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Knyukshto, V. N.; Zenkevich, É. I.; Sagun, E. I.; Шульга, А. М.; Bachilo, Sergei M.

doi:10.1023/a:1009439730497

Cited by 48 publications

(96 citation statements)

References 25 publications

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“…fl fl fl fl (8) where Δn possesses values from 0 to 1. One can see that the slope of the function Φ fl = f(Δn) is defined as the difference Φ fl (T2) − Φ fl (T1).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Unraveling the Fluorescence Features of Individual Corrole NH Tautomers

et al. 2012

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ABSTRACT:The fluorescence spectra of 10-(4,6-dichloropyrimidin-5-yl)-5,15-dimesitylcorrole have been studied in the temperature range from 4.2 to 332 K. For the first time, the individual fluorescence profiles of the two corrole NH tautomers have been assigned over the whole temperature range. The pronounced temperature dependence of the fluorescence spectra of the meso-pyrimidinylcorrole under study was found to originate from switching between the fluorescence emissions of the two tautomers due to a reduced NH tautomerization rate with decreasing temperature. As a result, the long wavelength tautomer dominates the total emission spectrum at room temperature, whereas at low temperatures, the majority of the emission comes from the short wavelength tautomer. Energy level diagrams (involving the two NH tautomers) explaining the excitation energy deactivation channels in the meso-pyrimidinylcorrole at room temperature and below are presented. A significant H/D isotope effect on the NH tautomerization rate has been observed, resulting in an enhanced contribution of the short wavelength tautomer to the total fluorescence spectrum at the expense of that of the long wavelength tautomer. Substantially different fluorescence quantum yields have been determined for the individual NH tautomers, leading to a pronounced temperature dependence of the overall fluorescence quantum yield. The obtained results allow the unambiguous statement that the two NH tautomers of corroles coexist in fluid and solid solutions in a wide range of temperatures, with the proportion depending on the corrole substitution pattern. Moreover, this study shows that the (future) interpretation of the fluorescence properties of mesopyrimidinylcorroles and all other corrole materials should be done (more) carefully, taking into account the coexistence of NH tautomers with individual spectral signatures.

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“…fl fl fl fl (8) where Δn possesses values from 0 to 1. One can see that the slope of the function Φ fl = f(Δn) is defined as the difference Φ fl (T2) − Φ fl (T1).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Unraveling the Fluorescence Features of Individual Corrole NH Tautomers

et al. 2012

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“…2А -(where A -denotes the acid residue). [14,23] For the DP form of Н 2 ОEP the decrease in Φ fl was measured as compared to the value found for the FB species (Φ fl = 0.09 [52] ). [23] Thus, a slight Φ fl decrease was found for the cases where the protonation has been done with acids which did not contain heavy atoms (acetic, formic or sulfuric acid): Φ fl = 0.07-0.085.…”

Section: Photophysical Properties Of Mono-and Diprotonated Porphyrinsmentioning

confidence: 99%

“…[14,21,24] The Φ fl value for the DP form of Н 2 TPP lies in the range 0.08-0.106, [17,18,24] whereas Φ fl value for the FB species is 0.09-0.11. [24,52] The shortening of the fluorescence lifetime upon protonation indicates that both radiative and radiationless deactivation rates increase to the same extent. [37] Two-fold build-up of the fluorescence has been observed for the DP form of 5,10,15,20-tetra-2-methylphenylporphyrin as compared to the DP form of Н 2 TPP.…”

Section: Photophysical Properties Of Mono-and Diprotonated Porphyrinsmentioning

confidence: 99%

Influence of Macrocycle Protonation on the Photophysical Properties of Porphyrins

Kruk¹,

Старухин²,

Maes³

2011

MHC

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“…The long-wavelength band corresponds to the two doubly degenerate purely electronic transitions whilst shorter -to the transitions to the vibrational sublevels of these states [1]. In the case of metalloporphyrins, the double degeneracy of electronic transitions can be removed at low temperatures due to Jahn-Teller instability or a few others factors and the energy gap between the electronic states becomes higher than 100 cm -1 [2][3][4]. In this context, it seems quite interesting to investigate the splitting effects of long-wavelength bands in the absorption spectra of metallophthalocyanines containing ligands coordinated to the central metal atom and thus located out of the macrocyclic plane and compare the data with results gained for symmetrical metallophthalocyanines and metalloporphyrins.…”

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confidence: 99%

“…The splitting of long-wavelength bands in the absorption spectra of metallophtalocyanines containing out-of-plane ligands is considered to be caused by the transition of macrocyclic core to the nonplanar "dome" conformation [4,6] and additional loss by macrocycle a fourfold symmetry.…”

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confidence: 99%

Spectral manifestation of substitution of out-of-plane ligands in metallophtalocyanines

et al. 2016

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Abstract. In our study, we demonstrate the splitting effect of longwavelength bands in absorption spectra (excitation of fluorescence) of the series of Zn(II), Ti(IV), Zr(IV) and Hf(IV) phthalocyanines at low temperatures. The effect has been explained by the shift of metal ion out of the plane of phthalocyanine macrocycle, the transformation of macrocycle to nonplanar "dome" conformation and additional loss the high symmetry of macrocycle.The molecules of metalloporphyrins and metallophthalocyanines belong to the high symmetry group D4h and exhibit only two wide absorption bands in the visible spectrum range at ambient temperature. The long-wavelength band corresponds to the two doubly degenerate purely electronic transitions whilst shorter -to the transitions to the vibrational sublevels of these states [1]. In the case of metalloporphyrins, the double degeneracy of electronic transitions can be removed at low temperatures due to Jahn-Teller instability or a few others factors and the energy gap between the electronic states becomes higher than 100 cm -1 [2][3][4]. In this context, it seems quite interesting to investigate the splitting effects of long-wavelength bands in the absorption spectra of metallophthalocyanines containing ligands coordinated to the central metal atom and thus located out of the macrocyclic plane and compare the data with results gained for symmetrical metallophthalocyanines and metalloporphyrins. As a reference in our studies, symmetrical metallocomplex -Zn(II) phthalocyanine was selected.The phthalocyanines containing Zn(II), Ti(IV), Zr(IV) and Hf(IV) ions were studied in the current work. The structures of Zn tetra-tretbutylphthalocyanine ( t-Bu PcZn) and complex of Zr or Hf phthalocyanine with two out-ofplane dibenzoylmethanate ligands (PcMDbm2) are presented on Fig. 1. The set of absorption and fluorescence excitation experiments of phthalocyanine metallocomplexes have been carried out at low temperatures (ranging from 9 to 77 K) in 2-methyltetrahydrofuran forming an optical transparent rigid glassy matrix at these conditions.Upon the above-mentioned In the case of t-Bu PcZn the splitting of the long-wavelength band at 77 K was not so obvious. While, for compounds with out-of-plane ligands the

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Cited by 48 publications

References 25 publications

Unraveling the Fluorescence Features of Individual Corrole NH Tautomers

Unraveling the Fluorescence Features of Individual Corrole NH Tautomers

Influence of Macrocycle Protonation on the Photophysical Properties of Porphyrins

Spectral manifestation of substitution of out-of-plane ligands in metallophtalocyanines

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