A mixed-valence octanuclear iron-oxo pyrazolate: assessment of electronic delocalization by structural and spectroscopic analysis

Inorg Chem. 2008 Dec 15;47(24):11734-7. doi: 10.1021/ic801459s.

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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Computer Simulation
  • Crystallography, X-Ray / methods
  • Electronics
  • Iron / chemistry*
  • Magnetic Resonance Spectroscopy / methods
  • Models, Molecular
  • Molecular Conformation
  • Oxidation-Reduction
  • Pyrazoles / chemistry*
  • Spectroscopy, Mossbauer / methods
  • Spectrum Analysis / methods

Substances

  • Pyrazoles
  • Iron