Topological Control of Dual Protonic-Electronic Conduction in Metal-Organic Frameworks

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) are crucial for energy conversion and chemical separation due to their tunable properties.
• Achieving intrinsic dual proton-electron conductivity in a single MOF phase is a significant challenge.

Purpose of the Study:

• To design and synthesize novel Mn(II)-based conjugated MOFs with distinct topologies.
• To investigate the impact of framework topology on dual proton-electron conductivity.

Main Methods:

• Synthesis of two Mn(II)-based conjugated MOFs with kagome (kgm) and pseudo-bex-d topologies.
• Characterization of electronic and proton conductivity under varying humidity.
• Crystallographic and computational studies to elucidate conduction mechanisms.

Main Results:

• The Mn-HHTP-kgm MOF showed high electronic conductivity (8.4 × 10⁻¹ S cm⁻¹) but limited proton conductivity.
• The Mn-HHTP-bex-d MOF exhibited balanced electronic (2.4 × 10⁻⁵ S cm⁻¹) and proton conductivity (4.5 × 10⁻⁵ S cm⁻¹ at 98% RH).
• π-π stacking in kgm topology facilitated electron transport, while hydrogen-bonding networks in bex-d topology enabled proton transport.

Conclusions:

• Topological control is critical for modulating mixed-conduction properties in MOFs.
• These findings provide a pathway for designing multifunctional MOFs for applications in ambipolar devices, bioelectronics, and energy systems.