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標題: | I.雙邊胍基修飾具有聚集誘導放光性質的順式與偕式四苯乙烯分子骨架以作為偵測去氧核醣核酸之螢光探針並探討去氧核醣核酸的二級結構變化 II.胍基與磷酸基修飾四苯乙烯應用於自我組裝誘導發光超分子 I. Cis- and Gem-Guanidinium Functionalized AIE Tetraphenylethylene Scaffolds: Two Novel Fluorescent Probes for DNA Sensing and the Exploration of DNA Secondary Structure Transitions II. Guanidinium- and Phosphate-Tethered Tetraphenylethylene for the Application in Self-Assembly of AIE-Active Supramolecules |
作者: | 吳奇樺 Chi-Hua Wu |
指導教授: | 陳昭岑 Chao-Tsen Chen |
關鍵字: | 胍基,磷酸基,聚集誘導發光,核酸,分子辨識,四苯乙烯,超分子自組裝, guanidinium,phosphate,aggregation-induced emission,nucleic acids,molecular recognition,tetraphenylethylene,supramolecular assembly, |
出版年 : | 2023 |
學位: | 碩士 |
摘要: | 胍基 (guanidine) 作為有機超強鹼以及具有高平面特性的Y型結構,能提供雙牙基氫鍵以及正電荷,與幾何互補的磷酸根產生較強的非共價鍵結合。本論文包含兩部分的研究:第一部分在具有聚集誘導放光性質的四苯乙烯骨架上,分別於順式 (cis-form) 以及偕式 (gem-form) 引入兩個胍基 (cis-2G/gem-2G,圖 1),藉此調控雙胍基的間距,以探討胍基與不同DNA之間的作用模式,並作為標靶DNA的螢光分子探針,同時與不受間距效應影響的單胍基型cis-1G以及多胍基型TPE4G進行比較。第二部分實驗則發展具有磷酸基的四苯乙烯衍生物 (cis-2P/TPE4P) 作為建構單元,與具有胍基的四苯乙烯衍生物 (cis-2G/TPE4G) 或是鈣離子形成不同結合比例的自組裝誘導發光超分子,並期許能分別作為氫鍵有機框架材料以及金屬有機框架材料,以應用於氣體儲存等領域。
雖然單晶結果顯示gem-2G的雙邊胍基相比於cis-2G有較大的間距,實驗證實兩化合物的胍基仍可分別與單股、雙股以及鳥嘌呤四股DNA,透過多重氫鍵與靜電吸引力相互結合並誘導出不同的DNA二級結構轉變,並伴隨吸收波段的紅移、聚集誘導螢光強度的增加、以及圓二色光譜訊號產生變化,其結合常數達104-105 M-1。此外,cis-1G以及TPE4G同樣具有結合DNA的能力。由Job plot進一步得知,cis-2G的胍基與DNA磷酸根的結合計量比約為1:1,相較之下,gem-2G則呈現較低的DNA飽和當量數,推測是雙邊胍基的間距差異所致。最後由細胞與電泳實驗證實cis-2G能作為偵測DNA的螢光分子探針。接續分析cis-2G與雙磷酸鹽藥物 (BPs) 的結合能力,發現當cis-2G結合BPs後會導致其單體螢光強度與吸收度的下降,也藉由氫核磁共振光譜滴定實驗觀察到些微去遮蔽效應,證實cis-2G能結合雙磷酸鹽藥物,並推測雙磷酸鹽藥物的胺基可能同時與cis-2G的冠狀醚以及四苯乙烯分子骨架產生作用。 第二部分實驗成功合成具有雙邊以及四邊修飾磷酸基的四苯乙烯衍生物 (cis-2P/TPE4P),能透過與胍基修飾的四苯乙烯建構單元 (cis-2G/TPE4G) 產生多重氫鍵,以自組裝形成不同四苯乙烯結合比例的氫鍵有機超分子 (圖 2);或是透過與鈣離子自組裝產生金屬有機超分子 (圖 3)。其中,在水溶液的條件下,由螢光結合等溫線可觀察到cis-2P/cis-2G超分子為1:1比例配對;cis-2G/TPE4P以及cis-2P/TPE4G的結合比例為2:1;而TPE4P/TPE4G/cis-2G則以2:2:1.5比例配對,同時四組超分子的螢光強度也會伴隨四苯乙烯建構單元的比例增加而提升。另外,cis-2P/TPE4P也能分別與鈣離子自組裝以形成超分子結構。最後,利用電子顯微鏡鑑定這些超分子並觀察到其各具有不同的型態。綜合相關實驗,說明溶劑以及濃度的選擇皆是影響這些超分子自組裝的重要因素。 Guanidine is categorized as an organo-superbase. Due to the highly basic nature and symmetric Y-shaped structural features, guanidinium groups can provide two parallel hydrogen bonds and electrostatic interactions with phosphonate derivatives to form strong ternary structures. This thesis can be divided into two parts. In the first part, two guanidine groups are introduced in cis-form and gem-form respectively on the molecular skeleton of tetraphenylethylene (cis-2G/gem-2G in Figure 1) with aggregation-induced luminescent properties. By adjusting the distance between guanidine groups, the interaction mode between guanidine groups and different DNAs can be explored which can be developed as DNA fluorescent molecular probes and compared with cis-1G/TPE4G cases. In the second part, we also develop self-assembly-induced luminescent supramolecules with different ratios of tetraphenylethylene derivatives containing phosphate groups. Based on the remarkable non-covalent interactions of guanidinium-phosphate ternary complexes, this study also synthesizes phosphate-tethered TPE scaffolds (cis-2P/TPE4P) to form hydrogen-bonded supramolecules with different ratios of cis-2G/cis-2P/TPE4G/TPE4P units or with calcium ions to form metal-bonded supramolecules via self-assembly processes. These TPE-based supramolecules are explored for applications as gas storage demonstrates the potential to construct hydrogen-bonded organic frameworks (HOFs) or metal-organic frameworks (MOFs). Although the single-crystal structural analyses show that the bilateral guanidine groups on gem-2G have a larger distance than cis-2G, the guanidine groups on both gem-2G and cis-2G can induce single-stranded, double-stranded, and G-quadruplex DNAs, respectively, to form different DNA secondary structure changes via hydrogen bonds as well as electrostatic interactions. These recognition events result in aggregation-induced fluorescence (AIE), a red-shift absorption, and a signal change in the circular dichroism spectrum. The binding constant is about 104-105 M-1. Moreover, cis-1G/TPE4G also shows the ability to bind with DNAs. The Job plot further reveals that stoichiometry between the guanidinium groups of cis-2G and phosphate groups is about 1:1, and gem-2G has a lower number of DNA saturation equivalents, which is presumably caused by the difference in the distance between the bilateral guanidine groups. According to cell images and Native PAGE gels, we also prove that cis-2G can serve as a fluorescent probe for detecting DNAs. In addition, in the titration experiment between cis-2G and a bisphosphonate drug (BPs), it was found that both the fluorescence intensity and absorbance of cis-2G decreased, and a downfield shift of cis-2G was observed in 1H NMR spectra, indicating that the ammonium group of BPs is possibly involved in the interaction with crown ether and TPE unit of cis-2G and the bisphosphate groups form multiple hydrogen bonds with the guanidinium groups. To attain HOFs, two tetraphenylethylene molecules modified with phosphate groups on the four sides (TPE4P), and tetraphenylethylene with double-sided phosphate groups (cis-2P) are synthesized and used as building blocks to explore the feasibility of forming self-assemblies of TPE-based supramolecules with multiple hydrogen-bonding interactions or calcium ions coordination (Figure 2, 3). The fluorescence experiments under aqueous conditions revealed that cis-2P/cis-2G supramolecular pairing is found to be 1:1; both TPE4G/cis-2P and TPE4P/cis-2G is 1:2; TPE4P/TPE4G/cis-2G is 2:2:1.5 pairing. Concomitantly, the fluorescence intensity of the supramolecular assemblies is increased with the increase of the tetraphenylethylene units. Furthermore, cis-2P and TPE4P can form supramolecules with calcium ions. These supramolecular morphologies are further confirmed by SEM and TEM images. In conclusion, the experiments show that the choice of solvents or concentrations plays an important role in supramolecular assembly. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/91195 |
DOI: | 10.6342/NTU202304483 |
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顯示於系所單位: | 化學系 |
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