Structural Evolution from Noninterpenetrated to Interpenetrated Thorium-Organic Frameworks Exhibiting High Propyne...

Area of Science:

• Materials Science
• Inorganic Chemistry
• Crystallography

Background:

• Thorium-organic frameworks (TOFs) are advanced materials with potential applications in gas storage.
• Understanding the structural evolution of TOFs is crucial for designing materials with tailored properties.
• The 3,3',5,5'-tetrakis(fluoro)biphenyl-4,4'-dicarboxylate (TFBPDC) ligand offers unique possibilities for constructing complex frameworks.

Purpose of the Study:

• To synthesize and characterize two novel thorium-organic frameworks, Th-TFBPDC and Th-TFBPDC-i.
• To investigate the structural evolution from a noninterpenetrated to a 2-fold interpenetrated network.
• To evaluate the propyne (C3H4) storage capacity of the synthesized frameworks.

Main Methods:

• Hydrothermal synthesis of thorium-organic frameworks using the TFBPDC ligand.
• Single-crystal X-ray diffraction for structural determination.
• Computational studies to assess framework-guest interactions and pore volume.
• Propyne gas sorption measurements at ambient conditions.

Main Results:

• Two distinct thorium-organic frameworks, Th-TFBPDC and Th-TFBPDC-i, were successfully synthesized.
• A structural evolution from a 3D noninterpenetrated network (Th-TFBPDC) to a 2-fold interpenetrated network (Th-TFBPDC-i) was observed via a dissolution-recrystallization process.
• Th-TFBPDC exhibited high water stability and demonstrated excellent propyne storage capacity (8.16 mmol g⁻¹ at 298 K).

Conclusions:

• The study presents a rare example of structural transformation in thorium-organic frameworks.
• The ligand substitution mechanism driving the structural evolution was elucidated.
• Th-TFBPDC is identified as a highly promising metal-organic framework for efficient propyne storage applications.