A Novel Ratiometric Fluorescent Mercury Probe Based on Deprotonation-ICT Mechanism
作者:Puhui Xie、Fengqi Guo、Sen Yang、Denghui Yao、Guoyu Yang、Lixia Xie
DOI:10.1007/s10895-013-1316-5
日期:2014.3
A new NBD-rhodamine dye (1) was developed as a colorimetric and ratiometric fluorescent chemosensor for Hg2+ with good selectivity in aqueous ethanol solutions under neutral to basic conditions. Sensor 1 showed absorption at 468 nm and a weak emission at 529 nm (ϕ F = 0.063) in ethanol/aqueous tris buffer (9:1, v/v) of pH 9.17 solution. Bathochromic shifts in both absorption (492 nm) and fluorescence spectra (569 nm, ϕ F = 0.129), respectively upon addition of 2 equiv. of Hg2+ were observed. The ring-opening reaction of the spirolactam form to the corresponding xanthene form was not found. The interaction of Hg2+ with chemosensor 1 resulted in the deprotonation of the secondary amine conjugated to the NBD component so that the electron-donating ability of the N atom was enhanced. Deprotonation-ICT mechanism of secondary amines was suggested for the ratiometric fluorescent chemosensing for Hg2+.
开发了一种新型 NBD-罗丹明染料 (1),作为 Hg2+ 的比色和比率荧光化学传感器,在中性至碱性条件下在乙醇水溶液中具有良好的选择性。传感器 1 在 pH 9.17 的乙醇/三羟甲基氨基甲烷缓冲液(9:1,v/v)溶液中显示出 468 nm 处的吸收和 529 nm 处的微弱发射 (ψ F = 0.063)。添加 2 当量后,吸收光谱 (492 nm) 和荧光光谱 (569 nm, ψ F = 0.129) 分别发生红移。观察到 Hg2+。没有发现螺内酰胺形式到相应的呫吨形式的开环反应。 Hg2+与化学传感器1的相互作用导致与NBD成分结合的仲胺去质子化,从而增强了N原子的供电子能力。建议将仲胺的去质子化-ICT 机制用于 Hg2+ 的比率荧光化学传感。