Molecular Curvature Enables Tubular π-Stacked Pathways in Three-Dimensional Conductive Metal-Organic Frameworks

Abstract

Conductive metal-organic frameworks (MOFs) are commonly constructed from planar aromatic ligands, whose geometries favor conventional π-stacking arrangements. However, intrinsically twisted ligands offer an alternative geometric approach to directing aromatic packing and constructing unconventional framework architectures. Here, we employ intrinsically twisted, butterfly-shaped dibenzo[g,p]chrysene-2,3,6,7,10,11,14,15-octaol (DBC) ligands to construct a series of lanthanide MOFs. Single-crystal X-ray diffraction reveals an interpenetrated three-dimensional framework in which π-π interactions between the aromatic fragments generate axially extended tubular π-stacked pathways, alongside one-dimensional channels rich in hydrogen-bonding sites. Lanthanide substitution preserves the overall tubular framework topology while modulating aromatic stacking distances and local pore environments. PrDBC single crystals exhibit mixed electron-proton transport, with electron and proton conductivities reaching 1.62 x 10-3 and 4.37 x 10-4 S cm-1, respectively, at 338 K and 30% relative humidity. This work highlights molecular curvature as a structural design strategy for constructing three-dimensional conductive MOFs that integrate tubular aromatic stacks with tunable pore environments for mixed electron-proton transport.