Speciation and structure of ferriprotoporphyrin IX in aqueous solution: spectroscopic and diffusion measurements demonstrate dimerization, but not μ-oxo dimer formation

@article{Villiers2006SpeciationAS,
  title={Speciation and structure of ferriprotoporphyrin IX in aqueous solution: spectroscopic and diffusion measurements demonstrate dimerization, but not μ-oxo dimer formation},
  author={Katherine A. de Villiers and Catherine H. Kaschula and Timothy J Egan and Helder M Marques},
  journal={JBIC Journal of Biological Inorganic Chemistry},
  year={2006},
  volume={12},
  pages={101-117}
}
Changes in ε 393 (the Soret band) of aqueous ferriprotoporphyrin IX [Fe(III)PPIX] with concentration indicate that it dimerizes, but does not form higher aggregates. Diffusion measurements support this observation. The diffusion coefficient of aqueous Fe(III)PPIX is half that of the hydrated monomeric dicyano complex. Much of the apparent instability of aqueous Fe(III)PPIX solutions could be attributed to adsorption onto glass and plastic surfaces. However, ε 347 was found to be independent of… CONTINUE READING