Resonance Raman Spectroscopy of Porphin

Plus, R.; Lutz, Marc

doi:10.1080/00387017408067229

Cited by 22 publications

(6 citation statements)

References 11 publications

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“…In fact, recent observations on porphin suggested that the depolarization ratios of nontotally symmetric vibrations, with respect to ground state molecular symmetry, may fall below 0.75 on approaching the Soret resonance region [14]. Similar variations of depolarization ratios were also observed in other porphyrins [25,26].…”

Section: Depolarization Ratiossupporting

confidence: 58%

Resonance Raman spectra of chlorophyll in solution

Lutz

1974

J Raman Spectroscopy

128

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Resonance Raman (RR) spectra of chlorophyll a and b, and of pheophytin a and b in solution are presented and their main features discussed. Variations of intensities and depolarization ratios of RR bands of the chlorophylls were followed as a function of the excitation wavelength from 441.6 to 514.5. nm. A number of band assignments are proposed. The effect of the state of association on the RR spectra of chlorophyll was studied for some typical in vitro systems. These data are discussed in view of their relevancy to the study of chlorophyll associations in vivo.

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Section: Depolarization Ratiossupporting

confidence: 58%

Resonance Raman spectra of chlorophyll in solution

Lutz

1974

J Raman Spectroscopy

128

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“…For porphyrins, there have been many investigations in the field of vibrational and vibronic spectroscopy, − and the problems of interpretation of the vibrational spectra have been, in principle, resolved. For porphycenes, the corresponding studies are just beginning to emerge; however, the interpretation of vibrational structure is still lacking.…”

Section: Introductionmentioning

confidence: 99%

Electronic Spectra of Porphycenes in Rare Gas and Nitrogen Matrices

1998

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Fine-line electronic absorption and fluorescence spectra of porphycene and 2,7,12,17-tetra-n-propylporphycene have been measured in low-temperature nitrogen, argon, krypton, and xenon matrices. A well-resolved emission spectrum of porphycene was also obtained in an isotropic glassy matrix using the fluorescence line-narrowing technique. Analysis of the observed matrix spectral shifts enabled the assignment of the origin of the S0−S2 electronic transition. Vibrational frequencies have been obtained for the ground and two lowest excited singlet states. Vibronic and site structure in the region of S0−S1 and S0−S2 electronic transitions of porphycenes have been compared with the corresponding data for porphyrin. Both similarities and differences were observed. In particular, contrary to the case of porphyrin and its derivatives, no site structure was observed in the spectra of porphycenes in xenon and krypton matrices. This was explained by a model that takes into account different positions of the transition moment directions in the two chromophores with respect to the matrix cage. No evidence was obtained for the presence of the cis tautomeric forms of porphycene.

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“…Resonance Raman spectra of metalloporphyrin complexes have been extensively studied to reveal the molecular symmetry and the excitation profile of Raman scattered intensity. [2][3][4][5][6][7][8][9] In previous work from this laboratory, Raman lines associated primarily with the methine-bridge stretching vibrations were assigned empirically10 and the assignments were confirmed by normal coordinate calculations.11-13 The dependence of porphyrin vibrational frequencies upon the nature of the substituted metal ion has also been discussed in terms of a model which proposes either -electron interaction between metal and porphyrin14 or distortion of the porphyrin ring.15 These Raman studies, and previous infrared stud-ies16-18 as well, have been concerned mainly with the higher frequency modes (above 850 cm-1) of the porphyrin ring system.…”

Section: Introductionmentioning

confidence: 99%

Resonance Raman spectra of metallooctaethylporphyrins. Low frequency vibrations of porphyrin and iron-axial ligand stretching modes

Kitagawa¹,

Abe²,

Kyōgoku³

et al. 1976

J. Phys. Chem.

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Resonance Raman spectra of THE solutions of various metallooctaethylporphyrin complexes [M(OEP): M = Pd2+, Ni2+, Co2+, and Cu2+], their meso-deuterated derivatives [M(OEP)-d4: M = Ni2+ and Pd2+], [Fe3+(OEP)X: X = F, Cl, Br, and I], Fe3+(OEP)Cl-d4, and Fe3+(0EP)(Im)2C104 are measured in the frequency region below 850 cm-1. Vibrational modes corresponding to individual Raman lines are shown in terms of Cartesian displacement vectors which have been obtained from normal coordinate analysis of the observed Raman and infrared data of Ni(OEP) and Ni(OEP)-d4. On the basis of the normal coordinate calculations, only one vibrational mode (Big in D^h) of M(OEP) is deduced to show a large isotopic frequency shift. Further, depolarized Raman lines are found at 751 and 684 cm-1 for Ni(OEP) and Ni(OEP)-d4, respectively, and at 758 and 687 cm-1 for Pd(OEP) and Pd(OEP)-d4, respectively. The Raman lines due to Feaxial ligand stretching modes are assigned for some Fe complexes. In high-spin derivatives [Fe3+(OEP)X], the Fe-X stretching modes are assigned at 606,364, and 279 cm-1 when X = F, Cl, and Br, respectively, while for low-spin derivatives [Fe3+(OEP)L2], the L-Fe-L symmetric stretching mode gives rise to the Raman line at 290 cm-1 when L = imidazole. A rather intense and polarized Raman line is observed at around 670 cm-1 in spectra of M(OEP) derivatives excited with 488.0-nm radiation and its intensity depends apparently upon the geometrical structures of the complexes.

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Resonance Raman Spectroscopy of Porphin

Cited by 22 publications

References 11 publications

Resonance Raman spectra of chlorophyll in solution

Resonance Raman spectra of chlorophyll in solution

Electronic Spectra of Porphycenes in Rare Gas and Nitrogen Matrices

Resonance Raman spectra of metallooctaethylporphyrins. Low frequency vibrations of porphyrin and iron-axial ligand stretching modes

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