title: Three distinct redox states of an oxo-bridged dinuclear ruthenium complex.
abstract: A series of [{(terpy)(bpy)Ru}(μ-O){Ru(bpy)(terpy)}](n+) ([RuORu](n+), terpy=2,2';6',2''-terpyridine, bpy=2,2'-bipyridine) was systematically synthesized and characterized in three distinct redox states (n=3, 4, and 5 for Ru(II,III)2, Ru(III,III)2, and Ru(III,IV)2, respectively). The crystal structures of [RuORu](n+) (n=3, 4, 5) in all three redox states were successfully determined. X-ray crystallography showed that the Ru-O distances and the Ru-O-Ru angles are mainly regulated by the oxidation states of the ruthenium centers. X-ray crystallography and ESR spectra clearly revealed the detailed electronic structures of two mixed-valence complexes, [Ru(III)ORu(IV)](5+) and [Ru(II)ORu(III)](3+), in which each unpaired electron is completely delocalized across the oxo-bridged dinuclear core. These findings allow us to understand the systematic changes in structure and electronic state that accompany the changes in the redox state.
authors.affiliation: Institute for Molecular Science (IMS), 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787 (Japan); Department of Chemistry, Faculty of Science, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Current address: Department of Chemistry, Faculty of Science, Hokkaido University, North-10 West-8, Kita-ku, Sapporo 060-0810 (Japan).
authors.forename: Masaki
authors.initials: M
authors.lastname: Yoshida
authors.forename: Mio
authors.initials: M
authors.lastname: Kondo
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Nakamura
authors.forename: Ken
authors.initials: K
authors.lastname: Sakai
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Masaoka
mesh_terms: D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D010084:Oxidation-Reduction; D066244:Proton Magnetic Resonance Spectroscopy; D017975:Ruthenium Compounds / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D017975:Ruthenium Compounds
keywords: charge distribution; mixed-valence compounds; multiple bonds; ruthenium; μ-oxo complexes