Establishment of structure-conductivity relationship for tris(2,2'-bipyridine) ruthenium ionic C(60) salts

Three ionic C(60) salts with Ru(bpy)(3)](m+) (bpy = 2,2'-bipyridine) as cations were synthesized. The UV-vis-NIR spectra, XPS spectra, and elemental analysis have demonstrated their compositions: Ru(bpy)(3)](2)(C(60)) (1), Ru(bpy)(3)](C(60)) (2), and Ru(bpy)(3)](C(60))(2) (3). Single crystals of polycrystalline compounds 1 and 2 were obtained as solvates. At room temperature, all three salts are semiconducting with the highest four-probe conductivity observed for compound 1 at ～10 S m(-1). The electronic conduction mechanisms can be described appropriately by an electron hopping model in this immobilized polyvalent redox system.