A novel rhodamine-based fluorescent and colorimetric “off–on” chemosensor and investigation of the recognizing behavior towards Fe3+

A novel rhodamine based probe has been synthesized as an “off–on” chemosensor for Fe3+. Upon coordination with Fe3+, the probe displayed good brightness and fluorescent enhancement. A linear relationship was observed to exist between the relative fluorescence intensity of this probe and the concentration of Fe3+ in the range of 5 μM–20 μM with a detection limit of 5 μM. It offered highly sensitive toward Fe3+ over other ions. The recognizing behaviors toward Fe3+ have been investigated both experimentally and computationally. It can be expected that Fe3+ coordinated with the N atom of thiazole moiety in the probe accompanied by the transferring of electrons of the phenylthiazole resulted in the opening of the spiro-ring.

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► A novel rhodamine derived fluorescent probe has been synthesized.
► The probe shows an intense fluorescent intensity and a clear color change.
► It offers highly sensitive toward Fe3+ over other cations.
► Its recognizing behavior towards Fe3+ has been investigated.