Tunable Charge Transport Properties Through Precise <i>π</i> ‐Stacking Modulation in Isostructural Porous Molecular Conductors

Abstract

Abstract Understanding the structure–property relationships in electrically conductive metal–organic frameworks (MOFs) is critical for their rational design toward practical applications. Since single crystals of MOFs with through‐space conductive π‐stacked columnar structures are relatively easy to obtain, their structures can be determined with high accuracy. However, elucidating those structure–property relationships without interference from carrier scattering and variations in carrier concentration remains challenging. Herein, we synthesized three isostructural porous molecular conductors (denoted as PMC‐3 ) via electrocrystallization using a redox‐active N,N’ ‐di(4‐pyridyl)‐1,4,5,8‐naphthalenetetracarboxdiimide (NDI‐py) ligand and ZnX 2 (X = Cl, Br, I). Single crystals of PMC‐3 exhibit high electrical conductivity (∼10 −3  S cm −1 ), comparable to the highest values reported for NDI‐based crystalline materials. Moreover, PMC‐3 serves as a model system for probing structure–property relationships in through‐space conductive MOFs, offering three key advantages. First, the absence of counterions, eliminating carrier scattering; second, identical carrier concentrations across the series, allowing isolation of the effects of π ‐stacking geometry on transport properties; and third, tunable π ‐stacking geometries via halide ligand substitution. As a result, a linear correlation between the lattice parameter along the stacking axis and intrinsic charge transport properties is revealed, representing a significant advance in understanding charge transport in through‐space conductive MOFs.