Polarization spectra of metalloporphyrins

Zalesskii, I. E.; Kotlo, V. N.; Соловьев, К. Н.; Shkirman, S. F.

doi:10.1007/bf00614152

Cited by 9 publications

(13 citation statements)

References 7 publications

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“…1) at the centre of the tetrapyrrole macrocycle is an observable phenomenon at low temperatures in the H 2 Pcs 35 and H 2 Ps. 31,[35][36][37] This effect provides a "photochemical" PSHB mechanism for these molecules. 38,39 Furthermore, for the symmetrical porphyrins and phthalocyanines the absorption band of the photoproduct is located within the envelope of the initial absorption band.…”

Section: F Hole-burningmentioning

confidence: 99%

Free base tetraazaporphine isolated in inert gas hosts: Matrix influence on its spectroscopic and photochemical properties

Henchy

McCaffrey

Arabei

et al. 2014

The Journal of Chemical Physics

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The absorption, fluorescence, and excitation spectra of free base tetraazaporphine (H 2 TAP) trapped in Ne, N 2 , and Ar matrices have been recorded at cryogenic temperatures. Normal Raman spectra of H 2 TAP were recorded in KBr discs and predicted with density functional theory (DFT) using large basis sets calculations. The vibrational frequencies observed in the Raman Spectrum exhibit reasonable agreement with those deduced from the emission spectra, as well as with frequencies predicted from large basis set DFT computations. The upper state vibrational frequencies, obtained from highly resolved, site selected excitation spectra, are consistently lower than the ground state frequencies. This contrasts with the situation in free base phthalocyanine, where the upper state shows little changes in vibrational frequencies and geometry when compared with the ground state. Investigations of the photochemical properties of H 2 TAP isolated in the three matrices have been performed using the method of persistent spectral hole-burning (PSHB). This technique has been used to reveal sites corresponding to distinct N-H tautomers which were not evident in the absorption spectra. An analysis of the holes and antiholes produced with PSHB in the Q x (0-0) absorption band made it possible to identify inter-conversion of distinct host sites. © 2014 AIP Publishing LLC.

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Section: F Hole-burningmentioning

confidence: 99%

Free base tetraazaporphine isolated in inert gas hosts: Matrix influence on its spectroscopic and photochemical properties

Henchy

McCaffrey

Arabei

et al. 2014

The Journal of Chemical Physics

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“…The experimental values of the S 4 -S 3 interval are determined from the fluorescence excitation QLS with high accuracy and constitute 245 cm -1 for site 1 and 318 cm -1 for site 2. Together with the data for TBP, for which the S 4 -S 3 interval is larger, but does not differ drastically (771 cm -1 for the shortwavelength site [9,13]), this allows one to infer that without the annelated benzene rings this interval should be still less. In other words, the splitting of the doubly degenerate B level (S 3,4 ) of the initial D 4h porphine macrocycle on the introduction of two imino hydrogens in its center is not great (on the order of 100 cm -1 ).…”

Section: On the Nature Of The Soret Band Of Freebase Porphyrinsmentioning

confidence: 62%

“…The spectral-luminescent properties of TBP, predominantly, the quasi-line spectra (QLS) of fluorescence and absorption, were the subject of a number of studies in our group [5][6][7][8][9][10][11][12][13][14][15]. In the work of Maslov [16] the method of photochemical persistent hole-burning was used to investigate the nature of the TBP absorption spectrum.…”

Section: Introductionmentioning

confidence: 99%

Quasi-line vibronic spectra of 2,3,12,13-tetramethyldibenzoporphine and their interpretation

Solovyov

Arabei

Гладков³

et al. 2003

J. Porphyrins Phthalocyanines

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The quasi-line fluorescence and fluorescence excitation spectra of 2,3,12,13-tetramethyldibenzoporphine have been obtained at 77 K in n-octane and analyzed. The normal-coordinate analysis of this molecule has been performed, and the spectra have been interpreted in detail. In the Soret band region the fluorescence excitation quasi-line spectra clearly reveal two 0-0 components. The problem of the nature of the Soret band of free-base porphyrins is discussed.

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“…Fluorescence from each of the states was observed in the emission if the degeneracy was lifted [11]. For example, dual fl uorescence from two closely spaced triplet levels of chlorophylls and pheophytins was recorded [12]. However, the manifestation of duality in all these instances depended on the solvent.…”

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confidence: 99%

Anisotropy of Dual Fluorescence of 2,3-Diazabicyclo[2.2.2]Oct-2-Ene and 1,4-Dimethyl-(2,3-Diazabicyclo[2.2.2]Oct-2-Ene)

2014

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Absorption, fl uorescence excitation, and fl uorescence spectra and the fl uorescence polarization as a function of emission wavelength were measured at 77 K for glassy EtOH solutions of 2,oct-2-ene). It was concluded from an analysis of the results that two excited electronic states were responsible for the emission of these compounds. The transition dipole moment vectors from the ground state into the excited ones were mutually perpendicular so that the corresponding spectra were shifted.Introduction. The azo-compound 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO) was studied previously as the jet-cooled vapor. The mirror symmetry of the absorption and fl uorescence spectra was broken by a diffuse long-wavelength band and also by splitting (by 0.55 cm -1 ) of the purely electronic and vibronic bands that was caused by tunneling [1]. This compound was interesting because its fl uorescence spectrum was broad, signifi cantly exceeding the width of the absorption spectrum, and practically independent of the solvent. The mechanism through which the broadening occurred is still unclear. Polarized absorption and fl uorescence spectra are used to observe multi-center emission and to resolve its components. Signifi cant results that were important for understanding the nature and basic features of the fl uorescence of complicated organic compounds were obtained [2,3].Polarized fl uorescence of DBO and 1,4-dimethyl-(2,3-diazabicyclo[2.2.2]oct-2-ene) (dimethyl-DBO) in glassy EtOH at 77 K were measured in the present work:

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Polarization spectra of metalloporphyrins

Cited by 9 publications

References 7 publications

Free base tetraazaporphine isolated in inert gas hosts: Matrix influence on its spectroscopic and photochemical properties

Free base tetraazaporphine isolated in inert gas hosts: Matrix influence on its spectroscopic and photochemical properties

Quasi-line vibronic spectra of 2,3,12,13-tetramethyldibenzoporphine and their interpretation

Anisotropy of Dual Fluorescence of 2,3-Diazabicyclo[2.2.2]Oct-2-Ene and 1,4-Dimethyl-(2,3-Diazabicyclo[2.2.2]Oct-2-Ene)

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