Benzenehexol‐Based 2D Conjugated Metal–Organic Frameworks with Kagome Lattice Exhibiting a Metallic State

Abstract 2D conjugated metal–organic frameworks (2D c‐MOFs) are emerging as unique electroactive materials for electronics and spintronics. The structural design and discovery of Kagome‐type 2D c‐MOFs exhibiting a metallic state are of paramount significance, yet remain rarely explored. Here, the solution synthesis of benzenehexol‐based 2D c‐MOFs based is presented on the tetrahydroxy‐1,4‐quinone (THQ) ligand. This study shows that controlling the pH of the reaction system to ≈7.5 yields an energetically favorable nonporous Cu 3 (C 6 O 6 ) with a Kagome lattice, while at a pH of ≈10, the known porous Cu 3 (C 6 O 6 ) 2 with a honeycomb lattice is obtained. The crystal structures of both Cu 3 (C 6 O 6 ) 2 and Cu 3 (C 6 O 6 ) are resolved with near‐atomic precision (resolution, 1.8 Å) using an imaging technique. Unlike the p ‐type semiconducting behavior of Cu 3 (C 6 O 6 ) 2 , theoretical studies identify Cu 3 (C 6 O 6 ) as a metal due to its unique structural topology. The metallic state of Cu 3 (C 6 O 6 ) is experimentally validated by terahertz time‐domain spectroscopy (THz‐TDS), which shows an increase in conductivity upon cooling. Scattering‐type scanning near‐field optical microscopy (s‐SNOM) measurements further support these findings by revealing an increase in normalized reflectivity with decreasing temperature. This work provides a new avenue for tailoring the structural topology of 2D c‐MOFs to attain the Kagome lattice and metallic state.