含2,4,6-三取代吡啶及喹喔啉雜環單元之染料分子的合成與其光學性質探討

Synthesis and Optical Properties of Novel Heterocyclic Chromophores Derived from 2,4,6-Triaryl Pyridine and Quinoxaline Units

李玫璘(Mei-Ling Li)

指導教授 ： 林子超

國立中央大學/理學院/化學系/碩士(2015年)

摘要

本論文主要經由Chichibabin pyridine synthesis和縮合反應合成出一系列含有吡啶及喹喔啉兩種雜環單元之非對稱型樹狀模型分子，藉由改變模型分子中的推/拉電子基團種類以探討模型分子結構的改變對其光學性質的影響。由線性光學實驗量測模型分子之最大吸收波長、最大放射波長、螢光量子產率及螢光生命期；非線性光學使用飛秒時域之脈衝雷射進行雙光子激發螢光光譜圖實驗，再利用螢光比較法換算出各模型分子之雙光子吸收截面值，並歸納出以下結論:
1.不對稱型樹狀結構具有明顯的溶劑效應。
2.延長分子前端fluorene取代基之共軛長度及增加分子外圍之推電子取代基數目可增進π-電子非定域化範圍，亦有助於提高雙光子吸收效能。
3.以2,4,6-三取代吡啶為核心其整體共平面程度並沒有很好，導致π-
電子非定域化範圍局部受限，亦影響此系統模型分子之雙光子吸收
整體表現。

關鍵字

雙光子吸收材料 ； 有機合成

並列摘要

A set of novel unsymmetrically substituted and multi-branched chromophores containing pyridine and quinoxaline heterocyclic rings has been synthesized via Chichibabin pyridine synthesis and condensation. The results from linear optical property measurements show that these chromophores possess strong solvent effect on their fluorescence emission and lifetime behaviors. These model compounds also exhibit strong and broadly-dispersed two-photon absorptivities in the near infrared (NIR) within the spectral range of 680nm-1080nm. It is demonstrated that chromophores with more electron-donors and extended π-conjugation would exhibit stronger nonlinear absorptivities. It is also revealed that these 2,4,6-triaryl pyridine–based chromophores do not possess good coplanarity, which leads to limited π-electron delocalization and may hamper the molecular two-photon absorption.

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