- 學位論文
鹵素鍵引發咪唑—口引口朵偶聯物的自組裝研究及其光物理性質研究
Halogen bonding triggered the self-assembly of imidazole-indole conjugates and thier photophysical properties
摘要
本研究重點為以鹵素原子修飾聚集誘導發光分子產生之光物理性質研究。聚集誘導發光分子打破傳統螢光分子的思維且兩者發光機制正好相反，而研究此領域之團隊逐年增加，使此材料成為重點科學。在此研究中使用三苯咪唑與吲哚作為分子主要架構。三苯咪唑為典型聚集誘導發光系統之分子，同時扮演共軛分子中的電子供體（D）；吲哚於此分子中扮演電子受體（A）的角色，以乙烯橋（π）連接兩分子使形成D-π-A系統。此系統有利於分子內電荷轉移，產生吸收光譜以及螢光光譜紅移的現象。引入不同的官能基使調整能階高低可改變分子螢光顏色，使其在光電材料應用上更加豐富。此外，鹵素鍵的研究與應用亦為近年來之熱門研究話題。可利用鹵素鍵來調整螢光波長或分子排列達到自組裝性質。在吲哚端接上鹵素原子，包含氟、氯、溴以及碘等原子形成此篇一系列之分子，分別為TPIIF、TPIIC、TPIIB與TPIII，並與未取代之分子TPIIH進行比較。將此系列分子溶於不同溶劑，發現TPIIF和TPIII在哌啶中分別呈現白色與淡黃色螢光，而其他分子呈現藍色螢光。然而在其他非含氮溶劑中，TPIIX（X= H, F, C, B, I）在相同溶劑下顯示的螢光並無太大差異，可以推測哌啶中氮原子容易與氟或碘形成鹵素鍵。此外，TPIII在苯甲腈與哌啶溶劑中發現自組裝的現象，可進一步推測鹵素鍵的存在。而此研究策略達成單分子白光之現象，於是進行鹵素鍵之研究。
並列摘要
The study is about the change of photophysical properties on modifying aggregation-induced emission (AIE) molecules by halogen atoms. AIE molecules broke with traditional dyes with opposite fluorescence mechanism, and thus numerous research groups focused on this domain. Herein, we introduced diphenylimidazole and indole to our design of AIE molecules. Diphenylimidazole with specific AIE characteristic and also played the role of electron donor in the conjugated system. On the other hand, indole acted as an electron acceptor and conjugated with diphenylimidazole through vinylene π-bridge to form D-π-A system which is benefit for intramolecular charge transfer (ICT). The emission color could change by introducing different functional groups to modifying energy gap, making it promising for photoelectric field. Moreover, the research of halogen bonding has gained more attention in recent years. Halogen bond affected photophyical properties and the molecular arrangement caused self-assembly. We replaced a hydrogen atom form indole with halogen atoms to form a series of imidazole-indole conjugates called TPIIX (X= H, F, C, B and I) in this study. TPIIH with unsubstituted indole; TPIIF, TPIIC, TPIIB and TPIII corresponded to fluoride, chloride, bromide and iodide, respectively. Their optical properties were similar in same solvents which are not nitrogen containing solvents. However, TPIIF and TPIII shown white and light yellow emission in piperidine, respectively; while others shown blue emission. We assumed that fluorine and iodine atoms tended to form halogen bond with nitrogen atom from piperidine accompanied by the emission color changed. In addition, we observed TPIII with self-assembly property in benzonitrile and piperidine, which further testified the presence of halogen bonding. The results demonstrated single-molecular white-light emission (SMWLE) in our tactics and thus carried out research on halogen bonding.