A Low-Symmetry Copper Benzenehexathiol Coordination Polymer with In-Plane Electrical Anisotropy.

Electrically conductive coordination polymers (ECCPs), particularly those incorporating benzenehexathiol (BHT) ligands, are emerging as a distinctive class of electronic materials with tunable semiconducting and metallic properties. However, the exploration of novel ECCPs with low-symmetry structures and electrical anisotropy remains under development. Here, we report the on-water surface synthesis of a novel ECCP, namely CuBHT, which exhibits a low-symmetry structure and unique in-plane electrical anisotropy that differs from the well-known CuBHT phase. Utilizing imaging and diffraction techniques, we elucidate the unit cell and crystal structure of CuBHT, revealing an asymmetric arrangement of the kagome resembling lattice connected by two different secondary building units: square planar CuS and non-planar CuS. Theoretical studies indicate that CuBHT is metallic and exhibits in-plane electrical anisotropy due to the structure arranged in interconnected well-conducting CuS chains and less-conducting CuS slabs oriented along single crystal direction. Single-crystal electrical measurements confirm a metallic character characterized by the increase of conductance upon cooling. Notably, the measured conductance along different crystal directions within the ab plane unambiguously reveals a significant anisotropy, with an anisotropic factor reaching ~8. This work demonstrates a novel low-symmetry ECCP and highlights its potential for achieving in-plane electrical anisotropy.