Conversion from Heterometallic to Homometallic Metal-Organic Frameworks

Area of Science:

• Materials Chemistry
• Inorganic Chemistry
• Crystallography

Background:

• Metal-organic frameworks (MOFs) offer tunable structures for diverse applications.
• Lanthanide and zinc ions are key components in developing functional MOFs.

Purpose of the Study:

• Synthesize and characterize novel heterometallic and homometallic MOFs using a C3-symmetric ligand.
• Investigate the structural, thermal, and gas sorption properties of the synthesized MOFs.
• Explore the potential for framework metal-ion exchange between lanthanide ions.

Main Methods:

• Solvothermal synthesis of MOFs.
• Single-crystal X-ray diffraction (SXRD) for structural analysis.
• Thermogravimetric analysis (TGA) for thermal stability.
• Powder X-ray diffraction (PXRD) for structural integrity during drying.
• Gas sorption analysis.
• Photoluminescence (PL), IR, ICP-AES, and EDX for metal-ion exchange confirmation.

Main Results:

• Two heterometallic (LnZnTPO) and two homometallic (LnTPO) MOFs were successfully synthesized.
• SXRD confirmed isostructural relationships between heterometallic and homometallic pairs.
• TGA indicated high thermal stability up to 450°C.
• PXRD showed pore-structure stability during drying.
• Gas sorption isotherms were similar for isostructural MOFs.
• Framework metal-ion exchange was achieved, converting LnZnTPO to Ln'TPO.

Conclusions:

• The synthesized MOFs exhibit robust structures and thermal stability.
• The materials demonstrate potential for post-synthetic modification via metal-ion exchange.
• These findings contribute to the development of functional lanthanide-based MOFs.