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.

SUBMITTER: Chakraborty I 

PROVIDER: S-EPMC4617381 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature