Asymmetrical Substitution Manipulates Stacking Modes in 2D Conductive MOF Crystals.

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Stacking modes in 2D conductive metal-organic frameworks (2D c-MOFs) are critical for controlling charge transport and carrier mobility.
• Achieving precise control over 2D c-MOF stacking via bottom-up synthesis is challenging due to dominant coordination bonds over weak van der Waals interactions.
• Most 2D c-MOFs are produced as nanocrystalline powders, hindering detailed structural analysis.

Purpose of the Study:

• To develop a novel strategy for controllable stacking and enhanced crystallinity in 2D c-MOFs.
• To investigate the impact of ligand modification on MOF structure and electrical properties.
• To establish fundamental structure-property correlations for rational design of 2D c-MOFs.

Main Methods:

• Modulating ligand electrostatic potential through asymmetrical fluorine atom substitution in hexahydroxytriphenylene (HHTP) ligands.
• Synthesizing two HHTP derivatives with distinct packing modes.
• Characterizing the resulting 2D c-MOF crystals for stacking configurations and electrical properties.

Main Results:

• Successful synthesis of 2D c-MOF crystals with distinct, controllable stacking modes.
• Demonstrated tunable electrical properties correlated with ligand stacking configurations.
• Achieved enhanced crystallinity compared to conventional synthesis methods.

Conclusions:

• Ligand electrostatic potential modulation offers a viable strategy for controlling 2D c-MOF stacking and crystallinity.
• Systematic tuning of stacking configurations provides a pathway for optimizing electrical performance in 2D c-MOFs.
• This work provides a rational design approach for developing advanced 2D c-MOF materials with tailored properties.