Photophysics of cationic 5,10,15,20-tetrakis-(4-N-methylpyridyl) porphyrin bound to DNA, [poly(dA-dT)]2 and [poly(dG-dC)]2: on a possible charge transfer process between guanine and porphyrin in its excited singlet state

Chirvony, Vladimir S.; Galievsky, Victor A.; Kruk, N. N.; Джагаров, Б. М.; Turpin, Pierre‐Yves

doi:10.1016/s1011-1344(97)00043-2

Cited by 85 publications

(57 citation statements)

References 54 publications

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“…However, in our experimental results, we did not observe any significant dependence of st on f. The changes in the TMPyP absorption and fluorescence spectra due to variations of the solvent polarity could be associated with charge transfer (CT) between the porphyrin core and lateral groups, which contributes to the formation of their lowest absorption maximum [32][33][34]. However, when CT transitions do occur at the change of the environment polarity, the absorption and fluorescence spectra appear significantly shifted [35] while in our experiments we have observed just a weak effect of solvent polarity on the TMPyP spectra.…”

Section: Tablementioning

confidence: 56%

“…The larger Stokes shift in water, compared to that of organic solvents, can be associated to a higher f in water. It can also be associated to the solvent polarity effect on the CT transition, as proposed in the literature [32][33][34]. However, the increase of environment polarity generally induces a red shift of the CT absorption band [35].…”

Section: Tablementioning

confidence: 82%

“…The interaction of the TMPyP ring with surrounding water molecules can be responsible for the appearance of new vibrational levels and the subsequent increase of rates of the radiationless excited-state relaxation. According to [33,34], the broadening of the TMPyP fluorescence spectrum in water, as well as the reduction of S 1 state lifetime, result from intramolecular charge-transfer. However, we believe that this broadening can be employed as an indirect argument in favor of the increase of numbers of vibrational levels in TMPyP excited-state.…”

Section: Tablementioning

confidence: 99%

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Effects of environment on the photophysical characteristics of mesotetrakis methylpyridiniumyl porphyrin (TMPyP)

Gonçalves

Franzen

Corrêa

et al. 2011

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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Section: Tablementioning

confidence: 56%

Section: Tablementioning

confidence: 82%

Section: Tablementioning

confidence: 99%

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Effects of environment on the photophysical characteristics of mesotetrakis methylpyridiniumyl porphyrin (TMPyP)

Gonçalves

Franzen

Corrêa

et al. 2011

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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“…The fluorescence decay kinetics were recorded on a PRA-3000 pulsed fluorimeter. The fluorescence quantum yield of HTMPyP -was measured by the relative method in [8]; as the reference compound, we used H 2 TMPyP (Φ fl = 0.044 [7,9]). …”

mentioning

confidence: 99%

“…We know that on going from the free base to the metal complex, the fluorescence quantum yield Φ fl decreases by a factor of 2-5, and the probability of fluorescence k fl increases by a factor of ≈2 [23]. Despite the fact that due to the presence of an efficient intramolecular quenching channel due to charge transfer from the macrocycle to the pyridyl substituents [20], the fluorescence quantum yield of the free base H 2 TMPyP is initially low (Φ fl = 0.044 [9]), the fluorescence quantum yield of the Zn complex decreases by almost a factor of two (Φ fl = 0.025 [10,13]), while the probability of fluorescence increases. Considering the monodeprotonated form HTMPyP -as on a par with the metal complexes, we note that the probability of fluorescence also follows the indicated pattern for the metal complexes (see Table 2).…”

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confidence: 99%

Fluorescent properties and symmetry of the monodeprotonated form of 5,10,15,20-tetrakis-(4-N-methylpyridyl)-porphyrin

Kruk

2006

J Appl Spectrosc

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The spectral and kinetic properties of the monodeprotonated form of the cationic 5, 10,15,porphyrin (H 2 TMPyP) in solution are studied. The experimental results obtained are interpreted based on the four-orbital Gouterman model. It is established that the monodeprotonated form HTMPyP -can be assigned to the D4h symmetry point group, and has spectral and photophysical characteristics similar to the characteristics of the fluorescent metal complexes of H 2 TMPyP with relatively low electronegativity of the chelated metal ion. It is hypothesized that formation of the monodeprotonated form HTMPyP -is accompanied by a decrease in the oxidation potential of the porphyrin molecule.Introduction. Porphyrin molecules are amphoteric compounds having properties of both bases and acids [1]. The basic properties of porphyrins are exhibited in protonation of the nitrogen atoms of the pyrrolenine rings when reacted with acids, and formation of monoprotonated and diprotonated forms. The acidic properties of porphyrins result in dissociation of the pyrrole protons during formation of metal complexes. The complete scheme for possible acidbase equilibria for the studied 5,10,15,20-tetrakis-(4-N-methylpyridyl)-porphyrin (H 2 TMPyP) is shown in Fig. 1. While the monoprotonated and especially the doubly protonated form of different porphyrins have been rather intensively studied, the monodeprotonated and doubly deprotonated molecules have been practically ignored by researchers. It has been assumed that these forms are extremely unstable, and they are difficult to detect experimentally [1, 2]. We know of only two experimental papers in which monodeprotonated forms have been obtained for two compounds: porphin (H 2 P) and H 2 TMPyP [3,4], and one theoretical paper where a quantum chemical study was carried out for the monodeprotonated form of porphin, HP - [5]. Fluorescence has been detected for the monodeprotonated form of porphin HP -[3], but the problem of studying the channels and rates for deactivation of the electronic excitation energy in such proton-deficient porphyrin systems has not been tackled.It proves to be impossible to obtain the isolated monodeprotonated form in organic solvents, due to the strong interaction between the macrocycle and the conjugate counterion of the base [3]. In aqueous solutions, association of ions is observed only at very high concentrations, since water (as a solvent with high polarity) can decrease the strong electrostatic interaction between unlike charged ions to such an extent that they might dissociate into free solvated ions [6]. So in the case of aqueous solutions, we can study just the role of dissociation of one of the pyrrole protons in formation of the electronic absorption spectra and the channels for deactivation of the electronic excitation energy, without additional effects that might be due to the conjugate counterion. These considerations are the reason for selection of the H 2 TMPyP molecule, which has the most pronounced acidic properties among the water-soluble tetrapyrrole co...

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Binding of the cationic 5-coordinate Zn(II)-5,10,15,20-tetrakis(4-N-methylpyridyl)porphyrin to DNA and model polynucleotides: Ionic-strength dependent intercalation in [poly(dG-dC)]2

et al. 1999

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Photophysics of cationic 5,10,15,20-tetrakis-(4-N-methylpyridyl) porphyrin bound to DNA, [poly(dA-dT)]2 and [poly(dG-dC)]2: on a possible charge transfer process between guanine and porphyrin in its excited singlet state

Cited by 85 publications

References 54 publications

Effects of environment on the photophysical characteristics of mesotetrakis methylpyridiniumyl porphyrin (TMPyP)

Effects of environment on the photophysical characteristics of mesotetrakis methylpyridiniumyl porphyrin (TMPyP)

Fluorescent properties and symmetry of the monodeprotonated form of 5,10,15,20-tetrakis-(4-N-methylpyridyl)-porphyrin

Binding of the cationic 5-coordinate Zn(II)-5,10,15,20-tetrakis(4-N-methylpyridyl)porphyrin to DNA and model polynucleotides: Ionic-strength dependent intercalation in [poly(dG-dC)]2

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