Selective Turn-on Fluorescent Chemosensors for Zn2+

• Main Authors: Liu, Hao-Ming, 劉浩敏
• Other Authors: 吳淑褓
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/83548961019625517788

碩士 === 國立交通大學 === 應用化學系碩博士班 === 100 === 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+.