Preparation of Pt(II) and Pd(II) complexes coordinated with both a diimine ligand and a sulfur-rich dithiolate ligand and electrical conductivities of their oxidized species and X-ray crystal structure of Pd(N-butyl-pyridine-2-carbaldimine)(C3S5)

Pt(L)(C8H4S8) [L=2,2′-bipyridine (bpy) and N-butyl-pyridine-2-carbaldimine (Bu-pya); C8H4S82−=2-{(4,5-ethylenedithio)-1,3-dithiol-2-ylidene}-1,3-dithiol-4,5-dithionate(2-)], Pt(bpy)(C10–C6S8) [C10–C6S82−=2-{bis(dodecylthio)-1,3-dithiol-2-ylidene}-1,3-dithiol-4,5-dithiolate (2-)], Pd(Bu-pya)(C8H4S8), and Pd(Bu-pya)(C3S5) [C3S52−=4,5-disulfanyl-1,3-dithiol-2-thionate(2-)] were prepared. They showed intense electronic absorption bands due to an intramolecular mixed metal/ligand-to-ligand charge transfer transition which is sensitive to a solvent. They exhibit oxidation potentials of −0.18 and +0.35 V (versus Ag/Ag+) with oxidation of the dithiolate ligand. They were oxidized by iodine or TCNQ (7,7,8,8-tetracyano-p-quinodimethane) to afford [Pt(L)(C8H4S8)](I3)x (x=0.9–1.0), [Pt(L)(C8H4S8)](TCNQ)y (y=0.6–0.8) (L=bpy, Bu-pya and C10–C6S8) and [Pd(Bu-pya)(C8H4S8)]·I5.1 and [Pd(Bu-pya)(C8H4S8)](TCNQ)0.4. The [Pt(L)(C8H4S8)]-oxidized complexes behave as electrical conductors with conductivities of 1.4×10−5–6.5×10−3 S cm−1 measured for compacted pellets at room temperature, while the [Pd(Bu-pya)(C8H4S8)]-oxidized species exhibit conductivities of (1.4–3.2)×10−3 S cm−1. The X-ray crystal structure of Pd(Bu-pya)(C3S5) revealed a one-dimensional array of the molecules constructed with some sulfur–sulfur non-bonded contacts.