Diiron(II) mu-aqua-mu-hydroxo model for non-heme iron sites in proteins

Inorg Chem. 2005 Nov 28;44(24):8656-8. doi: 10.1021/ic051739i.

Abstract

We have synthesized a diiron(II) complex with a novel aqua-hydroxo bridging motif, [Fe2(mu-H2O)(mu-OH)(TPA)2](OTf)3 (1). This is a new member of the diiron diamond core family. The complex is stable in solution in nonpolar solvents as well as in the solid state. Two high-spin iron(II) sites are antiferromagnetically coupled (J = -9.6 cm(-1)). The drastic difference of ca. 1 V in the redox potential between complex 1 and its bis(hydroxo)-bridged analogue Fe2(OH)2(TPA)3+ is accompanied by only a moderate difference in the dioxygen reactivity. This observation is consistent with the inner-sphere mechanism of iron(II)-dioxygen association rather than the outer-sphere electron transfer.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Binding Sites
  • Chemistry, Inorganic / methods
  • Electrochemistry / methods
  • Electron Transport
  • Ferrous Compounds / chemistry*
  • Ferrous Compounds / metabolism
  • Heme / chemistry
  • Heme / metabolism
  • Iron / metabolism*
  • Ligands
  • Models, Molecular*
  • Molecular Conformation
  • Molecular Structure
  • Oxygen / chemistry
  • Proteins / chemistry
  • Proteins / metabolism*
  • Spectrometry, Mass, Electrospray Ionization / methods
  • Spectrophotometry, Ultraviolet
  • Temperature
  • Water

Substances

  • Ferrous Compounds
  • Ligands
  • Proteins
  • Water
  • Heme
  • Iron
  • Oxygen