- 學位論文
六苯并寇液晶材料的合成、六炔苯基苯筒型液晶材料手性放大及引入高偶極對盤狀向列液晶原之影響
Syntheses and Chiral Induction in Columnar Liquid Crystalline Phases of Hexabenzocoronene, Hexakis(phenylethynyl)benzene Derivatives and the Effect in Discotic Nematic Liquid Crystal by Introducting Large-Dipole Group.
摘要
本論文主要將兩種盤狀液晶之中心硬核：六苯并寇及六炔苯基苯，分別對其衍生物的合成、液晶性質進行探討。 第一部分為六苯并寇衍生物的結構設計與合成，設計以長短鏈交錯且以C3對稱的方式引入環己烷，希冀其能因結構設計所產生的立體效應而使中心核有較大的有效接觸面積，以提高筒內單位面積之電流密度，並利用長短鏈所產生之似齒輪結構設計，使其有大面積的有序排列。 第二部分對於引入不同數量掌性側鏈於六炔苯基苯液晶核對於手性放大的影響。利用掌性盤狀分子誘導非掌性筒柱形成對掌性筒柱的概念進行摻混，並利用圓二色光譜儀找出引入具旋光中心的對掌性鏈數與最小摻混量間的關係。 第三部分為將盤狀向列型液晶的六炔苯基苯的其中一苯烷基以強偶極氰苯基或氰聯苯基取代，以了解此高偶極氰基對分子間排列的影響。強偶極氰基的引入使原較散亂的盤狀向列型排列轉換成規則性高的筒型排列。
並列摘要
The aim of this thesis is to explore the synthesis and liquid crystal properties of hexabenzocoronene and hexakis(phenylethynyl)benzene. The first part includes the design and synthesis of hexa-peri-hexabenzocoronene-(HBC)-based derivatives. It was attempted to introduce cyclohexyl group in a C3 symmetry manneto increasee effective interdisc contact area for higher charge mobility intra-columnar. The second part discusses the chiral amplification effect by introducing various number of chiral side chains onto hexakis(phenylethynyl)benzene. The results by circular dichroism (CD) spectroscopy indicate a liner relationship between the number of chiral chains and the minimum chiral dopants are determined. The third part explores the influence on supra-structures by replacing a alkylphenyl with a a polar cyanophenyl or a cyanobiphenyl group onto the discotic nematogenic hexaynylphenylbenzene. The polar cyano group in either case induced the columnar molecular packing.