Macrocycle and substituent vibrational modes of nonplanar nickel(II) octaethyltetraphenylporphyrin from its resonance Raman, near-infrared-excited FT Raman, and FT-IR spectra and deuterium isotope shifts

Stichternath, Andreas; Schweitzer‐Stenner, Reinhard; Dreybrodt, Wolfgang; Mak, Ronald S.W.; Li, Xiaoyuan; Sparks, Laurie D.; Shelnutt, John A.; Medforth, Craig J.; Smith, Kevin M.

doi:10.1021/j100117a012

Cited by 28 publications

(27 citation statements)

References 4 publications

(4 reference statements)

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“…Furthermore, our assignment of ν′ 7 and ν 6 is also more convincing because ν 6 is generally the mode exhibiting a comparably large shift upon 15 N 4 isotopic substitution. 19,25 This requirement is not met by the assignment suggested by Piffat et al 17 The mode assignment of Stichternath et al 16 is also not satisfying in this respect, because they also attributed the line at 731 cm -1 to ν 7 . According to these authors, the ν 6 appears as a relatively weak line at 849 cm -1 .…”

Section: Resultsmentioning

confidence: 97%

“…Our assignments and designations are not identical for all modes with that of Piffat et al 17 These authors have considered the γ 16 as a substituent mode. Consequently, they designated 314 cm -1 mode as γ 16 . The mode nomenclature is also different for the A 1g type vibrations ν 6 and ν 7 .…”

Section: Resultsmentioning

confidence: 99%

“…Its Raman lines were first assigned by Stichternath et al based on polarized resonance Raman, FT-Raman, and FT-IR spectra of the natural abundance and the derivative with deuterated phenyl groups. 16 Somewhat later, Piffat et al 17 suggested an assignment based on a normal-mode analysis for a planar model configuration. Both studies suggested basically the same assignment but differ with respect to a few Raman lines.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A New Method for Evaluating the Conformations and Normal Modes of Macromolecule Vibrations with a Reduced Force Field. 2. Application to Nonplanar Distorted Metal Porphyrins

et al. 1999

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We have developed a novel method for molecular mechanics calculations and normal-mode analysis. It is based on symmetry of local units that constitutes the given molecule. Compared with general valence force field calculations, the number of free parameters is reduced by 40-80% in our procedure. It was found to reproduce very well the vibrational frequencies and mode compositions of aromatic compounds and porphyrins, as shown by comparison with DFT calculations. A slightly altered force field obtained from Ni(II) porphin was then used to calculate the structure and the normal modes of several meso-substituted Ni(II) porphyrins which are known to be subject to significant ruffling and/or saddling distortions. This method satisfactorily reproduces their nonplanar structure and Raman band frequencies in the natural abundance and isotopic derivative spectra. The polarization properties of bands from out-of-plane modes are in accordance with the predicted nonplanar distortions. Moreover, we found that some of the modes below 800 cm -1 which appear intense in the Raman spectra contain considerable contributions from both in-plane and out-of-plane vibrations, so that the conventional mode assignments become questionable. We also demonstrate that the intensity and polarization of some low-frequency Raman bands can be used as a (quantitative) marker to elucidate type and magnitude of out-of-plane distortions. These were recently shown to affect heme groups of hemoglobin, myoglobin, and, in particular, of cytochrome c.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A New Method for Evaluating the Conformations and Normal Modes of Macromolecule Vibrations with a Reduced Force Field. 2. Application to Nonplanar Distorted Metal Porphyrins

et al. 1999

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“…The measurement of the latter has also become easier in the last 10 years due to the availability of CCD cameras which allow quick spectral recording with a much better signal to noise than older spectrometers with a photomultiplier. Additionally, new computer software enables a thorough spectral analysis of complicated Raman spectra with various overlapping bands [40].…”

Section: Theoretical Modeling Of Reps Of Other Porphyrins In Solutionmentioning

confidence: 99%

“…13(b)). Stichternath et al [40] have first measured the DPDs and REPs of several Raman lines of NiOETPP which in their study served as a basis for mode assignment. The spectral data did not allow the discrimination between different conformers but the Voigtian character of the band profiles suggested inhomogenous broadening.…”

Section: Depolarization Ratio Dispersion As a Probe Of Asymmetric Dismentioning

confidence: 99%

Polarized resonance Raman dispersion spectroscopy on metalporphyrins

Schweitzer‐Stenner

2001

J. Porphyrins Phthalocyanines

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ABSTRACT:Resonance Raman spectroscopy is an ideal tool to investigate the structural properties of chromophores embedded in complex (biological) environments. This holds particularly for metalporphyrins which serve as prosthetic group in various proteins. Resonance Raman dispersion spectroscopy involves the measurement of resonance excitation and depolarization ratios of a large number of Raman lines at various excitation energies covering the spectral region of the chromophore's optical absorption bands. Thus, one obtains resonance excitation profiles and the depolarization ratio dispersion of these bands. While the former contains information about the structure of excited electronic states involved in the Raman scattering process, the latter reflects asymmetric perturbations which lower the porphyrin macrocycle symmetry from ideal D 4h . The article introduces and compares different quantum mechanical approaches designed to quantitatively analyze both resonance excitation and the relationship between symmetry lowering and depolarization ratio dispersion.

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Applications in Coordination Chemistry

Nakamoto

2008

Infrared and Raman Spectra of Inorganic and Coordination Compounds

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Macrocycle and substituent vibrational modes of nonplanar nickel(II) octaethyltetraphenylporphyrin from its resonance Raman, near-infrared-excited FT Raman, and FT-IR spectra and deuterium isotope shifts

Cited by 28 publications

References 4 publications

A New Method for Evaluating the Conformations and Normal Modes of Macromolecule Vibrations with a Reduced Force Field. 2. Application to Nonplanar Distorted Metal Porphyrins

A New Method for Evaluating the Conformations and Normal Modes of Macromolecule Vibrations with a Reduced Force Field. 2. Application to Nonplanar Distorted Metal Porphyrins

Polarized resonance Raman dispersion spectroscopy on metalporphyrins

Applications in Coordination Chemistry

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