Fluorescence Enhanced Water-Soluble Ruthenium Complex: Advancing Precision in Cr(VI) Detection and Quantification

Area of Science:

• Analytical Chemistry
• Environmental Science
• Materials Science

Background:

• Hexavalent chromium (Cr(VI)) poses significant environmental and health risks due to its high toxicity and carcinogenicity.
• Accurate and rapid detection of Cr(VI) is crucial for public safety, regulatory compliance, and environmental monitoring.
• Existing detection methods may lack the sensitivity, selectivity, or speed required for comprehensive Cr(VI) analysis.

Purpose of the Study:

• To design and develop a novel fluorescence detector for sensitive and selective quantification of chromium (VI) ions.
• To synthesize and characterize a novel ruthenium(II) complex for use as a fluorescent probe.
• To evaluate the performance of the developed detector for Cr(VI) detection in aqueous solutions.

Main Methods:

• Synthesis of a novel ruthenium(II) complex: [Ru(bpy)₂(PhDORi)]Cl₂, where bpy is 2,2'-bipyridine and PhDORi is (2S,3R)-4-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)-butane-1,2,3-triol.
• Characterization of the synthesized complex using analytical and spectroscopic techniques, including UV-Vis absorption and cyclic voltammetry.
• Investigation of the complex's fluorescence properties and its response to chromate/dichromate anions in aqueous solution.

Main Results:

• The synthesized ruthenium(II) complex exhibited a metal-to-ligand charge transfer (MLCT) band at approximately 457 nm in aqueous solution.
• Cyclic voltammetry confirmed reversible one-electron oxidation and reduction processes involving the Ru(II)/Ru(III) couple.
• The complex displayed intense fluorescence upon excitation at the MLCT band and showed selective emission quenching in the presence of chromate/dichromate ions across a wide concentration range (ppm to ppb).

Conclusions:

• The novel ruthenium(II) complex serves as an effective fluorophore for the sensitive and selective detection of chromium (VI).
• The developed fluorescence detector demonstrates a broad linear response and high sensitivity for chromate ion quantification.
• This work provides a promising tool for the accurate monitoring of toxic chromium (VI) in environmental and public health applications.