Triphenylamine pyridine acetonitrile fluorogens with green emission for pH sensing and application in cells

In this work, triphenylamine pyridine acetonitrile compounds PyA1, PyA2 and PyA3 are designed and synthesized. They show green fluorescence in water and bright emission in solid state. They have large Strokes shift (about 100 nm). The excitation and emission spectra are investigated in ethyl acetate, chloroform, cyclohexane, ethanol, water, acetonitrile, THF, DMF and DMSO. It is interesting to find that these compounds are able to sense increasing pH values ranging from pH 2 to 7 by showing different color and emission intensities: almost no emission at pH 2 and strong green emission at pH 7. The acid–base switched color and fluorescence changes can be observed under UV irradiation, in water solution and 1% agarose gel. These changes can be repeated for several cycles. We are able to employ these compounds for cell pH environment imaging.

We have designed three triphenylamine pyridine acetonitrile compounds PyA1, PyA2 and PyA3 as pH sensors, they show green fluorescence at pH 7 while no fluorescence at pH 2, these compounds also can be used for cell pH environment imaging.Figure optionsDownload as PowerPoint slide