Synthesis,structure and characterization of a new trinuclear magnetic semiconductor PbI4[Cu(Me2dtc)(bipy)]2

A new trinuclear magnetic lead iodide semiconductor PbI₄[Cu(Me₂dtc)(bipy)]₂ (Me₂dtc = N,N-dimethyldithiocarbamate, bipy = 2,2′-bipyridine) has been synthesized, and structurally characterized by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group P2₁/c with a = 22.2137(11) Å, b = 11.3687(4) Å, c = 15.3382(8) Å, β = 102.372(3)°, Z = 4, V = 3783.6(3) Å³. It is built up by [PbI₄S₂] octahedron linked with two [CuIS₂N₂] square pyramids through common edges. The adjacent molecules stack with each other to form a two-dimensional (2D) layer along ab plane via the π–π stacking interactions between aromatic groups of bipy ligands. Then the 2D layers are further extended into a three-dimensional structure through hydrogen bonding interactions. The temperature dependence of the electrical conductivity indicates that this compound exhibits semiconducting character. The title brown–black compound has an optical bandgap of 1.26 eV, and the variable-temperature magnetic susceptibility measurement indicates weak antiferromagnetic behavior with J = ?1.06 cm^?1.