香豆素衍生物單體及其寡聚合物在化學感測分子的研發

Applications of Oligomers having Pendant Coumarins in the Metal Ions Sensing

林喻偵(Yu-Chen Lin)

指導教授 ： 陳昭岑

國立臺灣大學/理學院/化學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.10168

摘要

在本實驗室先前的研究發現，螢光感測分子以香豆素 (coumarin)為訊號傳遞單元，結合具有金屬離子辨識單元─冠醚 (azacrown) 的香豆素衍生物1對重金屬離子具有高選擇性，且在有機溶劑中能呈現出非常高的螢光特性。有鑑於此，我們將探討香豆素7號位置二乙基胺基置換成具有雙鍵官能基的取代基—norbornene，利用金屬釕錯合物做為進行開環歧化聚合反應的催化劑 (Grubbs’ catalyst)，用以建構同聚合物 (homopolymer) 及共聚合物 (copolymer)。藉由偵測單體及聚合體光學性質的差異，研發化學感測器的可行性。 利用修飾norbornene的香豆素衍生物4作為單體與環辛烯所合成的一系列共聚合物 (22∼26)，其溶解度在二氯甲烷及三氯甲烷溶劑為可溶，在四氫呋喃微溶。在二氯甲烷溶液中以鍶離子滴定有明顯螢光增強現象，螢光變化強度為125倍。當置於極性較高的溶劑─四氫呋喃，以鐵離子滴定時可由肉眼觀察到顏色會由淡黃色轉為粉紅色。所以我們可以分別利用螢光及顏色變化達到金屬離子偵測的目的。 若以不飽和環氧基烯28取代環辛烯與香豆素衍生物進行開環歧化聚合反應，所生成寡聚合物29因為烷醚鏈加入，改善了聚合物溶解度。在二氯甲烷溶液中以金屬離子滴定，發現以鈉離子變化最為明顯，結果顯示烷醚鏈的加入不僅影響到聚合物溶解度，也會參與與金屬離子結合。

關鍵字

香豆素 ； 化學感測分子

並列摘要

In our previous research, we found that fluorosensor 1 with coumarin as the signal-transducing unit and with azacrown as the recognition unit provides high selectivity to heavy-metal ions and displays high fluorescence intensity in organic solvents. According to these experiment results, we replace diethylamine at 7-position of coumarin with norbornene, a functional group provide double bond for ROMP. Copolymerization by ring-opening metathesis may direct a new route to tune optical properties of sensors through combinations of various monomers and through stoichiometry of monomers.
We tune the ratio of coumarin-functionalized monomer 4 to cycloalkene to produce a series of copolymers (22~26). Copolymers bearing pendant coumarins and hydrophobic backbone are highly selective for strontium ion and display high fluorescence change, a 125-fold enhancement in dichloromethane. We can also utilize color change to achieve metal-ions detection by naked eyes. Thus we find color change from pale yellow to pink in tetrahydrofuran when iron ion is added.
We use unsaturated crown ether 28 instead of cycloalkene to produce copolymers bearing hydrophilic backbone. Copolymer 29 having hydrophilic backbone is highly selective for sodium ion and displays high fluorescence intensity in dichloromethane. Our experimental results indicate that incorporated hydrophilic backbone in our copolymers not only improves the solubility in acetonitrile but also participates in metal-ion binding.

並列關鍵字

Metal Ions Sensing ； Coumarin

參考文獻

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