Multifunctional Chiral Three-Dimensional Phosphite Frameworks Showing Dielectric Anomaly and High Proton Conductivity

Area of Science:

• Coordination Chemistry
• Materials Science
• Solid-State Chemistry

Background:

• Chiral metal-organic frameworks (MOFs) are of interest for asymmetric catalysis and separation.
• Proton conductivity in MOFs is crucial for energy applications like fuel cells.

Purpose of the Study:

• To synthesize and characterize novel 3D chiral Cobalt(II) phosphite frameworks.
• To investigate the dielectric properties and proton conductivity of the synthesized materials.

Main Methods:

• Ionothermal synthesis of 3D Cobalt(II) phosphite frameworks.
• Single-crystal X-ray diffraction for structural analysis.
• Dielectric measurements and conductivity studies.

Main Results:

• The framework crystallizes in the chiral space group P3221, adopting a chiral 4-connected qtz net topology.
• A multistep dielectric response was observed, attributed to the reorientation of 1,4-dimethyl-1,4-diazabicyclo[2.2.2]octane (Me2-DABCO) within the chiral cavities.
• High proton conductivity (1.71 × 10^-3 S cm^-1) was achieved at room temperature, facilitated by dense hydrogen-bonding networks.

Conclusions:

• The synthesized chiral Cobalt(II) phosphite frameworks possess unique structural and functional properties.
• The materials demonstrate potential for applications in dielectric devices and proton conduction.