In situ extended X-ray absorption fine structure of an iron porphyrin irreversibly adsorbed on an electrode surface

S. Kim, D. A. Tryk, I. T. Bae, M. Sandifer, R. Carr, M. R. Antonio, Daniel Alberto Scherson

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Abstract

The analysis of iron K-edge XAFS for hemoproteins is a subject of maturity in bioinorganic chemistry. The analysis of the in situ iron K-edge EXAFS reported here for 40% [Fe(TMPP)] 2 O adsorbed on BP as a function of solution pH and applied potential has benefit from this precedence. The results that clearly emerge are that d(Fe-N p ) is longer for the oxidized than for the reduced states. The range of d(Fe-N p ) for the oxidized macrocycles (2.05-2.08 A) is typical of high-spin Fe III , whereas the corresponding range for the reduced macrocycle (2.01-2.04 A) is smaller and typical of either high- and/or intermediate-spin Fe II . The μ-oxo dimer structure, [Fe(TMPP)] 2 O, is maintained from pH 5-11 for the oxidized material. At lower solution pH values (1.2-3.1), the smaller value of d(Fe-N p ) suggests the presence of a diaquo complex, [FeTMPP(OH 2 ) 2 ] + , whereas at higher pH values, i.e., 13, the dihydroxy species appears to predominate.

Original languageEnglish
Pages (from-to)10359-10364
Number of pages6
JournalJournal of physical chemistry
Volume99
Issue number25
DOIs
Publication statusPublished - 1995 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)
  • Physical and Theoretical Chemistry

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    Kim, S., Tryk, D. A., Bae, I. T., Sandifer, M., Carr, R., Antonio, M. R., & Scherson, D. A. (1995). In situ extended X-ray absorption fine structure of an iron porphyrin irreversibly adsorbed on an electrode surface. Journal of physical chemistry, 99(25), 10359-10364. https://doi.org/10.1021/j100025a044