Singlet oxygen formation and photostability of meso-tetraarylporphyrin derivatives and their copper complexes

Cavaleiro, José A. S.; Görner, Helmut; Lacerda, Paula S. S.; MacDonald, John; Mark, Gertraud; Neves, Maria G. P. M. S.; Nohr, Ronald S.; Schuchmann, Heinz‐Peter; Sonntag, Clemens von; Tomé, Augusto C.

doi:10.1016/s1010-6030(01)00540-8

Cited by 53 publications

(20 citation statements)

References 53 publications

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“…The fact that the Φ Δ value determined for C 6 H 3 F 2 P (0.72) is apparently greater than the experimental Φ T (0.64) value is probably because of the large uncertainty in the latter value, as the triplet–singlet difference spectrum for this compound shows a very sharp peak in the region of the analytical wavelength, and it was not possible to find any other suitable region for study. The only data available in the literature for comparison of singlet oxygen yields are Φ Δ = 0.84 for C 6 F 2 H 3 P, obtained using time‐resolved photoacoustic calorimetry (PAC) (16) and Φ Δ = 0.8 (CH 2 Cl 2 ) and 0.6 (toluene) for C 6 F 5 P, obtained by time‐resolved phosphorescence (61). The value we obtain for C 6 F 5 P in benzene is intermediate between the values reported for this compound in dichloromethane and toluene.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Spectra and Photophysics of some Free Base Tetrafluoroalkyl and Tetrafluoroaryl Porphyrins with Potential Applications in Imaging¶

Grancho

Pereira

Miguel

et al. 2007

Photochemistry and Photobiology

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The synthesis, characterization and photophysical properties of two perfluoroalkyl (5,10,15,20‐tetrakis‐[trifluoromethyl]‐ and [heptafluoropropyl]‐porphyrin) and two perfluoroaryl (5,10,15,20‐tetrakis‐[2,6‐difluorophenyl]‐ and [pentafluorophenyl]‐porphyrin) are described, with reference to their potential in both photodynamic therapy (PDT) and in vivo imaging by fluorescence and 19F nuclear magnetic resonance spectroscopy. Absorption and fluorescence spectra, fluorescence lifetimes and triplet–singlet difference spectra are reported. Triplet yields have been obtained by flash photolysis and pulse radiolysis, whereas yields of sensitized singlet oxygen formation have been determined by time‐resolved phosphorimetry. All four compounds show high yields of triplet formation and singlet oxygen sensitization. The spectral properties, stability and attractive solubility characteristics of the perfluoroalkyl derivatives make them particularly suitable candidates for future study for applications in PDT.

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Section: Resultsmentioning

confidence: 99%

Synthesis, Spectra and Photophysics of some Free Base Tetrafluoroalkyl and Tetrafluoroaryl Porphyrins with Potential Applications in Imaging¶

Grancho

Pereira

Miguel

et al. 2007

Photochemistry and Photobiology

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“…Photodegradation of the macrocycle in H 2 Por has usually been attributed to oxygen-mediated reactions that may be prompted due to absorption of photonic energy by both the porphyrin substrate and molecular oxygen. Since excited porphyrins may sensitize O 2 species to give rise to the formation of singlet molecular oxygen ( 1 D g ) along with some other radicals, it is frequently referred to as the principal reason for the photo-bleaching of porphyrins [39][40][41][42]. Hence, it is important to assess the stability range for the most promising porphyrin systems, including their protonated forms.…”

Section: Coomentioning

confidence: 99%

meso-Aryl-substituted free-base porphyrins: formation, structure and photostability of diprotonated species

et al. 2015

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Susceptibility to interact with trifluoroacetic acid (TFA) of selected freebase porphyrins, including a novel lipophilic 3-n-pentadecyl(phenoxy)-ethoxyphenyl-substituted porphyrin, and photostability of their diprotonated compounds was explored in benzene and N,N-dimethylformamide (DMF). Results have been discussed in terms of the commonly applied pK a -based procedure and confronted with a simple approach derived from experimentally-determined correlations reflecting the porphyrins affinity for TFA. Density functional theory (DFT) has proved the porphyrin moiety creates stable diprotonated species involving two TFA molecules, in which the fluorine atoms effectively contribute to the overall interaction of the acid with the porphyrin macrocycle. The relevance of the mesosubstituent and ambient medium to the reactivity and photostability of diverse porphyrin derivatives was emphasized and referred to structural features of the investigated diprotonated porphyrins.

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“…Skin photosensitization was found to be minimal when drug-injected mice were illuminated in a solar simulator (Selman et al 1993). As expected, the photodynamic ability of this complex required the presence of molecular oxygen in order to generate reactive species upon light activation , Cavaleiro et al 2001. Sometimes, the efficacy of one-photon PDT is limited by hypoxia, which can prevent the production of the cytotoxic singlet oxygen species, leading to tumor resistance for PDT.…”

Section: Photodynamic Therapy and Singlet Oxygen Productionmentioning

confidence: 78%

Photochemical Transformations Involving Porphyrins and Phthalocyanines

Sergeeva¹,

Senge²

2012

CRC Handbook of Organic Photochemistry and Photobiology, Third Edition - Two Volume Set

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Singlet oxygen formation and photostability of meso-tetraarylporphyrin derivatives and their copper complexes

Cited by 53 publications

References 53 publications

Synthesis, Spectra and Photophysics of some Free Base Tetrafluoroalkyl and Tetrafluoroaryl Porphyrins with Potential Applications in Imaging¶

Synthesis, Spectra and Photophysics of some Free Base Tetrafluoroalkyl and Tetrafluoroaryl Porphyrins with Potential Applications in Imaging¶

meso-Aryl-substituted free-base porphyrins: formation, structure and photostability of diprotonated species

Photochemical Transformations Involving Porphyrins and Phthalocyanines

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