Abstract:The title salt, triphenyl(P,P,P-triphenylphosphineimidato-N)-phosphorus(1+) 1,3,5,7-tetrathia(1,5-S IV )-2, 4,6,8,4,6,, prepared by the literature method, is found by crystallography to be a 1:1 CH 3 CN solvate. Disorder exists for the N atoms of the anion. A VT crystal structure study was conducted at 100 K, 120 K, 140 K, 172 K, 200 K, 240 K and 280 K. The 100 K structure is superior, with only 10% of a second anion position oppositely-oriented w.r.t the diad axis of point group 2mm. At 120 K, an adjacent two-site disorder is encountered, but at higher temperatures three-site disorder with both opposite and adjacent placements of S 4 N 5 − ions is required w.r.t. the primary component. At 240 and especially 280 K, the anion nitrogen atoms appear fully scrambled amongst the six possible sites on the edges of an S 4 tetrahedron with 83.3% occupancy for each. The PPN + geometry does not show strong cation-cation interactions. However, there are numerous supramolecular contacts corresponding mostly to non-classical H-bonds between PPN + ions and S 4 N 5 − as well as CH 3 CN. The geometry of the anion is corroborated from B3LYP/6-311++G(3df) DFT calculations, and the infra-red spectrum was assigned with excellent agreement between experimental and calculated frequencies.
