Convenient small-scale method for the insertion of iron into porphyrins

Landergren, Marie; Baltzer, Lars

doi:10.1021/ic00328a045

Cited by 28 publications

(32 citation statements)

References 5 publications

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“…39 The 95% 57 Fe 2 O 3 used in the 57 Fe labeled complexes was purchased from Cambridge Isotopes. All imidazoles were purchased from Sigma-Aldrich.…”

Section: Methodsmentioning

confidence: 99%

Effects of Imidazole Deprotonation on Vibrational Spectra of High-Spin Iron(II) Porphyrinates

Peng

Silvernail

et al. 2013

Inorg. Chem.

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The effects of the deprotonation of coordinated imidazole on the dynamics of five-coordinate high-spin iron(II) porphyrinates have been investigated using nuclear resonance vibrational spectroscopy. Two complexes have been studied in detail with both powder and oriented single-crystal measurements. Changes in the vibrational spectra are clearly related to structural differences in the molecular structures that occur when imidazole is deprotonated. Most modes involving the simultaneous motion of iron and imidazolate are unresolved but the one mode that is resolved is found at higher frequency in the imidazolates. These out-of-plane results are in accord with earlier resonance Raman studies of heme proteins. We also show the imidazole vs. imidazolate differences in the in-plane vibrations that are not accessible to resonance Raman studies. The in-plane vibrations are at lower frequency in the imidazolate derivatives; the doming mode shifts are inconclusive. The stiffness, an experimentally determined force constant that averages the vibrational details to quantify the nearest-neighbor interactions, confirms that deprotonation inverts the relative strengths of axial and equatorial coordination.

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“…39 The 95% 57 Fe 2 O 3 used in the 57 Fe labeled complexes was purchased from Cambridge Isotopes. All imidazoles were purchased from Sigma-Aldrich.…”

Section: Methodsmentioning

confidence: 99%

Effects of Imidazole Deprotonation on Vibrational Spectra of High-Spin Iron(II) Porphyrinates

Peng

Silvernail

et al. 2013

Inorg. Chem.

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“…33 The 57 Fe 2 O 3 used in the 57 Fe labeled complexes was purchased from Cambridge Isotopes. All imidazoles were purchased from Sigma-Aldrich.…”

Section: Methodsmentioning

confidence: 99%

Nuclear Resonance Vibrational Spectra of Five-Coordinate Imidazole-Ligated Iron(II) Porphyrinates

Barabanschikov

et al. 2012

Inorg. Chem.

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Nuclear resonance vibrational spectra have been obtained for six five-coordinate imidazole-ligated iron(II) porphyrinates, [Fe(Por)(L)] (Por = tetraphenylporphyrinate, octaethylporphyrinate, tetratolylporphyrinate or protoporphyrinate IX and L = 2-methylimidazole or 1,2-dimethylimidazole). Measurements have been made on both powder and oriented crystal samples. The spectra are dominated by strong signals around 200–300 cm−1. Although the in-plane and out-of-plane vibrations are seriously overlapped, oriented crystal spectra allow their deconvolution. Thus, oriented crystal experimental data, along with DFT calculations, enable the assignment of key vibrations in the spectra. Molecular dynamics are also discussed. The nature of the Fe–NIm vibrations has been elaborated further than was possible from resonance Raman studies. Our study suggests that the Fe motions are coupled with the porphyrin core and peripheral groups motions. Both peripheral groups and their conformations have significant influence on the vibrational spectra (position and shape).

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“…[21] Metalation of 95% 57 Fe enriched samples was prepared by a method similar to that of Landergren. [22] Mössbauer measurements were performed on a constant acceleration spectrometer with optional small field (Knox College). Samples for Mössbauer spectroscopy were prepared by immobilization in Apiezon M grease.…”

Section: Methodsmentioning

confidence: 99%

New Perspectives on Iron–Ligand Vibrations of Oxyheme Complexes

Peng

Barabanschikov

et al. 2011

Chemistry A European J

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We report our studies of the vibrational dynamics of iron for three imidazole-ligated oxyheme derivatives that mimic the active sites of histidine-ligated heme proteins complexed with dioxygen. The experimental vibrational data are obtained from nuclear resonance vibrational spectroscopy (NRVS) measurements conducted on both powder samples and oriented single-crystals, and which includes several in-plane (ip) and out-of-plane (oop) measurements. Vibrational spectral assignments have been made through a combination of the oriented sample spectra and predictions based on density functional theory (DFT) calculations. The twoFe–O2 modes that have been previously observed by resonance Raman spectroscopy in heme proteins are clearly shown to be very strongly mixed and are not simply either a bending or stretching mode. In addition, a third Fe–O2 mode, not previously reported, has been identified. The long-sought Fe–Im stretch, not observed in resonance Raman spectra, has been identified and compared with the frequencies observed for the analogous CO and NO species. The studies also suggest that the in-plane iron motion is anisotropic and is controlled by the orientation of the Fe–O2 group and not sensitive to the in the in-plane Fe–Np bonds and/or imidazole orientations.

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Convenient small-scale method for the insertion of iron into porphyrins

Cited by 28 publications

References 5 publications

Effects of Imidazole Deprotonation on Vibrational Spectra of High-Spin Iron(II) Porphyrinates

Effects of Imidazole Deprotonation on Vibrational Spectra of High-Spin Iron(II) Porphyrinates

Nuclear Resonance Vibrational Spectra of Five-Coordinate Imidazole-Ligated Iron(II) Porphyrinates

New Perspectives on Iron–Ligand Vibrations of Oxyheme Complexes

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