title: A mixed-valence octanuclear iron-oxo pyrazolate: assessment of electronic delocalization by structural and spectroscopic analysis.
abstract: A formally Fe(III)(7)Fe(II) complex, containing an inner Fe(4)O(4)-cubane and four peripheral Fe centers, is derived from the one-electron reduction of its Fe(III)(8) precursor. Spectroscopic analysis of the former reveals that the redox activity of this Fe(8) system is confined within its cubane core. The resulting (Fe(4)O(4))(3+)-cubane, which is valence-delocalized in the NMR, Mössbauer, and IR spectroscopy time scales but valence-trapped in the X-ray photoelectron spectroscopy (XPS) time scale, is better described as a Robin-Day class-II system by the analysis of its near-infrared (NIR) intervalence charge transfer (IVCT) band profile.
authors.affiliation: Department of Chemistry and the Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931-3346.
authors.forename: Indranil
authors.initials: I
authors.lastname: Chakraborty
authors.forename: Peter
authors.initials: P
authors.lastname: Baran
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Sanakis
authors.forename: Athanassios
authors.initials: A
authors.lastname: Simopoulos
authors.forename: Esteban
authors.initials: E
authors.lastname: Fachini
authors.forename: Raphael G
authors.initials: RG
authors.lastname: Raptis
mesh_terms: D003198:Computer Simulation; D018360:Crystallography, X-Ray / Q000379:methods; D004581:Electronics; D007501:Iron / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D011720:Pyrazoles / Q000737:chemistry*; D015204:Spectroscopy, Mossbauer / Q000379:methods; D013057:Spectrum Analysis / Q000379:methods
chemical_list: D011720:Pyrazoles; D007501:Iron