Packing Order Control in Conductive Metal-Organic Frameworks by Tuning Ligand Oxidation State

Conductive metal-organic frameworks (c-MOFs), composed of metal nodes and redox-active ligands, have attracted growing interest due to the coexistence of porosity and charge transport. Notably, their electrical performance is closely related to the packing and ligand oxidation state within the framework, which has rarely been explored. Typical divalent metal nodes favor saturated intralayer square-planar coordination to ligands in a single oxidation state, thereby predetermining the framework topology. Here, we report a packing and topology control strategy, achieved by tuning the ligand oxidation state and grounded in lanthanides (e.g., Gd) versatile coordination chemistry. Diffuse reflectance spectroscopy and single-crystal transport measurements reveal that, at low temperature, coordination of Gd³⁺ with 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) in a lower mixed oxidation state (-4 and -5) yields a more ordered porous packing (Gd_1.5HHTP) with superior electronic transport performance. In contrast, at elevated temperature, the ligand adopts a higher oxidation state (-3), and coordination with Gd³⁺ yields a densely packed structure with local coordination disorder (GdHHTP), resulting in a markedly reduced electrical conductivity. This study demonstrates ligand-oxidation-state tuning provides an effective strategy for the precise control of structural order and charge transport in c-MOFs, laying a theoretical foundation for the rational design of materials with tunable electronic properties.