Synthesis and solid-state molecular structures of nitrosoalkane complexes of iron porphyrins containing methanol, pyridine, and 1-methylimidazole ligands

J Inorg Biochem. 2004 Jul;98(7):1238-46. doi: 10.1016/j.jinorgbio.2004.04.008.

Abstract

Nitrosoalkanes belong to the family of C-nitroso compounds and are known to bind to the iron center in heme proteins. We have prepared and characterized a series of new nitrosoalkane heme model complexes of the form (por)Fe(RNO)(L) (por=porphyrinato dianion; R=isopropyl; L=MeOH, pyridine, 1-methylimidazole) by infrared and 1H NMR spectroscopy and X-ray crystallography. Within the set of octaethylporphyrinato (OEP) compounds, the infrared stretching frequencies of the NO groups decrease in the order (OEP)Fe(iPrNO)(MeOH).MeOH (1433 cm-1) > (OEP)Fe(iPrNO)(py) (1429 cm-1) > (OEP)Fe(iPrNO)(1-MeIm) (1423 cm-1), reflecting the increased backdonation of electron density in the 1-methylimidazole derivative. The molecular structures of the compounds as determined by crystallography reveal N-binding of the nitrosoalkane ligands to the formally ferrous metal centers.

Publication types

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

MeSH terms

  • Heme / chemical synthesis*
  • Heme / chemistry
  • Imidazoles / chemistry*
  • Ligands
  • Methanol / chemistry*
  • Molecular Structure
  • Nitroso Compounds / chemical synthesis*
  • Nitroso Compounds / chemistry
  • Pyridines / chemistry*

Substances

  • Imidazoles
  • Ligands
  • Nitroso Compounds
  • Pyridines
  • Heme
  • pyridine
  • 1-methylimidazole
  • Methanol