Unusual crystal structure and electrical properties of tetraphenylphosphonium-Ni(dmit)2

The structure and physical properties of TPP(tetraphenylphosphonium)13[Ni(dmit)2] complex were examined. The crystal has a layered structure where the conducting sheets of the dmit complex are separated by the layers of the large counter cation. Within the layer, two of the three Ni(dmit)2 species form a dimer which stacks in [010] direction. The remaining Ni(dmit)2 unit is disposed almost perpendicular to the stack and separates adjacent columns of Ni(dmit)2 dimers. The crystal shows a room- temperature conductivity of ca. 10 S/cm along the long axis (column direction) and a semiconducting temperature dependence below room temperature. The in-plane anisotropy of conductivity was of the order of 1:100. The magnetic susceptibility measurement showed Curie-like behavior below room temperature.