合成具螢光輸出訊號香豆素含氮冠狀醚聚胜肽高分子並探討金屬離子誘導之超分子自組裝行為及作為汞奈米粒子合成模板 / 探索含有吡啶配基為側鏈的聚胜肽分子應用於催化反應上的潛力

Synthesis of a New Metal-ion Responsive Azacrown Coumarin Containing Photoluminescent Polypeptide to Investigate the Metal Ions Induced Supramolecular Assembly Behaviors and the Feasibility as the Formation of Mercury Nanoparticle Template / Synthesis and Exploration of Pyridine Containing Polypeptides in the Catalytic Application

王俊翔(Chun-Hsiang Wang)

指導教授 ： 陳昭岑

國立臺灣大學/理學院/化學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201900673

摘要

近年來透過非共價相互作用操控超分子的形成，並模擬生物功能的超分子受到越來越多的關注。使用較強且具方向性相互作用力如金屬－配體配位作用力，可以組裝出具有選擇性、簡單、可逆的聚合物。然而，能即時監測超分子組裝仍具有相當大的挑戰性。因此本研究合成了香豆素含氮冠狀聚胜肽高分子ACCP，藉由螢光變化並結合電子顯微結果來監控聚胜肽高分子自組裝的形成。此聚胜肽高分子是經由活化氨脂 (activated urethane) 衍生物以原位 (in situ) 生成N-羧酸內酸酐 (N-carboxyanhydride) 後開環聚合而成。此合成策略可以避免使用光氣，或具有毒性的光氣衍生物來進行聚合。ACCP與金屬離子錯合物結構的改變可以利用螢光進行即時的監測，當ACCP溶於乙腈時，與銅離子形成錯合物以藍色螢光放射。然而，於三氯甲烷溶液中則對於鈉離子與汞離子有選擇性，此時ACCP中香豆素相互堆積並以激發雙體的黃色螢光放射。此外，ACCP可促進汞奈米粒子於原位生成，於穿透式顯微鏡觀察其大小約為10 nm的實心奈米球體。將汞奈米粒子進一步的應用於貝克曼重排反應，初步結果顯示無法有效催化反應。推測是汞奈米粒子皆包覆於ACCP的保護層內，無法與受質接觸，往後仍需進一步將反應條件最適化，開拓應用端的發展。
啟發於ACCP可誘導汞奈米粒子生成的實驗結果，發展以聚離胺酸作為骨架之聚合物，修飾可與鈀金屬配位的吡啶配基。期望吡啶配基與金屬配位後，利用聚胜肽的立體中心，作為催化反應立體選擇性的來源，同時保有聚合物可重複回收再使用的特性，減少金屬催化劑的使用量，降低對環境的污染。單體因具有吡啶配基，若以原本合成ACCP單體的方法會造成反應所使用的鈀金屬殘留。為了避免此困擾，因此改變合成路徑，合成單體PPy-Lys、MPy-Lys、OPy-Lys與Y-Lys。藉由聚合反應條件的最適化後，發現將單體濃度調控於0.5 M與使用HMPA作為聚合反應之溶劑，可成功合成聚合物PPy-PLL與MPy-PLL。PPy-PLL進一步的應用於丙胺酸之碳－氫活化反應，根據實驗結果無法提升產率，且不具有光學選擇性，未來仍需重新設計配基達到立體選擇的目的。

關鍵字

超分子自組裝 ； 聚胜肽高分子 ； 活化氨酯 ； N-羧酸內酸酐 ； 汞奈米粒子 ； 貝克曼重排反應 ； 碳－氫鍵活化反應

並列摘要

Forming supramolecular assemblies and controlling their behaviors via non-covalent interactions mimicking multi-functional materials have drawn much attention. Utilization of strong and directional interactions such as metal-ligand coordination can achieve spontaneous formation of selective, simple, and reversible supramolecular assemblies. However, it still remains a great challenge to monitor the underlying supramolecular assembly temporally. Herein, a new metal ion-responsive azacrown coumarin-conjugated photoluminescent polypeptide (ACCP) was designed and synthesized via in situ generated N-carboxyanhydride from the corresponding activated urethane monomer to exploit the metal ion-induced supramolecular assembly behaviors. After screening with various metal ions in either acetonitrile or chloroform, the results showed that ACCP˙Cu2+ exhibited blue emission in acetonitrile. However, ACCP dissolved in chloroform displayed strong fluorescence intensity enhancement only in the presence of either Hg2+ or Na+. In the combination of the absorption and the fluorescence profile, the morphologies of ACCP can be deduced. Notably, ACCP can also induce the formation of mercury nanoparticle. The morphologies of the mercury nanoparticle was 10 nm solid nanosphere stabilized by ACCP which was confirmed by transmission electron microscope. ACCP induced mercury nanoparticle was further used as the catalyst in Beckmann rearrangement. The preliminary results show that ACCP induced mercury nanoparticle was unable to catalyze the reaction due to the fact that the mercury nanoparticle was encapsulated compactly in the interior of the polymersome, rendering the mercury nanoparticles not accessible to the substrates. Further optimization of the reaction condition is required.
Inspired by the ACCP induced mercury nanoparticle, polypeptide containing the pyridine ligands were designed and synthesized. Taking the advantage of the chirality in the polypeptide and the immobilization of the palladium via pyridine ligands, it is hoped to achieve good stereoselectivity in the synthesis of unnatural amino acid and the recover the palldium. A new synthetic strategy was developed to synthesize polymerizable monomer with the pyridine ligand to mitigate the contamination of the palladium needed to used in the original strategy. Based on this strategy, PPy-Lys, MPy-Lys, OPy-Lys, and Y-Lys were successfully synthesized, PPy-PLL and MPy-PLL were obtained in good yield with molecular weight around 8 kDa. PPy-PLL was further used as a ligand to C-H activation. The results revealed that PPy-PLL was unable to improve either yield or enantioselectivity. New ligands are required to achieve the C-H activation and high enantioselectivity.

並列關鍵字

supramolecular assembly ； polypeptide ； activated urethane ； N-carboxyanhydride ； mercury nanoparticle ； Beckmann rearrangement ； C-H bond activation

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