銅 (II) 離子及氟離子螢光感測分子之合成與應用

Abstract

本論文以 coumarin設計出感測分子 1，化合物 1 藉由顏色(黃色變成紅色) 及螢光的改變 (從綠色螢光變成沒有螢光) 來辨識 Cu2+ 離子，在其他金屬離子同時存在下，仍對 Cu2+ 離子有很好的選擇性。從氫譜滴定實驗得知，化合物 1 以 OH group 及 imine 上的 N 原子與 Cu2+ 離子形成錯合，因分子內的能量轉移，使螢光淬熄。由 Job plot 得知 1-Cu2+ 的錯合比例為 2:1。1-Cu2+ 之結合常數為 9.56 × 109 M-2。化合物 1 的最佳 pH 值範圍為 5.0-9.0。 以 salicylaldehyde 為基底設計出感測分子 FS1、FS2。化合物 FS1 藉由藍色螢光的 turn-on 來辨識 F- 離子，在其他陰離子同時存在下，對 F- 離子仍有高度的選擇性。當加入 F- 離子後，F- 離子會和化合物 FS1 進行化學反應，生成一有強烈綠色螢光的產物，其反應速率常數 0.0155 min-1。化合物 FS1 在鹼性條件下，可以更有效的辨識 F- 離子。 化合物 FS2 藉由藍色螢光的 turn-on 來辨別 F- 離子，在有其他陰離子的存在下，對 F- 離子仍有高度的選擇性。 在 F- 離子存在下，化合物 FS2 會和 F- 離子發生化學反應，生成一有藍色螢光的產物，其反應速率常數為 0.07757 min-1。

In this thesis, a chemosensor 1 based on coumarin had been designed and successfully synthesized for detecting Cu2+, and two chemosensors FS1 and FS2 were designed for F- detection. Chemosensor 1 indicated the presence of Cu2+ among other metal ions with high selectivity by color change from yellow to red and significant fluorescence quenching. According to 1H NMR studies, addition of Cu2+ caused the disappearance of hydroxyl (OH) hydrogen signal and broadening of imine hydrogen signal. These observations indicate that Cu2+ binding with chemosensor 1 is mainly through one oxygen atom and one nitrogen atom at imine. The binding ratio of 1–Cu2+ complexes was determined as 2 : 1 according to Job plot. According to Cu2+ titration, the association constant of 1-Cu2+ complex was decided as 9.56 × 109 M-2. The best pH range for detecting Cu2+ by 1 was from 5.0 to 9.0. Chemosensors FS1 and FS2 exhibit fluorescence enhancement in the presence of F- ions over competing anions Br-, CN-, Cl-, H2PO4-, I-, NO2-, NO3-, N3-, OAc- and P2O74-. Moreover, fluorescence microscopy experiments showed that FS1 can be used as a fluorescent probe for detecting F- ions in living cells. The best pH range for detecting F- by FS1 was from 7.0 to 10.0. The limit of detection of FS1 and FS2 were 1.45 μM and 0.274 μM, respectively.