A highly selective and sensitive turn-on fluorescent chemosensor based on rhodamine 6G for iron(III)

Abstract

Recently, more and more rhodamine derivatives have been used as fluorophores to construct sensors due to their excellent spectroscopic properties. A rhodamine-based fluorescent and colorimetric Fe3+ chemosensor 3',6'-bis(ethylamino)-2-acetoxyl-2',7'-dimethyl-spiro[1H-isoindole-1,9'-[9H]xanthen]-3(2H)-one (RAE) was designed and synthesized. Upon the addition of Fe3+, the dramatic enhancement of both fluorescence and absorbance intensity, as well as the color change of the solution, could be observed. The detection limit of RAE for Fe3+ was around 7.98 ppb. Common coexistent metal ions showed little or no interference in the detection of Fe3+. Moreover, the addition of CN- could quench the fluorescence of the acetonitrile solution of RAE and Fe3+, indicating the regeneration of the chemosensor RAE. The robust nature of the sensor was shown by the detection of Fe3+ even after repeated rounds of quenching. As iron is a ubiquitous metal in cells and plays vital roles in many biological processes, this chemosensor could be developed to have applications in biological studies. Iron you glad to see me: Herein, we report an easily synthesized turn-on fluorescent Fe3+ chemosensor based on rhodamine. The sensor displays highly selective and sensitive Fe3+-amplified fluorescence emission in acetonitrile even in the presence of other commonly interfering metal ions. Such fluorescent sensors for Fe3+ attract much attention due to the importance of Fe3+ in biological processes.