Multifunctional Two-Dimensional Metal-Organic Frameworks for Radionuclide Sequestration and Detection

Area of Science:

• Materials Science
• Inorganic Chemistry
• Coordination Chemistry

Background:

• Porous coordination polymers (PCPs) offer tunable structures for various applications.
• Lanthanide-based materials are explored for their unique optical and magnetic properties.

Purpose of the Study:

• Synthesize and characterize novel lanthanide-containing PCPs.
• Investigate the structural, thermal, and optical properties of these materials.
• Evaluate their potential for uranyl ion capture and X-ray scintillation.

Main Methods:

• Hydrothermal synthesis of lanthanide coordination polymers.
• Structural characterization using powder and single-crystal X-ray diffraction.
• Analysis of optical properties via absorbance, fluorescence, and lifetime spectroscopies.
• Assessment of uranyl ion adsorption and X-ray induced luminescence.

Main Results:

• Two new PCPs, [Ln₂(bpdc)₆(phen)₂]·nH₂O (1) and [Ln₂(bpdc)₆(terpy)₂]·3H₂O (2), were synthesized and characterized.
• Compound 1 exhibits a 2D framework, while compound 2 forms a 3D framework.
• Materials are stable in aqueous media (pH 3-10) and thermally stable up to ~400 °C.
• Ligand removal in compound 1 enhances surface area and pore volume.
• Eu³⁺-containing compound 1 effectively captures uranyl ions and exhibits luminescence.
• Both compounds with Eu³⁺ show red emission under X-ray irradiation, indicating scintillation potential.

Conclusions:

• The synthesized lanthanide-containing PCPs possess robust structures and tunable properties.
• Compound 1 demonstrates promise for selective uranyl ion detection and removal.
• These materials are viable candidates for solid-state scintillation detectors.