Effect of Metal Atom Perturbations on the Luminescent Spectra of Porphyrins

Allison, Jean B.; Becker, Ralph S.

doi:10.1063/1.1730932

Cited by 104 publications

(39 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The lowest triplet state, 1 3 E u , is located at 1.55 eV above the ground state at the CASPT2͑14/16͒ level, in agreement with the energy 1.6-1.7 eV determined from the phosphorescence spectra in EPA glass. 10,11 The most extensive calculation places the 2 3 E u state at 1.79 eV, that is, quite close in energy to the 1 3 E u state. The CASSCF description of the two lowest triplet E u states is dominated by one singly excited configuration: The 4a 2u →4e g with weight 81% in the 1 3 E u state and the 1a 1u →4e g ͑82%͒ for the 2 3 E u state.…”

Section: Resultsmentioning

confidence: 93%

“…The results are collected in Table VIII together with the experimental data coming from the phosphorescence spectra. 10,11 As can be seen in the table, the active space 4/4 provides too low CASPT2 excitation energies while the values obtained with the larger active spaces seem to be converged to Ϸ0.1 eV. The lowest triplet state, 1 3 E u , is located at 1.55 eV above the ground state at the CASPT2͑14/16͒ level, in agreement with the energy 1.6-1.7 eV determined from the phosphorescence spectra in EPA glass.…”

Section: Resultsmentioning

confidence: 99%

“…10,11 The effects of the substituents on the macrocycle in the visible and near-UV ͑ultraviolet͒ absorption bands were rationalized by Gouterman at the end of the fifties. 12 He also explained the differences between the spectra of free base porphins and metal-porphyrins using the cyclic polyene model introduced by Simpson.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Theoretical study of the electronic spectrum of magnesium-porphyrin

Rubio

Roos

Serrano‐Andrés

et al. 1999

The Journal of Chemical Physics

View full text Add to dashboard Cite

Multiconfigurational self-consistent field ͑SCF͒ and second order perturbation methods have been used to study the electronic spectrum of magnesium-porphyrin ͑MgP͒. An extended ANO-type basis set including polarization functions on all heavy atoms has been used. Four allowed singlet states of E 1u symmetry have been computed and in addition a number of forbidden transitions and a few triplet states. The results lead to a consistent interpretation of the electronic spectrum, where the Q band contains one transition, the B band two, and the N band one. The computed transition energies are consistently between 0.1 and 0.5 too low compared to the measured band maxima. The source of the discrepancy is the approximate treatment of dynamic correlation ͑second order perturbation theory͒, limitations in the basis set and the fact that all measurements have been made on substituted magnesium porphyrins.

show abstract

Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Theoretical study of the electronic spectrum of magnesium-porphyrin

Rubio

Roos

Serrano‐Andrés

et al. 1999

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…The 0-0 band in fluorescence emission is at 17492 cm-' [26] in Zn mesoporphyrin, at approximately 17 800 cm-' in Zn etioporphyrin [24] and at 17000 cm-' in Zn cytochrome c. However, in all three spectra, the most pronounced secondary bands are observed at a frequency difference 1540 -1550 cm-' from the 0-0 transition. It is interesting that one of the strong bands in the Raman spectrum of ferrous cytochrome c occurs at nearly the same frequency (1 548 cm-') [28,391, although in the latter technique the intensity of the transitions depends on the exciting wavelength.…”

Section: Properties Of Zinc and Tin Cytochrome Cmentioning

confidence: 99%

Metallocytochromes c : Characterization of Electronic Absorption and Emission Spectra of Sn4+ and Zn2+ Cytochromes c

1976

View full text Add to dashboard Cite

Tin (Sn4+) and zinc (Zn") derivatives of horse heart cytochrome c have been prepared and their optical spectra have been characterized. Zinc cytochrome c has visible absorption maxima at 549 and 585 nm and Soret absorption at 423 nm. Tin cytochrome c shows visible absorption maxima at 536 and 574 nm and Soret absorption at 410 nm. Unlike iron cytochrome c in which the emission spectrum of the porphyrin is almost completely quenched by the central metal, the zinc and tin derivatives of cytochrome c are both fluorescent and phosphorescent. The fluorescence maxima of zinc cytochrome c are at 590 and 640 nm and the fluorescence lifetime is 3.2 ns. The fluorescence maxima of Sn cytochrome are at 580 and 636 nm and the fluorescence lifetime is under 1 ns. The quantum yield of fluorescence is Zn > Sn while the quantum yield of phosphorescence is Sn > Zn.At 77 K the fluorescence and phosphorescence emission spectra of Sn and Zn cytochrome c show evidence of resolution into vibrational bands. The best resolved bands occur at frequency differences 750 cm-' and 1540-1550 cm-' from the 0-0 transition. These frequencies correspond with those obtained by resonance Raman spectroscopy for in-plane deformations of the porphyrin macrocycle.

show abstract

“…Our results show that the interaction between nonequivalent molecules in the unit cell of the compound increases from copper through nickel to cobalt in contrast with nickel through cobalt to copper. 8 We were unable to reproduce some of the results in DW and concluded, as these were obtained from un- B EFORE discussing the details of Fielding and MacKay's paper (referred to here as FM), we should like to draw attention to the two major facts about which there is no dispute. First the phthalocyanines show long-wavelength absorption bands outside the singlet regions previously investigated.…”

mentioning

confidence: 93%