A new Cu²⁺-selective probe was developed based on the Cu²⁺-induced sequential hydrolysis and oxidative coupling reactions of 4-aminoantipyrine-appended 8-hydroxyquinoline derivative 1. Cu²⁺-assisted hydrolysis of the enamine moiety of Schiff base 1 afforded its constituents, 4-aminoantipyrine and 8-hydroxyquinoline-2-carboxaldehyde. The Cu²⁺-induced oxidative coupling between these in situ generated compounds afforded a quinoneimine dye. Prominent naked-eye-detectable selective signaling of Cu²⁺ ions, assisted by EDTA, was realized through a color change from faint yellow to pink with a detection limit of 1.81×10⁻⁶ M.

中文翻译：

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通过席夫碱的顺序水解和氧化偶联进行Cu2 +-选择性比色信号传递

基于Cu ²⁺诱导的4-氨基安替比林附加的8-羟基喹啉衍生物1的顺序水解和氧化偶联反应，开发了一种新的Cu 2 ^+-选择性探针。Cu2 ⁺辅助水解席夫碱1的烯胺部分提供了其成分4-氨基安替比林和8-羟基喹啉-2-甲醛。这些原位产生的化合物之间的Cu ²⁺诱导的氧化偶联提供了醌亚胺染料。通过从淡黄色到粉红色的颜色变化（检测极限为1.81×10 ^-6 M），在EDTA的辅助下，实现了Cu ²⁺离子的突出的肉眼可检测的选择性信号传导。