| 摘要: | 有機螢光材料由於其特殊的光物理性質，在近年來受到許多的關注，螢光共軛分子因其非侵入性、敏感性、簡單性、快速性，在生物過程及環境科學領域中廣泛應用，像是應用在溶劑態中可用於化學感測器、生物成像；固態可用於有機發光二極體、太陽能電池中的活性層。考慮到螢光分子中電子躍遷至激發態有單光子及多光子激發過程，若同時在單光子及多光子吸收都能夠有良好的表現，將可拓展其應用。有機雙態螢光發射是一個全新的主題，是指在溶液態和固態中保持螢光的分子，由於相互排斥的幾種現象，這種現象曾被認為很罕見，必須在多個非輻射因素與螢光機制競爭之間達到微妙的平衡。開發雙態螢光與多光子吸收分子的重要性在於同一分子可以用於不同的目的，這大幅增加了螢光材料在應用中的效率。
根據過去研究以及文獻探討，在本文中開發了兩種以苯並三唑及三唑結構單元為核心的螢光分子，針對其在溶劑態與固態進行吸收、螢光光譜的線性光學量測，與溶劑態非線性飛秒時域之雙光子激發截面光譜的量測。在部分分子中引入嗎啉官能基團，在經由細胞實驗後證實能夠標記細胞中的溶酶體，說明此類分子應用於生物成像的潛力。其中，模型分子(3)更能夠精準的標記細胞中的溶酶體，具有相對較好的專一性，且在固態螢光發射測得最大量子產率（ФF = 0.44），有成為雙態發射材料的潛力；模型分子(2)同樣在溶液態與固態都有良好的量子產率，分別為ФTHF = 0.96, ФSolid-state = 0.35，且在雙光子吸收也有良好的吸收截面（δ = 495 GM），可作為高效的螢光材料。
我們在對非對稱之苯並三唑進行烷化反應時，會得到取代位置不同的三種異構物，其中官能基使用強的拉電子基團，對於8號、9號位的碳在核磁共振光譜中會有明顯且可供辨識的化學位移差異，利用管柱層析法與結構光譜作為鑑定依據，在本文中成功分離非對稱型苯並三唑與烷氧基碳鏈進行烷化後的三種異構物，並個別對三種異構物之光譜鑑定分析，為後續分子設計建立合成及純化方法的基礎。
;Organic fluorescent materials have received significant attention in recent years due to their unique photophysical properties. Fluorescent conjugated molecules are widely used in various fields such as bioprocesses and environmental science due to their non-invasiveness, sensitivity, simplicity, and fast response. They find applications in chemical sensors and biological imaging in solution phase, as well as in organic light-emitting diodes and active layers of solar cells in solid-state. Considering that electron transitions to the excited state in fluorescent molecules can occur through both single-photon and multi-photon absorption processes, achieving good performance in both single-photon and multi-photon absorption can expand their applications. Organic dual-state fluorescence emission is a novel research topic, referring to molecules that exhibit fluorescence in both solution and solid-state. This phenomenon was once considered rare due to several competing non-radiative factors in both solution and solid phases, requiring a delicate balance between these competing factors through appropriate molecular design. The importance of developing dual-state fluorescence and multi-photon absorbing molecules lies in the fact that the same molecule can be used for different purposes, significantly increasing the usefulness of fluorescent materials in applications.
Based on previous research and literature search, this study developed fluorescent molecules based on benzotriazole and triazole structural units, focusing on their linear optical measurements of absorption and fluorescence spectra in solution and solid-state, as well as their two-photon absorption spectra in solution within femtosecond regime. The introduction of morpholine functional groups in some of the molecules was found to enable the labeling of lysosomes in cell experiments, demonstrating the potential of such molecules for biological imaging. Among them, model molecule 3 is capable of labeling lysosomes in cells with better specificity and exhibits the highest quantum yield in solid-state fluorescence emission (ФF = 0.44), showing potential as a dual-state emitting material. Model molecule 2 also demonstrates good quantum yields in both solution and solid-state, with ФTHF = 0.96 and ФSolid-state = 0.35, respectively. Additionally, it exhibits strong two-photon absorption with a high absorption cross-section (δ = 495 GM), making it a promising candidate for efficient two-photon fluorescence material.
In addition, we also tentatively explore the synthesis and separation of structural isomers of alkylated benzotriazoles. During the alkylation reaction of asymmetric benzotriazoles, three isomers with different substitution positions are obtained. The use of strong electron-withdrawing functional groups at C-X position results in significant difference in chemical shifts of the C-8 and C-9 in the NMR spectra. By using column chromatography and structural spectroscopy for identification, we successfully separated the three isomers obtained from the alkylation of asymmetric benzotriazoles and conducted spectral analysis of each isomer, establishing a useful standard procedure for the preparation of these isomers which would be beneficial for the future molecular design. |
