We herein innovatively constructed the pure pH-dual channel probe DNOXA by the reaction of oxalyl chloride with 4-dimethylaminobenzaldehyde. DNOXA has two response sites for acidity, which are corresponding to pH-dual channel responses. When adding acid to pH 5.0, the protonation in the response site I enhanced the push-pull effect, and the absorption maxima of the optical spectra bathochromically shifted from 463 to 652 nm. When sequentially adding acid to pH 1.6, the response site II is awakened to work. The enhanced push-pull system was interrupted, and the absorption maxima hypochromatically shifted from 652 to 506 nm. In this process, the ratiometric change in the probe can be observed by naked-eye. Furthermore, quantum-chemical study well explained and supported the difference of their maxima absorption. Based on the excellent response of DNOXA to pH in vitro, DNOXA had commendable specific imaging and localization ability for lysosomes, undergoing dual channel images of protonation at the acidic microenvironment.

我们在此创新性地通过草酰氯与 4-二甲氨基苯甲醛反应构建了纯 pH 双通道探针DNOXA。DNOXA有两个酸度响应位点，对应于 pH 双通道响应。当添加酸至 pH 5.0 时，响应位点I 中的质子化增强了推挽效应，并且光谱的吸收最大值从 463 nm 向 652 nm 红移。当依次添加酸至 pH 1.6 时，响应位点II被唤醒工作。增强的推挽系统被中断，吸收最大值从 652 nm 移至 506 nm。在这个过程中，可以用肉眼观察探头的比例变化。此外，量子化学研究很好地解释并支持了它们的最大吸收差异。基于DNOXA对体外 pH 值的出色响应，DNOXA对溶酶体具有值得称赞的特异性成像和定位能力，在酸性微环境中进行质子化的双通道图像。