An Unusually Delocalized Mixed-Valence State of a Cyanidometal-Bridged Compound Induced by Thermal Electron Transfer.

The heterometallic complexes trans-[Cp(dppe)FeNCRu(o-bpy)CNFe(dppe)Cp][PF ] (1[PF ] , n=2, 3, 4; o-bpy=1,2-bis(2,2'-bipyridyl-6-yl)ethane, dppe=1,2-bis(diphenylphosphino)ethane, Cp=1,3-cyclopentadiene) in three distinct states have been synthesized and fully characterized. 1 [PF ] and 1 [PF ] are the one- and two-electron oxidation products of 1 [PF ] , respectively. The investigated results suggest that 1[PF ] is a Class II mixed valence compound. 1[PF ] after a thermal treatment at 400 K shows an unusually delocalized mixed valence state of [Fe -NC-Ru -CN-Fe ], which is induced by electron transfer from the central Ru to the terminal Fe in 1[PF ] , which was confirmed by IR spectroscopy, magnetic data, and EPR and Mössbauer spectroscopy.