Resonance Raman Structural Characterization of .beta.-Substituted Metalloporphyrins .pi.-Anion Radicals: Nature of the Jahn-Teller Effect

Hu, Songzhou; Lin, Che; Blackwood, Milton E.; Mukherjee, Arka; Spiro, Thomas G.

doi:10.1021/j100024a009

Cited by 25 publications

(41 citation statements)

References 7 publications

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“…T h e o r i g i n s o f t h e s e v i b r a t i o n s a r e to be totally . symmetric vibrations of a ZnP ring with 1130-1580 cm -1 due to stretching vibration of C-C, C=C and/or C-N bonds, according to Raman spectroscopy [18,19]. One should note here that the vibrational spacing is fairly small in the fluorescence from S2 relative to the Si emission.…”

Section: Discussionmentioning

confidence: 89%

Ultrafast Energy Relaxation and Excitation Delocalization in Excited States of Zinc Porphyrin Dimers and Trimer

et al. 1999

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Ultrafast excited-state relaxation process has been studied with zinc porphyrin dimers and circular trimer. Following 80 fs excitation at Soret band (420 nm) or Q band (580 nm) of zinc porphyrin, the fluorescence decay curves exhibit ultrafast decays with lifetimes of 80 fs in o-dimer, 450 fs in trimer and 540 fs in m-dimer. The time-resolved fluorescence spectra show that the fast decay process correspónd to disappearance of monomer-like emission followed by red-shifted and broaden spectra. These ultrafast processes are assigned as due to excitation transfer among monomers and delocalization of excitation yielding excitonic states.

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Section: Discussionmentioning

confidence: 89%

Ultrafast Energy Relaxation and Excitation Delocalization in Excited States of Zinc Porphyrin Dimers and Trimer

et al. 1999

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“…7 The ZnOEP LUMO is antibonding for both C R C and C R N on two of the four pyrrole rings. Moreover, ν 29 is a B 2g symmetry mode and can participate in the J-T distortion (although the B 2g contribution to the distortion is minor).…”

Section: Discussionmentioning

confidence: 99%

Resonance Raman Spectroscopic Characterization of the π-Anion and π-Cation Radicals of Zinc(II) Octaethylchlorin

Blackwood

Spiro

1997

J. Phys. Chem. B

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Cyclic voltammetry (CV), UV-vis spectroscopy, and resonance Raman (RR) spectroscopy are utilized to characterize the π-anion and π-cation radicals of ZnOEC (OEC ) octaethylchlorin). Features in the RR spectra are assigned with the aid of data from the meso-d 4 isotopomer of ZnOEC and ZnEtI (EtI ) etiochlorin I). The vibrational frequency shift patterns of the radicals are consistent with expected bonding changes on placing an electron in the LUMO or a hole in the HOMO. The frontier orbitals are similar in ZnOEC and ZnOEP (OEP ) octaethylporphyrin), but the anion spectra differ because of the consequences of the JahnTeller effect in ZnOEP -. The cation and anion vibrational shifts do not add to give the shifts previously reported for the triplet state, indicating additional distortion upon triplet excitation.

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“…Zn(OEP) THF 408 538, 572 [7] Zn(OEP) − THF 452 [7] Zn ( The visible spectrum of Zn II OEPdione is shown in Fig. 1.…”

Section: Compound Solvent Soret Band (Nm) Other Bands (Nm) Referencesmentioning

confidence: 99%

“…On the other hand, Zn II (P) complexes are known to reduce to the porphyrin π-radical anion because zinc is a d 10 complex. Zinc porphyrins (octaethylporphyrin, OEP, and tetraphenylporphyrin, TPP) have been extensively studied by voltammetry [5] and spectroelectrochemistry [5], [6] and [7]. The resonance Raman spectroscopy of Zn(P) − has also been reported [7] and [8].…”

Section: Introductionmentioning

confidence: 99%

“…Zinc porphyrins (octaethylporphyrin, OEP, and tetraphenylporphyrin, TPP) have been extensively studied by voltammetry [5] and spectroelectrochemistry [5], [6] and [7]. The resonance Raman spectroscopy of Zn(P) − has also been reported [7] and [8]. Unlike the zinc complex, there have been fewer studies carried out on the reduction of Mn II (P) complex.…”

Section: Introductionmentioning

confidence: 99%

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Visible and infrared spectroelectrochemistry of zinc and manganese porphinones: Metal vs. porphyrin reduction

Tutunea

Atifi

2015

Journal of Electroanalytical Chemistry

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Abstract:The visible and infrared spectroelectrochemistry of zinc and manganese porphinones and porphinediones was carried out in THF solutions. The aim of this work was to use FTIR spectroelectrochemistry and DFT calculation to determine whether the reduction was centered predominantly on the metal or the macrocycle. For zinc(II), the first one-electron reduction must occur on the macrocyclic ring because the metal's d-orbitals are filled (d 10 ). The carbonyl bands on the macrocyclic ring were used to probe the electronic structure because they can be readily observed in the infrared spectra. The results of this study are complementary to previous spectroelectrochemical studies that have been reported for the iron and cobalt complexes of the same macrocycles. As expected for the formation of a π-NOT THE PUBLISHED VERSION; this is the author's final, peer-reviewed manuscript. The published version may be accessed by following the link in the citation at the bottom of the page. Chemistry, Vol. 744 (May 1, 2015): pg. 17-24. DOI. This article is © Elsevier and permission has been granted for this version to appear in e-Publications@Marquette. Elsevier does not grant permission for this article to be further copied/distributed or hosted elsewhere without the express permission from Elsevier. Journal of Electroanalytical2 radical anion species, significant downshifts in the carbonyl bands were observed. DFT calculations showed that the behavior of the porphinedione complexes were most sensitive to the electronic structure of the M(OEPdione) − species. If a M I species is formed, the two carbonyl groups will be downshifted by similar energies. For M II -radical anions, one carbonyl will be downshifted significantly, and the second one will be downshifted by a small amount. On the basis of this criterion, it was determined that cobalt(I) and iron(I) complexes were formed, while zinc and manganese formed π-radical anion species. The visible spectroelectrochemistry was also consistent with these electronic structures. Graphical abstract:The visible and infrared spectroelectrochemistry of zinc and manganese porphinones and porphinediones was carried out in THF solutions. The carbonyl bands on the macrocyclic ring were used to probe the electronic structure. DFT calculations showed that the shifts in the carbonyl bands of the porphinedione (OEPdione) complexes were sensitive to the electronic structure of the M(OEPdione) − species. On this basis, the oxidation state of the metal in these complexes could be assigned.

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Resonance Raman Structural Characterization of .beta.-Substituted Metalloporphyrins .pi.-Anion Radicals: Nature of the Jahn-Teller Effect

Cited by 25 publications

References 7 publications

Ultrafast Energy Relaxation and Excitation Delocalization in Excited States of Zinc Porphyrin Dimers and Trimer

Ultrafast Energy Relaxation and Excitation Delocalization in Excited States of Zinc Porphyrin Dimers and Trimer

Resonance Raman Spectroscopic Characterization of the π-Anion and π-Cation Radicals of Zinc(II) Octaethylchlorin

Visible and infrared spectroelectrochemistry of zinc and manganese porphinones: Metal vs. porphyrin reduction

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