Divergent Electrically Conductive Pathways in Yttrium-Based 2- and 3-Dimensional Metal-Organic Frameworks

Despite most porous framework solids exhibiting insulating character, some are known to conduct electrical charge. The peak performing conductive metal-organic frameworks are composed of redox-active hexasubstituted triphenylene linkers, but the impact of redox activity on material conductivity remains enigmatic because of limited availability of direct structure-function relationships. Here, we report a hexagonal yttrium-based conductive porous scaffold, comprising hexahydroxytriphenylene connected by Y-chains (YHOTP). In comparison to its known porous cubic counterpart (Y₆HOTP₂), this material features a 1000-fold increase in peak conductivity in polycrystalline samples (∼10^-1 S cm^-1). Furthermore, through a comparison of their electronic structures, we rationalize the origin of this difference and highlight the role of charge carrier concentration in dictating bulk electrical conductivity. Together, this work provides a design principle for the development of next-generation conductive porous frameworks.