Asymmetrical Substitution Manipulates Stacking Modes in 2D Conductive MOF Crystals

The stacking modes in two-dimensional conductive metal-organic frameworks (2D c-MOFs) serve as a pivotal design parameter for precisely controlling charge transport pathways, thereby directly regulating carrier mobility and anisotropic transport. Precise control over the stacking modes of atomically precise single-crystal structures of 2D c-MOFs through the bottom-up synthesis remains a major challenge. The reason lies in the dominant role of coordination bonds during 2D c-MOF synthesis, where the weak van der Waals interactions between ligands are often overridden and fail to be expressed in the final MOF architecture. Moreover, most 2D c-MOFs can only be obtained as nanocrystalline powders, making it difficult to obtain precise structural information. Here, we report a new strategy for achieving controllable stacking and enhanced crystallinity in 2D c-MOFs through the asymmetrical electrostatic potential modulation of ligands. By strategically substituting fluorine atoms into the hexahydroxytriphenylene (HHTP) ligands, we modulated the intrinsic charge distribution, enabling the synthesis of two HHTP derivatives with different packing modes. The c-MOF crystals synthesized through this approach exhibit distinct stacking modes and tunable electrical properties. Through the systematic modulation of ligand stacking configurations, this work elucidates fundamental structure-property correlations in 2D c-MOFs, providing a rational design strategy for tailoring 2D c-MOF materials with optimized performance characteristics.