Highly selective and anions controlled fluorescent sensor for Hg(2+) in aqueous environment

Area of Science:

• Analytical Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Mercury (Hg2+) is a toxic heavy metal pollutant with significant environmental and health implications.
• Development of highly selective and sensitive sensors for Hg2+ detection is crucial for monitoring and remediation.
• Existing sensors often face limitations in pH stability and selectivity.

Purpose of the Study:

• To synthesize and characterize a novel PET fluorescent sensor (B1) for selective Hg2+ detection.
• To evaluate the sensor's performance, including sensitivity, selectivity, and pH tolerance.
• To explore the sensor's potential applications in biological and toxicological contexts.

Main Methods:

• Synthesis and characterization of the BODIPY-based fluorescent sensor B1 with a penta-chelating receptor.
• Spectroscopic analysis (absorption and emission) to determine sensor properties.
• Fluorescence titration experiments to assess Hg2+ binding and quantum yield changes.
• pH-dependent studies to evaluate sensor performance across a wide pH range.

Main Results:

• The sensor B1 exhibits absorption at 498 nm and emission at 512 nm in the visible spectrum.
• Significant increase in fluorescence quantum yield from 0.008 (B1) to 0.58 (BHg1) upon Hg2+ binding.
• The sensor demonstrates a low pKa of 1.97, enabling Hg2+ detection over a broad pH range.
• The sensor showed cross-reactivity with certain anions (Cl-, Br-, CO32-, SCN-, CH3COO-) due to their coordination with Hg2+.

Conclusions:

• The developed PET fluorescent sensor B1 offers high selectivity and sensitivity for Hg2+ detection.
• Its wide pH operational range and low pKa make it suitable for diverse environmental and biological sample analyses.
• The sensor's response to specific anions warrants further investigation for potential multi-analyte sensing capabilities.