Anthracene-Based Highly Selective and Sensitive Fluorescent "Turn-on" Chemodosimeter for Hg²

Area of Science:

• Analytical Chemistry
• Materials Science
• Organic Chemistry

Background:

• Mercury ions (Hg2+) pose significant environmental and health risks due to their toxicity.
• Developing sensitive and selective detection methods for Hg2+ is crucial for monitoring and remediation.
• Fluorescent chemosensors offer advantages in sensitivity, selectivity, and real-time detection capabilities.

Purpose of the Study:

• To synthesize novel anthracene-bearing thioacetals as fluorescent chemosensors for Hg2+ detection.
• To investigate the fluorescence "turn-on" sensing mechanism based on hydrolysis and desulfurization.
• To evaluate the chemosensors' efficacy in detecting Hg2+ in the presence of other metal ions and in live cell imaging.

Main Methods:

• Synthesis of three π-extended anthracene-bearing thioacetals (compounds 1-3).
• Spectroscopic studies (fluorescence spectroscopy) to analyze the response to Hg2+ ions.
• Quantum yield measurements and correlation with molecular structure.
• Competitive metal ion studies and limit of detection analysis.
• Fluorescence microscopic imaging in live cells.

Main Results:

• Compounds 1-3 exhibit a fluorescence "turn-on" response to Hg2+ via a desulfurization-hydrolysis mechanism.
• The formation of highly fluorescent aldehyde products was observed, with increased quantum yields.
• The chemosensors demonstrated high selectivity for Hg2+ over other tested metal ions.
• Achieved nanomolar detection limits for Hg2+ (94 nM for 1, 59 nM for 2, 235 nM for 3).
• Compounds 1 and 2 were successfully used for fluorescence imaging in live cells.

Conclusions:

• The synthesized thioacetals are effective fluorescent chemosensors for Hg2+ detection.
• The desulfurization-hydrolysis mechanism provides a reliable basis for the "turn-on" fluorescence response.
• These compounds show promise for detecting Hg2+ in complex environmental and biological matrices.
• Compounds 1-3 are potential candidates for practical applications in mercury monitoring and bioimaging.