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

摘要

The heterometallic complexes trans-Cp(dppe)FeNCRu(o-bpy)CNFe(dppe)CpPF6(n) (1PF6(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. 1(3+)PF6(3) and 1(4+)PF6(4) are the one- and two-electron oxidation products of 1(2+)PF6(2), respectively. The investigated results suggest that 1PF6(3) is a ClassII mixed valence compound. 1PF6(4) after a thermal treatment at 400K shows an unusually delocalized mixed valence state of Fe-III-NC-Ru-III-CN-Fe-II, which is induced by electron transfer from the central Ru-II to the terminal Fe-III in 1PF6(4), which was confirmed by IR spectroscopy, magnetic data, and EPR and Mossbauer spectroscopy.