A novel colorimetric and turn-on fluorescent chemosensor for iron(III) ion detection and its application to cellular imaging

•A novel bis-(rhodamine) based probe Rh-2 for detection of Fe3 + was synthesized•The probe exhibited highly selective and sensitive colorimetric and “turn on” fluorescence enhancement towards Fe3 + ions•It could be served as a naked-eye and fluorescence indicator for Fe3 + ions.•The probe has been used for imaging intracellular Fe3 + ions successfully.

A novel rhodamine-based dual probe Rh-2 for trivalent ferric ions (Fe3 +) was successfully designed and synthesized, which exhibited a highly sensitive and selective recognition towards Fe3 + with an enhanced fluorescence emission in methanol-water media (v/v = 7/3, pH = 7.2). The probe Rh-2 could be applied to the determination of Fe3 + with a linear range covering from 3.0 × 10− 7 to 1.4 × 10− 5 M and a detection limit of 1.24 × 10− 8 M. Meanwhile, the binding ratio of Rh-2 and Fe3 + was found to be 1:1. Most importantly, the fluorescence and color signal changes of the Rh-2 solution were specific to Fe3 + over other commonly coexistent metal ions. Moreover, the probe Rh-2 has been used to image Fe3 + in living cells with satisfying results.

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