Polarized X-ray Absorption Near-Edge Structure of Highly Oxidized Chromium Porphyrins

James E. Penner-Hahn; M. Benfatto; B. Hedman; T. Takahashi; S. Doniach; John Taylor Groves; Keith O. Hodgson

doi:10.1021/ic00233a032

Polarized X-ray Absorption Near-Edge Structure of Highly Oxidized Chromium Porphyrins

James E. Penner-Hahn, M. Benfatto, B. Hedman, T. Takahashi, S. Doniach, John Taylor Groves, Keith O. Hodgson

Research output: Contribution to journal › Article › peer-review

38 Scopus citations

Abstract

Polarized X-ray absorption near-edge spectra have been measured for Cr^IV(TTP)O and Cr^v(TTP)N (TTP is the dianion of 5, 10, 15, 20-tetra-p-tolylporphyrin). These spectra, which are very similar for the two molecules, show an intense preedge absorption feature polarized perpendicular to the porphyrin plane. The absorption edges are relatively featureless when the polarization is parallel to the porphyrin plane. On the basis of multiple-scattered-wave X_α calculations, the intense preedge feature is interpreted as a bound→bound transition with significant metal character in the excited state. This transition, which has been observed in many metal—oxo species, was not observed in the putative ferryl (Fe═O) intermediates of horseradish peroxidase. The reasons for this absence in Fe═O species and its relationship to the reactivity of metal—oxo porphyrin complexes are discussed in light of the present results.

Original language	English (US)
Pages (from-to)	2255-2259
Number of pages	5
Journal	Inorganic Chemistry
Volume	25
Issue number	13
DOIs	https://doi.org/10.1021/ic00233a032
State	Published - Jun 1986

All Science Journal Classification (ASJC) codes

Physical and Theoretical Chemistry
Inorganic Chemistry

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10.1021/ic00233a032

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title = "Polarized X-ray Absorption Near-Edge Structure of Highly Oxidized Chromium Porphyrins",

abstract = "Polarized X-ray absorption near-edge spectra have been measured for CrIV(TTP)O and Crv(TTP)N (TTP is the dianion of 5, 10, 15, 20-tetra-p-tolylporphyrin). These spectra, which are very similar for the two molecules, show an intense preedge absorption feature polarized perpendicular to the porphyrin plane. The absorption edges are relatively featureless when the polarization is parallel to the porphyrin plane. On the basis of multiple-scattered-wave Xα calculations, the intense preedge feature is interpreted as a bound→bound transition with significant metal character in the excited state. This transition, which has been observed in many metal—oxo species, was not observed in the putative ferryl (Fe═O) intermediates of horseradish peroxidase. The reasons for this absence in Fe═O species and its relationship to the reactivity of metal—oxo porphyrin complexes are discussed in light of the present results.",

author = "Penner-Hahn, {James E.} and M. Benfatto and B. Hedman and T. Takahashi and S. Doniach and Groves, {John Taylor} and Hodgson, {Keith O.}",

year = "1986",

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language = "English (US)",

volume = "25",

pages = "2255--2259",

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publisher = "American Chemical Society",

number = "13",

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T1 - Polarized X-ray Absorption Near-Edge Structure of Highly Oxidized Chromium Porphyrins

AU - Penner-Hahn, James E.

AU - Benfatto, M.

AU - Hedman, B.

AU - Takahashi, T.

AU - Doniach, S.

AU - Groves, John Taylor

AU - Hodgson, Keith O.

PY - 1986/6

Y1 - 1986/6

N2 - Polarized X-ray absorption near-edge spectra have been measured for CrIV(TTP)O and Crv(TTP)N (TTP is the dianion of 5, 10, 15, 20-tetra-p-tolylporphyrin). These spectra, which are very similar for the two molecules, show an intense preedge absorption feature polarized perpendicular to the porphyrin plane. The absorption edges are relatively featureless when the polarization is parallel to the porphyrin plane. On the basis of multiple-scattered-wave Xα calculations, the intense preedge feature is interpreted as a bound→bound transition with significant metal character in the excited state. This transition, which has been observed in many metal—oxo species, was not observed in the putative ferryl (Fe═O) intermediates of horseradish peroxidase. The reasons for this absence in Fe═O species and its relationship to the reactivity of metal—oxo porphyrin complexes are discussed in light of the present results.

AB - Polarized X-ray absorption near-edge spectra have been measured for CrIV(TTP)O and Crv(TTP)N (TTP is the dianion of 5, 10, 15, 20-tetra-p-tolylporphyrin). These spectra, which are very similar for the two molecules, show an intense preedge absorption feature polarized perpendicular to the porphyrin plane. The absorption edges are relatively featureless when the polarization is parallel to the porphyrin plane. On the basis of multiple-scattered-wave Xα calculations, the intense preedge feature is interpreted as a bound→bound transition with significant metal character in the excited state. This transition, which has been observed in many metal—oxo species, was not observed in the putative ferryl (Fe═O) intermediates of horseradish peroxidase. The reasons for this absence in Fe═O species and its relationship to the reactivity of metal—oxo porphyrin complexes are discussed in light of the present results.

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JO - Inorganic Chemistry

JF - Inorganic Chemistry

IS - 13

ER -

Polarized X-ray Absorption Near-Edge Structure of Highly Oxidized Chromium Porphyrins

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