| 摘要: | II 中文摘要 系列一：合成出一系列bis-(1,3,4-oxadiazoles)的有機液晶分 子。所得之化合物經由1H- 和13C-NMR 光譜及元素分析(EA)加以鑑定 及結構與純度。而液晶現象的觀察，藉由熱差式掃瞄卡計儀(DSC)和 偏光顯微鏡(POM)來判斷。實驗結果顯示，不論其為meta 位置或para 位置之化合物，當側鏈基數目為6 時，均為Colh液晶相。然而meta 位置之化合物，當側鏈基碳數為8 至16 都是Colh液晶相，且液晶相 溫度範圍較寬廣，流動性也較佳。除了研究液晶相關性質，也做了一 些其他物性之探討。 系列二：合成一系列salicylaldimine 之配位基，此配位基在與 金屬(Pd、Cu)配位，形成錯合物。實驗結果得知，側鏈取代基為拉電 子基且接近苯環，會使液晶相溫度範圍縮短。進而發現，改變中心硬 段部分而合成benzoxazole 之錯合物，當側鏈基含有萘環時，其具有 N 液晶相。 In this work two series of heterocyclic compounds in which two unsaturated five-membered ring based on 1,3,4-oxadiazole utilized as the core center were generated and their mesomorphic properties investigated. Some of this type of oxadiazole-based materials have been studied and found to show novel properties, and these physical studies were focused on electron-transporting capability or photoconducting for advanced electronic devices. However, examples of mesomorphic 1,3,4-oxadiazole derivatives were relatively scarce. 1,3,4-oxadiazole derivatives were though considered as one of non-linear mesogenic compounds. Here we report the first example derived from bis(1,3,4-oxadiazole) that exhibit a columnar phase. Results indicated that all derivatives of 1,4-bis[2-(3,4,5 -trialkoxylphenyl)-1,3,4-oxadiazol-5-yl]benzenes and 1,3-bis[2-(3,4,5 -trialkoxylphenyl)-1,3,4-oxadiazol-5-yl]benzenes were columnar mesophases. |
