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

ABSTRACT

The heterometallic complexes trans-[Cp(dppe)FeNCRu(o-bpy)CNFe(dppe)Cp][PF6 ]n (1[PF6 ]n , 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. 13+ [PF6 ]3 and 14+ [PF6 ]4 are the one- and two-electron oxidation products of 12+ [PF6 ]2 , respectively. The investigated results suggest that 1[PF6 ]3 is a Class II mixed valence compound. 1[PF6 ]4 after a thermal treatment at 400 K shows an unusually delocalized mixed valence state of [FeIII -NC-RuIII -CN-FeII ], which is induced by electron transfer from the central RuII to the terminal FeIII in 1[PF6 ]4 , which was confirmed by IR spectroscopy, magnetic data, and EPR and Mössbauer spectroscopy.