X-ray crystal structure and properties of tris(tetrathiafulvalenium) hexachloroplatinate

The title salt has been prepared by the diffusion of tetrathiafulvalene (TTF) and [NBuⁿ₄]₂[PtCl₆] in acetonitrile. Crystals (black plates) are tetragonal, space group P4/mbm, with a=11.757(2), c=11.707(2) Å, and Z=2. The block-diagonal least-squares refinement, based on 804 independent reflections with ∣F_o∣> 3σ(F), yields an R factor of 0.11. The structure is comprised of TTF-trimer units which are arranged perpendicularly to each other, forming a two-dimensional layer with somewhat close sulfur- sulfur contact among the trimers. The salt exhibits the electrical resistivity of 87 Ω cm as a compacted pellet at 25 °C. Binding energies of platinum 4f electrons of the [PtCl₆]²⁻ anion suggest an extreme reduction from the platinum(IV) state.