以dipyrrin為基底設計之新型鋅(II)離子螢光感測分子之合成與應用

Abstract

本論文分別以dipyrrin為基底，設計合成出螢光化學感測分子DP1、DP2、DP3。此系列感測分子皆是藉由黃色螢光turn-on的方式來辨識Zn(II)，在其他金屬離子的存在下，仍對Zn(II)具有選擇性。由核磁共振氫譜得知，DP1以dipyrrin的氮原子和benzoimidazole上的亞胺基與Zn(II) 鍵結。由Job plot和MS(ESI)可得知DP1 – Zn(II) 的錯合比例為1 : 1。由Benesi-Hildebrand plot 得知DP1 – Zn(II)之結合常數為6.12*104 M-1，對於鋅離子濃度的偵測極限為0.236 μM，錯合Zn(II)後量子效率由0.005提昇至0.10。 DP2則是將DP1的芳香環部份由芘改成苯，同樣具有辨識Zn(II)的能力，以1:1方式錯合，偵測極限是0.325 μM，結合常數為6.64*104 M-1，量子效率是0.017。DP3是將DP2結構的benzoimidazole部份改成benzothiazole，以1:1方式與Zn(II)錯合，結合常數為1.47*105 M-1，偵測極限為0.492，量子效率為0.026。

In this thesis, three chemosensors DP1, DP2 and DP3 based on dipyrrins were designed for Zn2+ detection. DP1 produced significant fluorescence enhancement (20 fold) in the presence of Zn2+ ion, while the metal ions Ag+, Ca2+, Cd2+, Co2+,Cu2+, Fe2+,Fe3+, Hg2+, Mg2+, Mn2+, Ni2+ and Pb2+ produced only minor changes in fluorescence. After addition of more than one equivalent of Zn2+, the emission intensity reached a maximum, at which the quantum yield was 0.10. According to 1H NMR studies, addition of Zn2+ caused the disappearance of amine (NH) hydrogen signal. This observation indicates that Zn2+ binding with DP1 is mainly through one nitrogen atom at benzoimidazole moiety and two nitrogen atoms at the dipyrrin group. The binding ratio of DP1–Zn2+ complexes was determined as 1 : 1 according to Job plot. Using Benesi-Hildebrand plot, the binding constant of DP1–Zn2+ complexes was decided as 6.12 x 104 M-1. The detection limit of the DP1-Zn2+ was 0.236 μM. The quantum yield and the binding constant of the DP2-Zn2+ were 0.017 and 6.64*104 M-1, respectively. The detection limit was 0.325 μM of DP2 for binding Zn2+. The quantum yield and the binding constant of DP3–Zn2+ complexes were 0.026 and 1.47*105 M-1, respectively. The detection limit was 0.492 μM of DP3 for detecting Zn2+.