Formation and isolation of an iron-tripyrrole complex from heme degradation.
Addition of dioxygen to a solution of (py)2Fe(OEPO) (1) (where OEPO is the trianion of octaethyloxophlorin) in pyridine-d5 at 23 degrees C results in a series of oxidative changes that have been followed by 1H NMR spectroscopy. After 4 h, the resonances of 1 have vanished, while several sets of new resonances have developed. The most intense of these are identified as belonging to (py)2FeIII(OEB) (2) by comparison with the previously obtained spectrum of this species, which contains a ring-opened tetrapyrrole. After the sample was left standing for 1 day, further changes occur which produce a sample that is stable, because 1H NMR spectroscopic examination reveals no further changes on continued exposure to dioxygen or air. The product, (py)2FeIII(HETP) (3), where HETP is the dianion of a hexaethyltripyrrole, has been converted into (n-Bu4N)[ClFeIII(HETP)] by treatment with tetra(n-butyl)ammonium chloride. Red (n-Bu4N)[ClFeIII(HETP)] has been isolated and characterized by single-crystal X-ray diffraction.
Rath
Sankar Prasad
SP
Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.
Olmstead
Marilyn M
MM
Latos-Grazyński
Lechoslaw
L
Balch
Alan L
AL
D005290:Ferric Compounds / Q000737:chemistry* / Q000378:metabolism; D006418:Heme / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D011758:Pyrroles / Q000737:chemistry* / Q000378:metabolism; D014961:X-Ray Diffraction
D005290:Ferric Compounds; D011758:Pyrroles; D006418:Heme