Haem complexes

Fig. 8. The proposed four transitions seen in high-spin Fe(III) haem-complexes...

The absorption spectra of the model complexes of haem a, made by Lemberg and his collaborators (134), have been taken to indicate that the high-spin Fe(III) haem a complexes have absorption bands at 660 mp while the low-spin Fe(III) haem complexes have bands at 595 mp (135). These data allow an analysis of the spin-states of the cytochromes a. The analysis has been carried out by Williams (135), Vanneste (136), Williams, Lemberg and Cutler (137). 

A different class of iron compounds, viz. model haem complexes (Por)Fe(PMc3)(L ) (Por = substituted porphyrins), were studied by Walker et using a selective double-resonance technique in connection with isotopic enrichment of Fe. The complexes display a linear correlation between S Fe and 5 P of the phosphine ligand, and the variation of iron chemical shifts could be explained in terms of electronic d-d transition energies. 

The NO-adduct of the di haem of cdi nitrite reductase from Pseudomonas aeruginosa gives vFe-N at 585 cm" - high for a ferrous haem complex. ... 

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