f-block MOFs: A Pathway to Heterometallic Transuranics

Area of Science:

• Materials Science
• Nuclear Chemistry
• Radiochemistry

Background:

• Metal-organic frameworks (MOFs) offer tunable properties for diverse applications.
• Actinide-based materials are crucial for nuclear energy and medicine, but their synthesis and characterization are challenging.

Purpose of the Study:

• To synthesize and characterize novel heterometallic actinide-MOFs, including transuranic elements like uranium (U) and plutonium (Pu).
• To investigate the kinetics and thermodynamics of heterometallic actinide-MOF formation.
• To explore the fundamental properties of these novel materials for potential applications.

Main Methods:

• Synthesis of heterometallic f-block-frameworks, including transuranic uranium/plutonium-MOFs and a plutonium-analog.
• Theoretical calculations to probe formation kinetics and thermodynamics.
• Characterization of electronic structure (density of states), thermodynamic properties (enthalpy of formation), band gap, proton affinity, and stability.

Main Results:

• Reported the first transuranic heterometallic uranium/plutonium-MOFs and a monometallic plutonium-MOF.
• Determined the first U-to-Th transmetallation rate, identifying uranyl species formation as a driving force for metathesis.
• Achieved 97% of theoretical maximum capacity for actinide integration.
• Characterized key material properties as a function of metal ratios.

Conclusions:

• Formation of uranyl species is a key factor in solid-state metathesis for actinide-MOF synthesis.
• These novel actinide-MOFs exhibit tunable properties and high integration capacity.
• The findings advance fundamental understanding of actinide chemistry and enable development of new actinide-containing materials for applications like radioisotope thermoelectric generators and metalloradiopharmaceuticals.