The two new radical anion salts [MePh3P] [Pd(dmit)2]3 (1) (dmit = C3S52 = 1,3-dithiole-2-thione-4,5-dithiolate) and [Ph4P]-[Pd(dmit)2]3 (2) have been synthesized and characterized by X-ray diffraction, elemental analysis and temperature-dependent conductivity measurements. Complexes 1 and 2 were prepared via electrooxidation of [Pd(dmit)2]2- in acetonitrile-acetone solvent mixtures at a Pt wire anode in the presence of methyltriphenylphosphonium bromide and tetraphenylphosphonium bromide electrolytes, respectively. For [MePh3P] [Pd(dmit)2]3 (1), black shiny needle and platelet crystals suitable for X-ray analysis were obtained. The crystal packing structure consists of layers of Pd(dmit)2 units separated by layers of MePh3P+ counterions. The Pd(dmit)2 layers are composed of dimers of Pd(dmit)2 units as a result of strong Pd⋯Pd interactions. Extensive S⋯S nonbonding interdimer intera ctions are observed, with each dimer interacting with six other adjacent dimers. For [Ph4P] [Pd(dmit)2]3 (2), black shiny flat needles were harvested and th e stoichiometry confirmed by elemental analysis. Single-crystal temperature-dependent conductivity measurements show that 1 behaves as a semiconductor with a room-temperature conductivity of 13 S cm-1 and a thermal activation energy of 100 meV. Compound 2 also displays semiconducting behavior with a room-temperature conductivity of 0.8-1 S cm-1 and a thermal activation energy of 55 meV.
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