A Highly Sensitive Fluorescent Probe for Selective Detection of Al³⁺ Cation by Switching the Solvent from Aprotic to Protic Environment

Abstract

We have designed and synthesized known coumarin-rhodamine (CR1) derivative for sensing the Al³⁺ ion in the presence of aprotic (CH₃CN/H₂O) medium via TBET mechanism. The results of the photo physical studies revealed that the sensing mechanism involves Al³⁺ induced change from non-fluoroscent (spirolactam form) to fluorescent (ring opening form) in CR1 leading to the visible color change. The Job's plot indicated the formation of 2:1 complex between CR1 and Al³⁺ with limit of detection is 1.78 × 10⁻⁸ M. Various spectroscopy techniques and theoretical calculation have been employed to investigate the mechanism of the sensing property of CR1 with Al³⁺.

Keywords:

• Rhodamine
• Coumarin
• TBET
• FRET
• Energy band gap

Acknowledgments

This study was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (Grant no. 2014006660).