Fluorescence-Responsive Detection of Ag(I), Al(III), and Cr(III) Ions Using Cd(II) Based Pillared-Layer Frameworks

Area of Science:

• Materials Science
• Inorganic Chemistry
• Crystallography

Background:

• Coordination polymers (CPs) are advanced materials with tunable structures and properties.
• Developing CPs with enhanced stability and sensing capabilities is crucial for various applications.

Purpose of the Study:

• To synthesize and characterize two new Cd(II)-based coordination polymers.
• To investigate their structural, thermal, and luminescent properties.
• To evaluate their potential as sensors for specific metal ions.

Main Methods:

• Hydro(solvo)thermal synthesis of Cd(II) coordination polymers.
• Single-crystal X-ray diffraction for structural determination.
• Thermogravimetric analysis (TGA) for thermal stability assessment.
• Luminescence spectroscopy for optical property analysis.
• Metal ion sensing experiments in aqueous suspension.

Main Results:

• Two Cd(II) CPs, {Cd3(btc)2(BTD-bpy)2]∙1.5MeOH∙4H2O}n (1) and [Cd2(1,4-ndc)2(BTD-bpy)2]n (2), were successfully synthesized.
• Compound 1 features a 3D non-interpenetrating pillared-bilayer framework, while Compound 2 exhibits a 3D interpenetrating bipillared-layer framework.
• Both compounds demonstrated excellent water and thermal stability (up to 350 °C).
• Compounds 1 and 2 emitted blue fluorescence in solid and aqueous states.
• Selective sensing of Ag+, Al3+, and Cr3+ was achieved through fluorescence quenching and enhancement mechanisms.

Conclusions:

• The synthesized Cd(II) coordination polymers possess robust structural and thermal stability.
• Their luminescent properties enable sensitive and selective detection of specific metal ions in aqueous solutions.
• These materials show promise for applications in chemical sensing and materials science.