同大學/工程學院/化學工程學系所/碩士(2012年)

摘要

我們利用Sonogashira 催化反應將長鏈炔基接入主體為水楊醛亞胺(salicylaldimine)結構中，並以苯酯基(benzoyloxy group)延伸分子共軛，以及加入旋光(R)-2-辛烷基((R)-2-octyloxyl)來探討這些官能基對水楊醛亞胺為主體的液晶相所造成的影響，此研究共分為4大部分：第一部分我們先以炔烷鏈接入水楊醛亞胺中，第二部分則是將第一部分的結構再加入了一個苯酯基，第三部分同樣是修飾第一部分的結構，將一端的末端烷鏈改為旋光(R)-2-辛烷基團使其成為一旋光分子，最後的部分則是將水楊醛亞胺的結構同時導入長鏈炔基、苯酯基和旋光(R)-2-辛烷基。在第一系列的化合物C10YOCn (n = 5-12, 14, 16, 18) 中，同時我們可以發現非旋光長烷鏈較短時(n=5-7)，只有出現層列型A相；長烷鏈延伸至(n = 8-12, 14)，層列型X1相則會出現；繼續延伸至(n = 16, 18)時，會有向列型液晶(Nematic)出現。n = 16有溫度範圍最廣的向列型液晶(N, 27.1°C)。
第二部分的化合物C10YCBOC10有較寬廣的向列型液晶範圍，將近有130°C左右。
第三部分化合物C10YOC8*經由偏光顯微鏡(POM)和熱示差掃描儀(DSC)鑑定結果並沒有任何液晶相生成，而與另一化合物C8*YOC10則是在室溫下為液態。
第四部分的化合物CmYCBOC8* (m=5-10)在m=6和7時擁有最多液晶相，所有化合物均具有膽固醇相(N* phase)、層列型A相(SmA*)、層列型CA相(SmCA*)，並且到室溫時仍為層列型CA相。

關鍵字

炔鍵 ； 誘電型液晶 ； 反誘電型液晶 ； 水楊醛亞胺 ； 希夫鹼

並列摘要

In this study, we introduced the alkyl alkynyl group by Sonogashira coupling reaction, benzoyloxy group and (R)-2-octyloxyl tail into the salicylaldimine core to investigate the mesomorphic properties of salicylaldimine molecules. This works are divided into four sections. The first section is to introduce the alkyl alkynyl into the salicylaldimine core to obtain alkyl alkynyl salicylaldimine molecules. The second series of compounds could be obtained by introducing a benzyloxyl group to extend the conjuation of the alkyl alkynyl salicylaldimine molecules. We introduced (R)-2-octyloxyl tail into the first section of salicylaldimine molecules to obtain the third series of chiral salicylaldimine molecules. The fourth section of salicylaldimine molecules consist of the alkyl alkynyl group, benzoyloxy group and (R)-2-octyloxyl tail were synthesized. In the first section of the compounds, compound C10YOCn (n = 5-7) with shorter alkoxy chain length in the arylamine moiety show only SmA phase. When this alkoxy chain is increased (n = 8-12, 14), unidentified SmX1 phase appear besides SmA phase. However, when alkoxy chain length is further extended, compound C10YOCn (n = 16, 18) show the N and unidentified SmX2 phases. Compound C10YOCn (n = 8) show wider temperature range of the SmC phase (49.8 °C).
The second section of the compounds, C10YCBOC10 in which both alkyl alkynyl and benzoyloxy group are incorporated into the salicylaldimine core, exhibit wider temperature range of nematic phase(130°C).
The third section of the compounds, C10YOC8* show no any mesophase. Another compounds, C8*YOC10, is a liquid at room temperature.
The fourth section of the compound, CmYCBOC8* (m = 6-10) display the N*, SmA* and SmCA* mesophases. Compound CmYCBOC8*(m = 6-7) exhibit frustrated TGBA* phase, and the SmCA* phase still e at room temperature.

並列關鍵字

Schiff base ； salicylaldimine ； alkyne ； ferroelectric liquid crystal ； antiferroelectric liquid crystal

參考文獻

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