Preparation and Oxidation of Pt(II) Complexes Containing Both C-Deprotonated 2-Phenylpyridine (ppy−) and a Sulfur-Rich Dithiolate Ligand and X-ray Crystal Structure of [NBun4][Pt(ppy)(C8H4S8)]

[NEt4][Pt(ppy)(C3S5)] (ppy− = C-deprotonated 2-phenylpyridine(−); C3S52− = 4,5-disulfanyl-1,3-dithiole-2-thionate(2−)), [NEt4]-, [NBun4][Pt(ppy)(C8H4S8)] (C8H4S82− = 2-{(4,5-ethylenedithio)-1,3-dithiole-2-ylidene}-1,3-dithiole-4,5-dithiolate(2−)) and [NEt4][Pt(ppy)(C10–C6S8)] (C10–C6S82− = 2-{bis(decylthio)-1,3-dithiole-2-ylidene}-1,3-dithiole-4,5-dithiolate(2−)) were prepared. They showed an intense electronic absorption band due to an intramolecular mixed metal/dithiolate ligand-to-ppy ligand charge transfer transition, which is somewhat sensitive to the solvent. The complexes exhibited first oxidation potentials of −0.27 to +0.02 V (vs Ag/Ag+) due to the dithiolate ligand-centered oxidation. They were oxidized by TCNQ and iodine to afford [Pt(ppy)(L)] and [Pt(ppy)(L)](I1.0–4.2) (L = C3S52−, C8H4S82−, and C10–C6S82−). Electrical conductivities of the oxidized C8H4S8- and C10–C6S8-species measured for compacted pellets at room temperature were 6.2 × 10−6–7.8 × 10−3 S cm−1, while those of the oxidized C3S5-species were very low [(3.8–6.2) × 10−9 S cm−1]. The X-ray crystal structure of [NBun4][Pt(ppy)(C8H4S8)] was clarified.