| 摘要: | 發光基團決定了分子的顏色，意即吸收特定紫外-可見光波段和使互補波段透射或反射。在本論文中，我們關注的是π-共軛多環芳香系統中，具有異原子架構的發光基團。多環芳香烴化合物(PAHs)，可以看成是石墨的一個小單位，能利用在各種不同的有機電子元件上。在過去幾年中含氧原子的benzo[5,6]naphthaceno[1,12,11,10-jklmna]xanthylium (BNAX)鹽類化合物成功的被合成出來。這些帶正電的PAHs具有優良的紫外-可見光區的吸收。
在目前初步階段，BNAX鹽類化合物的製備過程，還未能達量產及最佳化。本論文主要聚焦在改進共三步驟的合成效率及製備衍生物。依據目前文獻製備化合物BNAX 是從Claisen縮合反應，再經過溴化反應，最後是照光氧化合環反應。我們把具有拉電子或吸電子性質的官能基取代到PAHs的架構上。在本論文中，我們採用具有磺酸基的離子液體當成催化劑，無須添加溶劑，讓反應物直接反應，來替代強酸混合弱酸的反應系統，進行Claisen縮合步驟；此離子液體不僅能重複使用共七次，且產率也有所提昇。
在照光環合的反應中，我們利用照射太陽光來進行氧化環合，此系列BNAX衍生物反應皆可在三個小時內完成。
A chomophore is the part of a molecule responsible for its color, i.e., absorbing certain UV-Vis wavelengths and transmitting or reflecting the complimentary wavelengths. In this dissertation, the chromophore of interest has a π-conjugated polycyclic aromatic system with heteroatoms in skeleton. Large polycyclic aromatic hydrocarbons (PAHs), as subunits of graphene, have been exploited in various organic electronic devices. It became possible for step by step synthesis of the O-containing benzo[5,6]naphthaceno[1,12,11,10-jklmna]xanthylium (BNAX) dye in recent years. These positively charged PAHs exhibit nice UV-Vis absorption bands.
As preparation of BNAX salts is still at its infant stages, the whole process has not yet been scaled nor operationally optimized. The dissertation herein is mainly concerned with the improvement of multiple stage synthesis and the preparation of derivatives. Currently the literature synthesis of BNAX starts with Claisen condensation, followed by Br2 oxidization, and finalized with oxidative photocyclization. Substitution on PAHs with electron releasing or electron withdrawing groups have been realized.
In this dissertation, we used the sulfonic group attached ionic liquid as catalyst under solvent-free condition to replace the mixed strong acid weak acid system to do the Claisen condensation. The ionic liquid route not only increases the yield, but also serves as recoverable and reusable catalyst for 7 times without decrease in yield.
In the oxidative photocyclization reaction, we used sunlight to finalize to the synthesis of BNAX derivatives. All the reactions were found to complete in three hours. |
