Electrooxidation of [Ni(dmit)2]-(dmit = C3S52- = 4,5-dithiolate-2-thione-1,3-dithiole) in 3:1 acetonitrile-acetone at a Pt wire anode in the presence of methyltriphenylphosphonium bromide electrolyte yields the radical anion salt complex [MePh3P][Ni(dmit)2]3. Black shiny platelet crystals were harvested. They belong to the monoclinic space group P21/c, M = 1631.41, a = 21.0872(1), b = 17.4930(2), c = 15.7203(2) Å, β = 107.072(1)°, V = 5543.4(1) Å3 and Z=4. The crystal packing structure consists of columns of Ni(dmit)2 units of width one unit separated by columns of MePh3P+ counter-ions. The Ni(dmit)2 columns are composed of dimers of Ni(dmit)2 units with non-bonding interactions with six other pairs of Ni(dmit)2 units. The arrangement of the dimers with respect to each other in the columns has been seen in other phosphonium-based Ni(dmit)2 complexes and is similar to the packing of κ-BEDT-TTF radical cation salts which have shown superconductivity. Single-crystal temperature-dependent conductivity measurements have shown that this material is semiconducting with a room-temperature conductivity of 0.1 S cm-1 and a thermal activation energy of 0.22 eV.
ASJC Scopus subject areas
- Materials Chemistry