Fluorescence quenching and ESR spectroscopy of metallic porphyrins in the presence of an electron acceptor

Wróbel, Danuta; Łukasiewicz, Jȩdrzej; Manikowski, H.

doi:10.1016/s0143-7208(03)00032-9

Cited by 24 publications

(9 citation statements)

References 20 publications

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“…Accordingly, beside the distortion, as a steric effect, also the coordination of the metal center, as a potential electronic effect, is necessary for the complete quenching of emission. Nevertheless, Wrobel and coworkers [112] observed fluorescence in the DMSO solution of Pb II TPP, but on the basis of Fig. 3 in their publication, its spectrum was the same as that of the free-base porphyrin.…”

Section: Singlet-1 Fluorescencementioning

confidence: 96%

Application of the electronic spectra of porphyrins for analytical purposes: The effects of metal ions and structural distortions

Valicsek

Horváth

2013

Microchemical Journal

114

118

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We investigated the UV-Vis absorption, singlet-1 and singlet-2 fluorescence, as well as the formation of several metalloporphyrins from equilibrial and kinetic aspects in aqueous solution. Among these complexes were numerous typical out-of-plane and several in-plane metalloporphyrins, and between the two categories, a few border-line cases. On the basis of our results, we have complemented the categorization introduced by Barnes and Dorough for the metalloporphyrins. According to our observations, also in metalloporphyrins, the distortion, i.e., the planarity or nonplanarity of the macrocycle, is basically responsible for the spectral characteristics, while the electronic structure of metal center is a secondary factor, with a considerable importance mainly in the in-plane complexes. The type of complexes can be spectrophotometrically determined on the basis of their UV-Vis absorption and fluorescence spectra. Beside the spectral and photophysical effects of metalation, also those of the structural distortions were studied, which can originate also from metalation, protonation or overcrowded peripheral substitution of the free-base porphyrins, as well as from the axial ligation of metalloporphyrins. Our observation may be useful for different spectrophotometric analytical detection and determination methods, e.g. size-selective metal detection using free-base porphyrins (or other ringed chelate ligands), as well as the determination of Lewis bases as potential axial ligands, using metalloporphyrins.

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Section: Singlet-1 Fluorescencementioning

confidence: 96%

Application of the electronic spectra of porphyrins for analytical purposes: The effects of metal ions and structural distortions

Valicsek

Horváth

2013

Microchemical Journal

114

118

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“…In one of our paper [26] we have evidently shown very marked porphyrin fluorescence quenching in the presence of the covalently linked fullerene C 60 due to electron transfer. On the basis of the fluorescence quenching data describing the processes in 10 À9 s in porphyrins [17,26] and the ESR results presented in this paper we can draw some conclusions on the process occurring in the time scale between ns and ls. If electron transfer from the porphyrins to the fullerene occurs and no fullerene radicals in our LESR experiment are observed it may imply very prompt relaxation of the unpaired electron on the C 60 moiety in the range of about 10 À9 -10 À10 s due to charge recombination.…”

Section: Resultsmentioning

confidence: 70%

“…Porphyrins form a wide-spread class of naturally occurring molecules and commonly used dyes. The UV-Vis absorption spectrum of the highly conjugated porphyrin macrocycle exhibits an intense feature at about 400 nm (the Soret band) followed by several weaker absorptions (Q bands) at longer wavelengths (from 450 to 750 nm), which are changed by the peripheral substituents on the porphyrin ring and insertion of metal ions into the centre of the ring [4,[11][12][13][14][15][16][17][18]. The extensively conjugated p-systems of porphyrins increase their electron-donor abilities, so that they are suitable for efficient electron transfer in the ground and excited states [4,12,13].…”

Section: Introductionmentioning

confidence: 99%

Charge transfer in fullerene – porphyrin-derived dyads studied with light-induced electron spin resonance

et al. 2007

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“…The values of the generated photopotential for both dyes in the PEC are similar to each other, indicating that the peripheral groups do not essentially influence the generated photosignal. On the basis of our independent ESR studies it was shown [21] that the Β-electron system in the macrocyclic dyes is responsible for the observed photoresponse. The addition of the dopa melanin markedly changes the photoelectric properties of both dyes as seen in Fig.…”

Section: Resultsmentioning

confidence: 97%

Photovoltage generation and fluorescence of charged tetraphenylporphyrins with dopa melanin

Hanyż

Wróbel²

2003

Cryst. Res. Technol.

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Positively charged tetra(4-N,N,N,N-trimethylanilinium) porphyrin (TAP) and negatively charged tetrakis(4-sulphonatophenyl) porphyrin (TPPS 4 ) and their mixtures with dopa melanin in polyvinyl alcohol have been investigated. On the basis of the absorption and fluorescence spectra it has been established the formation of TAP-dopa melanin complex which fluorescence is quenched whereas TPPS 4 fluorescence behaviour is only slightly changed in the presence of dopa melanin. Photovoltaic effects and photocurrent generation in a photoelectrochemical cell consisting of a layer dye solutions sandwiched between the semiconducting and gold electrodes have been investigated. The dependence of photovoltage signal on excitation wavelength (photovoltage action spectrum), kinetics of photocurrent rise and decay in the second time scale have been presented. Electric parameters of the photoelectrochemical cell (conductivity and capacitance) with porphyrin dyes, dopa melanin and their mixtures in the dark and upon illumination have been estimated. It was shown that all investigated dyes are able to generate photosignal but the values of photocurrent generated depend on the dye used in the experiment and the presence or absence of dopa melanin.

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Fluorescence quenching and ESR spectroscopy of metallic porphyrins in the presence of an electron acceptor

Cited by 24 publications

References 20 publications

Application of the electronic spectra of porphyrins for analytical purposes: The effects of metal ions and structural distortions

Application of the electronic spectra of porphyrins for analytical purposes: The effects of metal ions and structural distortions

Charge transfer in fullerene – porphyrin-derived dyads studied with light-induced electron spin resonance

Photovoltage generation and fluorescence of charged tetraphenylporphyrins with dopa melanin

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