| 摘要: | 本論文分為三個系列，其中系列一將 1,3,5-三甲基苯三羧酸酯作為核心，以縮合方式連接含苯環及烷氧長碳鏈之結構，成功合成出化合物 1，並將化合物 1 作配位基，與金屬銅形成錯合物 1-Cu，最後將其與二氟化硼形成最終產物 1-Cu-BF2。透過偏光紋理圖以及 X-射線繞射儀之實驗結果，判定化合物 1b (n = 8, 10, 12)、1a-Cu (n = 16)、1b-Cu (n = 8, 10, 12)、1b-Cu-BF2 (n = 8, 10, 12) 皆為盤狀液晶六角筒型 (Colh) 相，以熱微差掃描儀及熱重分析儀，觀察液晶分子在不同溫度下之性質。從紫外/可見光光譜及光致發光光譜之結果可得知，化合物 1b-Cu-BF2 (n = 8, 10) 的最大放光波長在此系列中最長 (λmax = 545 nm)，且隨著烷氧鏈數目的增加，放光波長也有紅移之趨勢。
系列二設計出以 2,5-?啶二甲酸甲酯為中心，同時具有五員雜環異唑及?唑，連接含苯環及烷氧長碳鏈之結構，成功合成出化合物 2a；以及具異唑及二氟化硼的化合物 3a。利用偏光紋理圖及繞射圖譜之特徵峰確認化合物 2a (n = 8, 10, 12) 與 3a (n = 8, 10, 12) 皆為盤狀液晶 Colh 相。以熱微差掃描分析儀觀察相變化之熱焓值，藉此得知其液晶相在不同溫度下的性質表現，並探討五員雜環與含硼錯合物對液晶性質的影響。為討論化合物的光物理性質，從紫外/可見光光譜及光致發光光譜之結果可得知，化合物 3a (n = 10) 的最大放光波長在此系列中波長最長 (λmax = 487 nm)。
系列三將 2,5-?啶二甲酸甲酯作為中心，以單邊縮合並合環?唑，連接含苯環及烷氧長碳鏈，另一側維持酯基之結構，成功合成出化合物 4；將?啶及?唑上的氮原子與二氟化硼配位，得化合物 4-BF2。透過偏光紋理圖以及 X-射線繞射儀之實驗結果，判定化合物 4a (n = 8, 12, 16)、4b (n = 6)、4a-BF2 (n = 8, 12, 16)、4b-BF2 (n = 6, 8) 為桿狀液晶層列型 A (SmA) 相；化合物 4c (n = 12)、4b-BF2 (n = 10, 12, 14, 16) 為盤狀液晶 Colh 相，其中化合物 4b-BF2 具有跨相情形發生，短碳數為 SmA 相，而長碳數為 Colh 相。此外由化合物 4a (n = 8) 及 4b (n = 6) 之單晶結構解析可得知，透過分子間的氫鍵作用力，相互吸引形成二聚體 (dimer)，兩個分子視為一個桿，排列成 SmA 相。從紫外/可見光光譜及光致發光光譜之結果可得知，化合物 4c-BF2 (n = 12) 的最大放光波長在此系列中波長最長 (λmax = 528 nm)。
;This study was divided into three series. In series 1, a liquid crystal material 1 with trimethyl 1,3,5-benzenetricarboxylate as the center, condensated with three diketonates, which contained different numbers of alkoxy groups, were successfully synthesized. Compound 1 was used as a ligand to form complex 1-Cu with metallic copper, and finally the final product 1-Cu-BF2 was formed by coordinated with boron difluoride. With polarized optical microscope (POM) and X-ray diffraction (XRD), it was confirmed that 1b (n = 8, 10, 12), 1a-Cu (n = 16), 1b-Cu (n = 8, 10, 12) and 1b-Cu-BF2 (n = 8, 10, 12) were enantiotropic columnar hexagonal (Colh) mesophase. Furthermore, differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA) were used to observe liquid crystals’ thermal properties. The photophysical properties of these compounds were all investigated by UV/Vis spectroscometer and photoluminescence (PL) spectroscometer. Results appeared that 1b-Cu-BF2’s (n = 8, 10) emission wavelength had the highest redshift (λmax = 545 nm) in series 1.
In series 2, an organic liquid crystal material 2a with dimethyl 2,5-pyridinedicarboxylate as the center, five-membered heterocyclic rings pyrazole and isoxazole on both sides was designed. Another material 3a with isoxazole and boron difluoride was also designed. With polarized optical microscope (POM) and X-ray diffraction (XRD), it was confirmed that both 2a (n = 8, 10, 12) and 3a (n = 8, 10, 12) were enantiotropic columnar hexagonal (Colh) mesophase. The effects of different numbers of alkoxy groups, five-membered heterocyclic ring and boron difluoride complexes on liquid crystals’ properties were also observed by differential scanning calorimeter (DSC). The photophysical properties of these compounds were investigated by UV/Vis spectroscometer and photoluminescence spectroscometer. Results appeared that 3a’s (n = 10) emission wavelength had the highest redshift (λmax = 487 nm) in series 2.
In series 3, an organic liquid crystal material 4 with dimethyl 2,5-pyridinedicarboxylate as the center, one side with five-membered heterocyclic ring pyrazole and the other side maintained its ester group. Compound 4 was used as a ligand to form complex 4-BF2 with boron difluoride. With polarized optical microscope (POM) and X-ray diffraction (XRD), it was confirmed that 4a (n = 8, 12, 16), 4b (n = 6), 4a-BF2 (n = 8, 12, 16), 4b-BF2 (n = 6, 8) were enantiotropic smectic A (SmA) mesophase while 4c (n = 12), 4b-BF2 (n = 10, 12, 14, 16) were enantiotropic columnar hexagonal (Colh) mesophase. Among them, 4b-BF2 had a crossover occurrence, shorter carbon number resulted in SmA mesophase, while longer carbon number were Colh mesophase. The effects of different numbers of alkoxy groups on liquid crystals’ thermal properties were also observed by differential scanning calorimeter (DSC). Two single crystals and molecular structures of mesogenic compound 4a (n = 8) and 4b (n = 6) were resolved. Through the hydrogen bonding force between the molecules, they attracted each other to form a dimer. Two molecules were regarded as a rod and arranged into SmA mesophase. In addition, results appeared that 4c-BF2’s (n = 12) emission wavelength had the highest redshift (λmax = 528 nm) in series 3. |
