| 摘要: | 本篇論文分為兩個系列，其中系列一設計出以對苯二甲酸二甲酯為中心並含有異唑及吡唑之不對稱異雜環化合物 1c、配位基 2c 及其硼錯合物 2c-BF2。此外，將中心結構改變為 2,5-吡啶二甲酸甲酯合成出化合物 2a、2b 及其硼錯合物 2a-BF2 。利用偏光紋理圖及繞射圖譜之特徵峰確認化合物 1c (n = 8, 10, 12)、2b (n = 8, 10, 12)、2c (n = 8, 10, 12) 及 2c-BF2 (n = 8, 10, 12) 皆為盤狀液晶 Colh 相；而 2a (n = 12, 16) 為桿狀液晶層列型 C (SmC) 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。此外，為討論化合物的光物理性質，從紫外/可見光吸收光譜及光致發光光譜之結果可得知，化合物2c-BF2 (n = 12) 的最大放光波長在此系列中波長最長 (λmax = 523 nm)，而在固態螢光光譜中化合物2-BF2之放光波長皆比在溶液中紅位移，此為 J-aggregate現象所致。
系列二是以對苯二甲酸二甲酯為中心，以 tetraketonate 連接含苯環及外圍烷氧鏈，成功合成出配位基 4a、4b，並與二氟化硼配位形成錯合物 4a-BF2、4b-BF2。透過偏光紋理圖及熱微差掃描分析儀，判定 4a、4b、4a-BF2 及 4b-BF2 (n = 12) 皆不具有液晶相。從紫外/可見光吸收光譜及螢光光譜結果得知，可發現化合物4-BF2的放光波長皆比化合物4來得紅位移，而化合物4c-BF2 (n = 12) 的最大放光波長在此系列中波長最長 (λmax = 576 nm)。
;This study was divided into two series. In series 1, the liquid crystal material 1c with dimethyl terephthalate as the center, five-membered heterocyclic rings isoxazole and pyrazole on both sides and its ligand 2c was designed. Another material 2c-BF2 with isoxazole and boron difluoride was also designed. Furthermore, compounds 2a, 2b, and 2a-BF2 were designed which the center was changed into 2,5-pyridinedicarboxylate. With polarized optical microscope (POM) and X-ray diffraction (XRD), it was confirmed that 1c (n = 8, 10, 12), 2b (n = 8, 10, 12), 2c (n = 8, 10, 12) and 2c-BF2 (n = 8, 10, 12) were enantiotropic columnar hexagonal (Colh) mesophase while 2a (n = 12, 16) were enantiotropic smectic C (SmC) 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). Moreover, the photophysical properties of these compounds were investigated by UV/Vis spectroscometer and photoluminescence spectroscometer. Results appeared that 2c-BF2’s (n = 12) emission wavelength had the highest redshift (λmax = 523 nm) in series 1 which in the solid state were red-shifted compared to in the solution because of the J-aggregate.
In series 2, a new series of boron difluoride complexes 4a-BF2 and 4b-BF2 derived from substituted tetraketonates 4a and 4b with terminal alkoxy groups, containing dimethyl terephthalate as a central core were reported. With polarized optical microscope (POM) and X-ray diffraction (XRD), it was confirmed that 4a, 4b, 4a-BF2 and 4b-BF2 were nonmesogenic. The photophysical properties of compounds 4 were investigated by UV/vis spectroscopy and fluorescence spectroscopy. Results appeared that the maximum emission wavelength of compounds 4-BF2 were found to be higher than the compounds 4 while 4c-BF2’s (n = 12) emission wavelength had the highest redshift (λmax = 576 nm) in series 2. |
