Studie �ber postmortale Abbauvorg�nge

Schmidt, Otto; Lorke, Dietrich; Forster, B.

doi:10.1007/bf00664890

Cited by 14 publications

(8 citation statements)

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“…Quantitative analysis showed two-to threefold greater decrease of A2E in D 2 O than in H 2 O. Due to the longer lifetime of singlet oxygen in D 2 O (68 ms) [19] compared to H 2 O (4.2 ms), [19] the epoxidation and the decrease in A2E levels should be faster in D 2 O than in H 2 O. Indeed, a strong isotope effect was observed.…”

mentioning

confidence: 99%

Formation of a Nonaoxirane from A2E, a Lipofuscin Fluorophore related to Macular Degeneration, and Evidence of Singlet Oxygen Involvement

et al. 2002

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Neun Epoxidringe entstehen nacheinander, wenn A2E mit blauem Licht in Gegenwart von Sauerstoff bestrahlt wird [Gl. (1)]. Mechanistisch gesehen erzeugt A2E Singulettsauerstoff und reagiert mit diesem zu den Polyoxiranen. Das Verständnis der Reaktion von A2E mit Sauerstoff ist wichtig, weil blaues Licht die Apoptose von A2E‐beladenen Zellen des retinalen Pigmentepithels auslöst, die typisch für die altersabhängige Makuladegeneration ist.

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mentioning

confidence: 99%

Formation of a Nonaoxirane from A2E, a Lipofuscin Fluorophore related to Macular Degeneration, and Evidence of Singlet Oxygen Involvement

et al. 2002

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“…Analysis shows the kinetics to be of second order, with a first half life of 4 minutes. This time constant is considerably higher than the lifetime Reaction time/min 4…”

Section: Methoxyphenyl Diazosulphonatesmentioning

confidence: 89%

“…Phenyl diazosulphonates have first been synthesized by Schmidt and Lutz in 1869 [4]. This group of compounds is characterized by high molar absorption coefficients (s on the order of 5000 I mol-1 em -I in the UV spectral range), and is stable up to temperatures above 150°C.…”

Section: Introductionmentioning

confidence: 99%

“…5Kinetics of the formation of 4-methoxyphenyl diazosulphonate from the corresponding diazonium salt and sulphite (concentrations 10-3 M, each, see text). a) Spectra (bottom to top) were recorded at increasing times(4,9,14, 19,24,29,34,39,44, and 49 minutes) after mixing. Formation of the diazosulphonate is recognized by the appearance of a band in the 400 -440 nm range.…”

mentioning

confidence: 99%

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Pulsed Ultraviolet Laser Photolysis of Substituted Phenyl Diazosulphonates at 248 nm

Nomayo

Wokaun

1995

Ber Bunsenges Phys Chem

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The photochemical decomposition of aqueous phenyl diazosulphonate solutions by KrF excimer laser pulses at 248 nm is investigated. The present study complements earlier investigations (Franzke et al. 1991, 1992) of the photochemistry of this class of compounds induced by irradiation at 308 nm (XeCl excimer laser), and in the 370–390 nm wavelength range (dye laser pulses). From the comparison, conclusions with regard to the wavelength dependent photolysis pathway are drawn. Phenyl diazosulphonates carrying methoxy‐ or ester‐type substituents at the aromatic ring are observed to decompose in a two‐step‐reaction in aqueous solution: Photolysis proceeds via the phenyl diazonium ion as an intermediate, to yield the corresponding phenol as a product. In contrast, the photolysis of 3‐vinyl‐phenyl diazosulphonate in aqueous solution at 248 nm results in a complex reaction involving via more than one intermediate. UV spectra recorded during photolysis show that products characterized by an absorption maximum at 272 nm are formed; these spectra are identical with those of final products from 308 nm photolysis, which are identified as 3‐hydroxyethyl‐phenols. – The photolysis pathway of 4‐hydroxy‐phenyl‐diazosulphonate is found to proceed via the diazoquinone, instead of a diazonium ion. As a consequence of the high energy of 248 nm photons, the mentioned substituted phenols are not the final products of the photochemical reaction. These molecules are further decomposed by absorbing 248 nm photons; the quantum efficiency of these secondary photochemical reactions is lower by one to two orders of magnitude, as compared to the primary photolysis of the parent compounds.

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“…Photodynamic therapy for cancer mostly involves reaction of guanine bases of mutated DNA with 1 O 2 [1][2][3][4]. The lifetime of 1 O 2 varies over a wide range in going from one medium to another [5]. It shows that 1 O 2 interacts quite differently with different types of molecules.…”

Section: Introduction E Xcitation Energy Transfer From a Dye Moleculementioning

confidence: 99%

Binding of ³O₂ and ¹O₂ to dyes used in photodynamic therapy in gas phase and aqueous media

Kushwaha

Mishra

2006

Int J of Quantum Chemistry

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Density functional theory (DFT) was employed at the B3LYP/6-31ϩG* level to study complexes of 1 O 2 and 3 O 2 with the dye molecules proflavine, methylene blue, and acridine orange, which are useful in photodynamic therapy. It was found that the most stable complex between 1 O 2 and proflavine are formed when 1 O 2 is located above the central ring, while the most stable complex between 1 O 2 and methylene blue is formed when 1 O 2 is located above the molecular plane, but not above any of the rings, near the sulfur atom.1 O 2 can make a stable complex with acridine orange, as it is located above the outer ring of the dye. The binding energies of the complexes of 1 O 2 with all three dyes are enhanced considerably in going from gas phase to aqueous media. The complexes of 3 O 2 with the dyes will be unstable in all cases, while those of 1 O 2 with the same will be quite stable and will not be dissociated due to thermal fluctuations at room temperature. In the complexes of 1 O 2 and 3 O 2 with the dyes, charge transfer occurs from the dyes to the O 2 moiety, the amount of charge transfer being much more to 1 O 2 than to 3 O 2 in each case.

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Studie �ber postmortale Abbauvorg�nge

Cited by 14 publications

References 0 publications

Formation of a Nonaoxirane from A2E, a Lipofuscin Fluorophore related to Macular Degeneration, and Evidence of Singlet Oxygen Involvement

Formation of a Nonaoxirane from A2E, a Lipofuscin Fluorophore related to Macular Degeneration, and Evidence of Singlet Oxygen Involvement

Pulsed Ultraviolet Laser Photolysis of Substituted Phenyl Diazosulphonates at 248 nm

Binding of ³O₂ and ¹O₂ to dyes used in photodynamic therapy in gas phase and aqueous media

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Studie �ber postmortale Abbauvorg�nge

Cited by 14 publications

References 0 publications

Formation of a Nonaoxirane from A2E, a Lipofuscin Fluorophore related to Macular Degeneration, and Evidence of Singlet Oxygen Involvement

Formation of a Nonaoxirane from A2E, a Lipofuscin Fluorophore related to Macular Degeneration, and Evidence of Singlet Oxygen Involvement

Pulsed Ultraviolet Laser Photolysis of Substituted Phenyl Diazosulphonates at 248 nm

Binding of 3O2 and 1O2 to dyes used in photodynamic therapy in gas phase and aqueous media

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Binding of ³O₂ and ¹O₂ to dyes used in photodynamic therapy in gas phase and aqueous media