A new fluorogenic probe for solution and intra-cellular sensing of trivalent cations in model human cells

•Newly synthesized colorimetric and flourogenic probe can selectively sense trivalent metal ions in mixed aqueous medium in ppm level.•Theoretical calculations justify the red shift and increase in emission intensity of L in the presence of M3+.•Interestingly, L alone and L in the presence of different trivalent cations were non-cytotoxic to model human cells (HeLa cells).•The switch ON emission behaviour of the ligand in the presence of M3+ is also demonstrated inside live HeLa cells.

A new imidazole functionalized anthracene based Schiff base (L) was synthesized and it's selective colorimetric as well as fluorescence responses to trivalent metal cations (Al3+, Fe3+ and Cr3+) over a variety of divalent and monovalent metal cations in 1:1 methanol–water mixed solvent and in live HeLa cells were demonstrated. These selective colorimetric and fluorescence responses were explained as a consequence of protonation of L, where the lower Ksp values of M3+ (Al3+, Fe3+ and Cr3+) facilitated the generation of H+ through hydrolysis. This fluorogenic behavior of the ligand L was further confirmed by theoretical calculations.

Graphical abstractA simple Schiff's base fluorogenic probe for trivalent cation is designed. The receptor is biocompatible and used for live cell imaging.Figure optionsDownload full-size imageDownload as PowerPoint slide