合成新型超分子主客系統分別以萘二甲醯亞胺/四苯基乙烯予體和玫瑰紅/螢光素受體探討其螢光共振能量轉移及金屬離子檢測之研究

Study of Supramolecular FRET Host-Guest Systems Containing Respective Naphthalimide/Tetraphenylethylene Donors and Rhodamine B/Fluorescein Acceptors and Their Applications for Metal Ion Detections

陳晧宇(Hao-Yu Chen)

指導教授 ： 林宏洲

國立交通大學/工學院/材料科學與工程系所/碩士(2020年)

摘要

在本篇論文中，我們成功將雙螢光發色團導入擬輪烷([3]pseudo-rotaxane)中，利用動態超分子系統本身特性探討其螢光共振能量轉移能力。第一部分中，以冠醚大環(dibenzo-24-crown-8 ether (DB24C8)) 與二級胺結構間特殊的主客交互作用得到刺激響應之擬輪烷(RH-Naph)，其中萘二甲醯亞胺修飾之環狀分子作為主體(Naph) 而玫瑰紅衍伸物是客體(RH)。RH-Naph 的光致發光行為受到FRET調控，缺乏能量轉移的情況下 RH-Naph散發綠光(530 nm);然而, FRET 誘導橘光(600 nm)產生則是因為開環之客體分子RH-O作為受體接收Naph的放射能量。基於RH-Naph內螺環在酸性環境催化及鐵離子(Fe3+)交互作用下應答開環，我們更可藉由兩特徵放光間比例關係(530 nm及600 nm) 瞭解RHNaph內能量轉移的過程。 為了更好解釋FRET效率與主客體之空間距離的關系，我們進一步調查對RH去質子化所得之主客混合物(R-Naph)及其FRET 表現，然而RH-Naph內超分子作用力能使主客體互相識別而縮短空間距離且具有最好的能量轉移效率。得力於RH-ONaph 優秀的能量轉移效率， RH-Naph可利用特徵放光間的相對變化作為 Fe3+ 感測材料且具有良好專一性以及低偵測極限(LOD = 39.01 nM);更甚的是，透過氰化物(cyanide, CN-)與金屬錯合物(RH-O+Fe3+)-Naph的配體競爭作用，Fe3+ 更易與CN- 配位而脫離，誘使(RH-O)-Naph合環反應而阻斷能量轉移過程且恢復萘二甲醯亞胺的綠色螢光，因此在超分子系統交互加入Fe3+/CN- 我們能可逆調控RH-Naph 的FRET過程。
論文的第二部分，我們合成以四苯基乙烯修飾之冠醚環為主幹之主鏈聚合物(poly(Cy-TPE))且能與一螢光素衍伸之軸分子(FlH)自組裝形成新型擬輪烷 (FlH-poly(Cy-TPE))。四苯基乙烯單元賦予此poly(Cy-TPE) 聚集誘導發光現象 (Aggregation-Induced Emission, AIE) ，但有別於一般四苯基乙烯衍伸物，poly(Cy-TPE) 在極低水含量溶液便能展現 AIE 性質且具有穩定的藍色螢光。FlH-poly(Cy-TPE) 的光致發光行為受到FRET調控，缺乏FRET支持的情況下FlH-poly(Cy-TPE) 散發藍光(470 nm);然而, FRET 過程誘使黃綠光(525 nm)產生則是來自FlH-O作為受體接收四苯基乙烯的放射能量。FlH-poly(Cy-TPE)內螺環對鹼性環境因素及鋁離子(Al3+)交互作用下應答開環，從而進行FRET 過程;除此之外，我們更可藉由特徵放光的比例關係(470 nm 及 525 nm) 觀測FlH-poly(Cy-TPE)內能量轉移的過程。為了更好說明聚合物誘導AIE效應對FRET 過程的影響及主客體空間距離對應之FRET效率;對FlH去質子化所得之主客混合物 (Fl-poly(Cy-TPE)及Fl-(Cy-TPE)) 更進一步用於解釋 FRET 行為，從而確認 FlH-poly(Cy-TPE)具有最好的能量轉移效率。基於(FlH-O)-poly(Cy-TPE) 優秀的能量轉移效率， 更因為FRET過程間特徵放光的變化FlH-poly(Cy-TPE)能作為Al3+ 感測材料且具有專一性以及卓越的偵測極限(LOD = 38.59 nM);更甚的是，透過焦磷酸鹽(pyrophosphate, PPi4+) 配體與金屬錯合物(FlH-O+Al3+)-poly(Cy-TPE) 之相互競爭作用，Al3+ 更傾向與PPi4+ 形成Al4(PPi)3 從而從錯合物中脫離，迫使(FlH-O)-poly(Cy-TPE)合環反應且打斷FRET 同時恢復四苯基乙烯之藍色螢光，因此我們能以配體競爭作用可逆調控FlH-poly(Cy-TPE) 的光致放光表現。更另我們驚喜的是FlH-poly(Cy-TPE) 能在鈀金屬(Pd2+) 與超分子作用力的協同作用下形成網狀聚合物，更而在快速加熱/冷卻的過程下得到有機凝膠(FlH+Pd2+)-poly(Cy-TPE)。刺激響應之有機凝膠被證實能在膠體與溶液態之間的可逆轉換，同時展現出不錯的機械性質，使此類智慧材料不僅可用於化學感測器，更有潛力作為新型軟性材料。

關鍵字

超分子主客系統 ； 聚集誘導發光 ； 螢光共振能量轉移 ； 金屬離子檢測

並列摘要

In this dissertation, we focus on the bifluorophoric combination of Förster resonance energy transfer (FRET) process between a pair of energy donor-acceptor fluorophores within one pseudo-rotaxane architecture. In the first, we have designed and synthesized a multi-stimuli responsive switchable [3]pseudo-rotaxane (RH-Naph), which consists of bis-naphthalimide-functionalized crown ether as a host (Naph) and rhodamine-mortified axle as a guest (RH). This host-guest system exhibits green emission of naphthalimide at 530 nm without FRET, whereas strong FRET phenomenon with orange emission would be observed in (RH-O)-Naph due to the energy transfer from Naph donor to ring-opened rhodamine acceptor (RH-O) in semi-aqueous solutions. In addition, distinct FRET process of RH-Naph can be observed under acid-based conditions and ferric ion (Fe3+) interactions through the specific ratiometric fluorescence change at 530 and 600 nm. To better understand the FRET efficiency of our [3]pseudo-rotaxane, we also investigated FRET behaviors of RH-Naph and physical mixture R-Naph (deprotonation of RH) to confirm the best energy transfer in [3]pseudo-rotaxane rather than in mixture. Importantly, based on highly efficiency FRET of (RH-O)-Naph, RH-Naph could be utilized for Fe3+ detection with significant limit of detection (LOD = 39.01 nM) via ratiometric fluorescences between RH-O orange emission (600 nm) and Naph green emission (530 nm). Moreover, the reversible fluorescence of RH-Naph could be controlled by cyanide (CN-) adding into (RH-O+Fe3+)-Naph to recover green emission of naphthalimide and shut down the FRET process.
In the second, we have fabricated a novel aggregation-induced emission (AIE) main-chain polymer (poly(Cy-TPE)), containing tetraphenylethylene (TPE)-based macrocyclic dibenzo-24-crown-8 ether (DB24C8), exhibiting a unique feature of TPE aggregation due to amplification of polymer aggregation that the AIE emission could sustain in extremely low water contents solutions. The poly(Cy-TPE) as a host could self-assemble with the fluorescein-mortified axle unit (FlH) to generate poly(pseudo-rotaxane) (FlH-poly(Cy-TPE)). This host-guest system exhibits blue emission of TPE at 470 nm without FRET; however, strong FRET phenomenon with green emission at 525 nm would be observed in (FlH-O)-poly(Cy-TPE) due to the energy transfer from poly(Cy-TPE) donor to ring-opened fluorescein acceptor (FlH-O) in semi-aqueous solutions. Moreover, the exquisite perturbations of the medium factors, including pH values and aluminum ion, can be monitored in semi-aqueous system by distinct ratiometric fluorescence change at 470 and 525 nm of FRET behaviors. To better understand the FRET efficiency of this poly(pseudo-rotaxane), we also investigated FRET behaviors of FlH-poly(Cy-TPE) and FlH-(Cy-TPE) with their physical mixtures Fl-poly(Cy-TPE) and Fl-(Cy-TPE) (deprotonation of FlH) to confirm the best energy transfer in poly-(pseudo-rotaxane) rather than in other states. In addition, based on highly efficiency FRET of (FlH-O)-poly(Cy-TPE), FlH-poly(Cy-TPE) could be utilized for Al3+ detection with significant limit of detection (LOD = 38.59 nM) via ratiometric fluorescences between FlH-O green emission (525 nm) and TPE blue emission (470 nm). Furthermore, the reversible fluorescence of FlH-poly(Cy-TPE) could be controlled by pyrophosate (PPi4-) adding into (FlH-O+Al3+)-poly(Cy-TPE) to recover blue emission of tetraphenylethylene and turn off the FRET process. Interestingly, the poly(pseudo-rotaxane) can generate supramolecular polymeric network gel with palladium (II) co-ordination in DMF/DCM (2:1, v/v). By virtue of orthogonal non-covalent interactions through host-guest recognition and metal-ligand co-ordination, the organogel ((FlH+Pd2+)-poly(Cy-TPE)) can undergo a reversible sol-gel transition in regards to distinct stimuli (thermo-induced and competitive ligand of PPh3) and exhibit good mechanical property.

並列關鍵字

Supramolecular Host-Guest system ； AIE ； FRET ； Metal ion detections

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