Primary Products of Liquid Water Photolysis at 1236, 1470 and 1849 Å

Getoff, N.; Schenck, Günther O.

doi:10.1111/j.1751-1097.1968.tb05859.x

Cited by 100 publications

(50 citation statements)

References 25 publications

(14 reference statements)

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“…The solutions were irradiated with a monochromatic UV(C)-light of 254 nm (4.85 eV/hm) in a special, double-wall 4π-irradiation apparatus connected with a thermostat [16].…”

Section: Methodsmentioning

confidence: 99%

The 4-hydroxyestrone: Electron emission, formation of secondary metabolites and mechanisms of carcinogenesis

Getoff

Gerschpacher

Hartmann

et al. 2010

Journal of Photochemistry and Photobiology B: Biology

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Abstract4-Hydroxyestrone (4-OHE 1 ), a typical cancer-inducing metabolite, originating from 17β-estradiol (17β-E2), was chosen as a model for the studies. The aim was to get a deeper insight in the mechanisms of its ability to initiate cancer. It was found, that 4-OHE 1 can eject electrons , when excited in the singlet state by monochromatic UV-light (γ = 254 nm) in polar media (water:ethanol = 40:60 vol.%). The quantum yield , determined for various 4-OHE 1 concentrations, is found to be as high as that previously observed for 17β-E2. It decreases with increasing substrate concentration, but it is enhanced at higher temperature. The ability of 4-OHE 1 to eject as well as to consume and to transfer electrons to other biological systems, classifies it as an electron mediator, similar to 17β-E2.The 4-OHE 1 transients resulting of the electron emission process are leading to the formation of secondary metabolites. Surprisingly, it was established that the secondary metabolites possess likewise the ability to eject as well as to consume electrons. Hence, they behave similar like 17β-E2. However, the structure of the secondary formed metabolites, which determinates their biological properties and carcinogenity, depends on the nature of the available reaction partners involved in their formation. A probable reaction mechanism explaining the subject matter is discussed.

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“…The solutions were irradiated with a monochromatic UV(C)-light of 254 nm (4.85 eV/hm) in a special, double-wall 4π-irradiation apparatus connected with a thermostat [16].…”

Section: Methodsmentioning

confidence: 99%

The 4-hydroxyestrone: Electron emission, formation of secondary metabolites and mechanisms of carcinogenesis

Getoff

Gerschpacher

Hartmann

et al. 2010

Journal of Photochemistry and Photobiology B: Biology

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“…was considered, but 0 experiments using sodium formate (which is a good hydroxyl radical scavenger (14)) showed no effect on radical decay rates .…”

Section: Pa Below For Further Comment)mentioning

confidence: 99%

Flash photolysis of flavins. IV. Some properties of the lumiflavin triplet state

Vaish

Tollin

1970

J Bioenerg Biomembr

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“…Details of fluores--LO00 cence measurements (2.7) as well as of steady-state irradiations at 254 and 229 nm (I I), actinometry at these wavelengths (I I, 14, 15), and the design of irradiation vessels (16) have been de-…”

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confidence: 99%

The role of the molecular environment for the primary photoprocesses of phenol in solution

Zechner¹,

Köhler²,

Grabner³

et al. 1980

Can. J. Chem.

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Can. J. Chem. 58,2006 (1980. Quantum yields of fluorescence as well as of solvated electron and H atom formation have been measured for phenol in several pure solvents and mixtures of varyingpolarity. The influence of excitation energy has been studied by excitation ofphenol in the first and second excited singlet states. The solvent dependences of fluorescence and photoejection parameters are strongly correlated. The results are interpreted in terms of specific solute-solvent interactions, in particular H-bonded structures.J. ZECHNER, G. KOHLER, G. G R A B N E~ et N. GETOFF. Can. J. Chem. 58,2006Chem. 58, (1980. Introduction the static dielectric constant (12) or Kosower's Solvent effects on photophysical properties of micropolarity parameter Z (6, 13)-These investimolecules are well known from studies of spectral gations showed that there is no simple relationship energy shifts between gas phase and solution. between solvent and fluorescence behaviour in the Many of the effects observed could be explained by case of the systems studied; the decrease of QF at a general theory of electrostatic interactions (1). higher excitation energies is related to the static However, the influence of solute-solvent interac-dielectric constant in a non-linear way (12). he tions on excited state decay processes and primary behaviour of Q F in different classes of solvents photochemical reactions is less well understood.(hydrocarbons, polar organic solvents, water) is various studies carried out during the last reflected in a different dependence on Z within each years have demonstrated, simple aromatic molethese (I3)-cules such as phenols, anilines, indoles, andThe aim of the present study was to obtain more aromatic amino acids share the interesting photo-information about solvent effects on primary physical property of having a fluorescence quan-~h o~o~r o c e s s e s f~o m S I and& states ofphenol. To yield (Q,) which is not independent of the this effect, the influence of excitation energy on the energy of excitation (2-5). It has been early recogquantum yield as as On nized that this effect is strongly influenced by the photoejection and H atom formation by OH bond solvent environment: the dependence of e F o n ex-rupture has been investigated in pure ~o l a r and citation energy is pronounced in hydrocarbon sol-apolar solvents and in solvent mixtures. Particular vents, small in polar organic solvents, but notable has been paid the possible of again in water (2, 6). A correlation between the Specific S~lUte-S~l~ent interactions On these proeffect on QFand the hydrogen bonding capability of cesses. the solvent was suggested in the case of phenol (7).Experimental Section Furthermore, a connection with excitation

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Primary Products of Liquid Water Photolysis at 1236, 1470 and 1849 Å

Cited by 100 publications

References 25 publications

The 4-hydroxyestrone: Electron emission, formation of secondary metabolites and mechanisms of carcinogenesis

The 4-hydroxyestrone: Electron emission, formation of secondary metabolites and mechanisms of carcinogenesis

Flash photolysis of flavins. IV. Some properties of the lumiflavin triplet state

The role of the molecular environment for the primary photoprocesses of phenol in solution

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