Structural Effect on Proton Conduction in Two Highly Stable Disubstituted Ferrocenyl Carboxylate Frameworks

Area of Science:

• Materials Science
• Solid-State Chemistry
• Electrochemistry

Background:

• Developing solid crystalline materials with high proton conductivity is challenging.
• Understanding proton conduction mechanisms in these materials is crucial for applications.
• Ferrocene-based materials offer unique structural and electronic properties for exploration.

Purpose of the Study:

• To synthesize and characterize novel disubstituted ferrocenyl carboxylate frameworks (DFCFs).
• To investigate the water-assisted proton migration and conductivity of these DFCFs.
• To elucidate the role of carboxyl group arrangement in determining proton conduction properties.

Main Methods:

• Single crystal X-ray diffraction for structural characterization.
• Systematic investigation of water-assisted proton migration.
• Proton conductivity measurements under varying humidity and temperature conditions.

Main Results:

• Two DFCFs, DFCF 1 and DFCF 2, were successfully synthesized and structurally characterized.
• DFCF 1 exhibited ultrahigh proton conductivity (1.14 × 10⁻² S·cm⁻¹) at 373 K and 98% RH.
• DFCF 2 displayed significantly lower proton conductivity (1.99 × 10⁻⁵ S·cm⁻¹), attributed to carboxyl group arrangement.

Conclusions:

• The arrangement of free carboxyl groups, not just their density, critically influences proton conductivity in ferrocenyl frameworks.
• DFCF 1's high conductivity is linked to its specific carboxyl group arrangement.
• This study provides new insights for designing high proton conductive materials utilizing free carboxyl groups.