A rhodamine-based off-on fluorescent chemosensor for selectively sensing Cu(II) in aqueous solution

Area of Science:

• Analytical Chemistry
• Materials Science
• Organic Chemistry

Background:

• Development of sensitive and selective chemosensors is crucial for detecting metal ions.
• Rhodamine-based fluorophores offer excellent optical properties for sensing applications.
• Salicylaldehyde derivatives are effective receptor units for metal ion binding.

Purpose of the Study:

• To synthesize and characterize a novel rhodamine-based chemosensor, RhB-pMOSal.
• To investigate the sensing capabilities of RhB-pMOSal for various metal ions.
• To evaluate the sensitivity and selectivity of RhB-pMOSal for Cu2+ detection.

Main Methods:

• Synthesis and full characterization of the RhB-pMOSal chemosensor.
• Absorption and fluorescence spectroscopy for metal ion sensing studies.
• Investigation of sensing behavior in neutral aqueous acetonitrile solution.

Main Results:

• RhB-pMOSal demonstrated a reversible and sensitive "turn-on" absorption and fluorescence response to Cu2+.
• A 65-fold enhancement in absorbance and a 6-fold enhancement in fluorescence intensity were observed upon Cu2+ addition.
• The sensor exhibited higher sensitivity to Cu2+ compared to a previously reported analogue, RhB-Sal.
• Minimal interference was observed from other common metal ions, except for slight fluorescence quenching by Cr3+.

Conclusions:

• RhB-pMOSal is a highly effective chemosensor for sensitive and selective detection of Cu2+.
• The novel sensor design offers improved performance over existing analogues.
• This chemosensor holds potential for practical applications in environmental monitoring and biological analysis.