A novel fluorescence probe based on triphenylamine Schiff base for bioimaging and responding to pH and Fe3 +

- The fluorescence probe is sensitive to pH in strong acid conditions.
- The fluorescence chemosensor can detect pH and Fe3 + simultaneously.
- The recognition is able to carry out in aqueous solution.
- The probe can also be applied for detecting Fe3 + in living cell and bioimaging.
- The sensor is synthesized easily with one step.

A novel fluorescence probe 1 based on triphenylamine was synthesized and characterized by NMR, IR, high resolution mass spectrometry and elemental analysis. Its fluorescence was quenched when pH below 2. There was a linear relationship between the fluorescence intensity and pH value ranged from 2 to 7. And its fluorescence emission was reversibility in acidic and alkaline solution. Furthermore, it exhibited remarkable selectivity and high sensitivity to Fe3 + and was able to detect Fe3 + in aqueous solution with low detection limit of 0.511 μM. Job plot showed that the binding stoichiometry of 1 with Fe3 + was 1:1. Further observations of 1H NMR titration suggested that coordination interaction between Fe3 + and nitrogen atom on C N bond promoted the intramolecular charge transfer (ICT) or energy transfer process causing fluorescence quenching. Additionally, 1 was also able to be applied for detecting Fe3 + in living cell and bioimaging.

Triphenylamine based fluorescence probe can detect pH and Fe3 + simultaneously in aqueous solution and be applied for detecting Fe3 + in living cell and bioimaging.135