Just a proton: distinguishing the two electronic states of five-coordinate high-spin iron(II) porphyrinates with imidazole/ate coordination

J Am Chem Soc. 2010 Mar 24;132(11):3737-50. doi: 10.1021/ja907584x.

Abstract

We report detailed studies on two S = 2 electronic states of high-spin iron(II) porphyrinates. These two states are exemplified by the five-coordinate derivatives with either neutral imidazole or anionic imidazolate as the axial ligand. The application of several physical methods all demonstrate distinctive differences between the two states. These include characteristic molecular structure differences, Mossbauer spectra, magnetic circular dichroism spectroscopy, and integer-spin EPR spectral distinctions. These distinctions are supported by DFT calculations. The two states are characterized by very different spatial properties of the doubly occupied orbital of the high-spin that are consonant with the physical properties.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Circular Dichroism
  • Crystallography, X-Ray
  • Electron Spin Resonance Spectroscopy
  • Electrons*
  • Imidazoles / chemistry*
  • Iron / chemistry*
  • Magnetics
  • Metalloporphyrins / chemistry*
  • Models, Molecular
  • Molecular Conformation
  • Protons*
  • Quantum Theory
  • Spectroscopy, Mossbauer

Substances

  • Imidazoles
  • Metalloporphyrins
  • Protons
  • imidazole
  • Iron