The air-stable complex [Fe(6-Me3-TPA) (O2CAr)]+ [1; 6-Me3-TPA=tris(6-methyl-2-pyridylmethyl)amine] has been synthesized as a model for the iron(II) site of lipoxygenase. This iron(II) complex reacts with 0.5 equiv ROOH to form a yellow species, which has been formulated as [FeIII(OH)(6-Me3-TPA) (O2CAr)]+ (2) by electrospray mass spectrometry. Addition of more ROOH converts 2 into a purple species, which is characterized by electrospray ionization mass spectrometry and resonance Raman spectroscopy as [FeIII(OOR)(6-Me3-TPA)(O2CAr)]+. The purple species is metastable and decomposes via Fe-O bond homolysis to regenerate the starting iron(II) complex. These metal-centered transformations parallel the changes observed for lipoxygenase in its reaction with its product hydroperoxide.
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Acknowledgements This work has been supported by a grant from the National Institutes of Health (GM-33162 to L.Q.) and a postdoctoral fellowship from Fundacio “La Caixa” (to M.C.).
- Model compounds
- Nonheme iron
- Peroxo complexes