Constructing a Two-Dimensional Electrically Conductive Metal–Organic Framework from a Ligand with Low In-Plane Rotational Symmetry

Two-dimensional electrically conductive metal–organic frameworks (2D c-MOFs) possess good charge transport and permanent porosity─a rare combination. This makes them attractive for applications ranging from energy storage to electrocatalysis. Despite this, the compositional and structural phase space available for the design of 2D c-MOFs is limited when compared to MOFs as a general class of materials. 2D c-MOFs have been assembled mostly from ligands with extended π conjugation and high in-plane rotational symmetry. This often results in predictable structures with geometrically neat 2D tiling patterns that have mostly uniform pore sizes. Here we report the synthesis of a 2D c-MOF constructed from a ligand, tetrahydroxyphenanthrenequinone (THPQ), having a single in-plane 2-fold axis of rotation. Consequently, THPQ has no rotational degeneracy, preventing deterministic tiling of two-dimensional space. The resulting MOF, Cu3(THPQ)2, has a local structure that resembles that of the well-known Cu3(HHTP)2; however, unlike Cu3(HHTP)2, the material reported here appears to exhibit random tiling in two dimensions. Despite considerable disorder both in-plane and in the direction of stacking, Cu3(THPQ)2 exhibits good electrical conductivity (1.306 × 10–5 S·cm–1). This work demonstrates the use of an asymmetric ligand to construct highly disordered 2D c-MOF and informs design principles for accessing more complex 2D tiling patterns.