- 學位論文
含pyrazole及isoxazole之有機桿狀液晶
β-Diketone, Pyrazole and Isoxazole Derivatives with Polar Groups: Liquid Crystalline and Thermodynamic Properties
摘要
本篇論文主要包含具有pyrazole結構以及isoxazole結構之有機液晶。所有化合物經由1H-NMR、13C-NMR、Mass與元素分析以鑑定其結構及純度，液晶相性質則是利用偏光顯微鏡(POM)來觀測相種類及熱微差掃描分析儀(DSC)測量相變化時之溫度與熱焓值，最後以變溫粉末X光繞射儀(XRD)確認相的種類。 系列一：合成出具有pyrazole結構的液晶分子，探討不同碳數(n = 8、10、12、14、16) 對液晶相的影響以及在pyrazole上N-H位置取代三種不同官能基，分別為甲基、乙醇基、 啶基，利用取代基賦予不同的分子間作用力，而在化學及物理性質上做探討;合成出具有isoxazole結構之有機液晶，探討不同碳數(n =8、10、12、14、16) 對液晶相的影響; 系列二：合成出具有pyrazole環不對稱結構之有機液晶Hpz-C16-OH，具有SmA相。
關鍵字
有機桿狀液晶並列摘要
In this serie, we report the synthesis, characterization and mesomorphic properties of two series of new mesogenic derivatives based on pyrazole and isoxazole structures. All compounds were characterized by 1H, 13C-NMR spectroscopy and elemental analysis. The phase behaviors of these mesogenic compounds were characterized and studied by differential scanning calorimeter (DSC) and polarization optical microscope. In serie one, a new type of mesogenic compounds derived from heterocyclic pyrazole and isoxazole (Iz-Cn) were prepared and studied. All compounds exhibited smectic phases depending on the carbon length attached. Replacing hydrogen atom of pyrazole by methyl group (Mpz-Cn), ethanol group (Epz-Cn) and pyridinal group (Ppz-Cn) were carried out and the mesomorphic behavior studied. In serie two, we designed and characterized a series of asymmetrical of organic molecules Hpz-Cn-OH derived from pyrazole with one side chains. These compounds exhibited smectic phases.