A water-soluble Fe3+ selective fluorescent turn-on chemosensor: Preparation, theoretical study and its optical vitro imaging

A rhodamine derivative bearing a thiazole receptor (probe 1) was developed and characterized. Probe 1 rendered a prominently chromogenic and turn-on fluorescent signal toward Fe3+ ion in aqueous media based on coordination reaction. Probe 1 also showed high sensitivity toward Fe3+ ion with the detection limit as low as 92 nM. By means of the Job's plot, 2: 1 binding mode of 1-Fe3+ complex was determined and a possible sensing mechanism was further proposed based on the changes in the Fourier Transform Infrared (FT-IR) and mass spectra. The turn-on fluorescence and sensing mechanism for 1-Fe3+ complex were well demonstrated by theoretical calculations. Importantly, probe 1 has been tested highly suitable for mapping Fe3+ ion in human colon cancer cells SW480, providing a wonderful candidate for tracking Fe3+ in biological processes.