Electron aqueous

Aqueous electron transfer reactions vanadium(V) as reductant compared to iron(II). D. R. Ros-seinsky, Chem. Rev., 1972, 72, 215-229 (116). 

Hostettler, J. D. (1984). Electrode reaction, aqueous electrons, and redox potentials in natural waters. Am. J. Sci. 284,734-759. 

Previous SECM studies have suggested that a Butler-Volmer type approximation could be used for the ITIES at low driving forces [83], For a system where an ET reaction occurs between an aqueous electron donor and an oxidant in the organic phase, the free energy barrier is given by... 

Joshi, AA Locke, BR Arce, P Finney, WC. Formation of hydroxyl radicals, hydrogen peroxide and aqueous electrons by pulsed streamer corona discharge in aqueous solution. Journal of Hazardous Materials, 1995 41,3-30. 

Vanadium(iv) Complexes.—Aqueous electron-transfer reactions involving V as a reductant have been reviewed. 

The aqueous electron will react rapidly with all four of the nucleobases. Reaction of the aqueous electron with deoxyribose or ribose phosphate is 2 orders of magnitude lower, so the dominant interaction is with the bases. 

Chemistry of Aqueous Electrons 12.2.1 Formation of Radical Species... 

Aqueous electron, e, is a powerful reducing reagent with an E°= 2.7 V. It reacts with many hazardous halogenated and nonhalogenated organic com-... 

Second-Order Rate Constants (M 1 s 1) of Selected Compounds for Reactivity with Aqueous Electrons... 

Falcone JM, Becker D, Sevilla MD, Swarts SG (2005) Products of the reaction of the dry and aqueous electron with hydrated DNA hydrogen and 5,6-dihydropyrimidines. Radiat Phys Chem 72 257-264... 

Sessler, J.L. et al. (2001) Probing the reactivity of the radiation sensitizer motexafin gadolinium (Xcytrin) and a series of lanthanide(III) analogues in the presence of both hydroxyl radicals and aqueous electrons, J. Porphyrins Phthalocyanines 5, 593-599. 

The reactions of the aqueous electron (e aq) with specific organic and inorganic compounds have been studied extensively [4-6]. The e aq is a powerful reducing agent, with a reduction potential of —2.77 V. The reactions of the e aq are single-electron transfer, the general form of which is ... 

As may be expected oxyanions of molecules known as antioxidants were also found to produce solvated electrons under irradiation. Phenolate anion in water leads to aqueous electron photoejection under 254 nm irradiation [62] and to benzosemiquinone through phenoxy radicals as shown by CIDNP arguments [63], In the case of / -naphtholate [64] the electron is photoejected from the unrelaxed singlet state [65, 66] with a low quantum yield (see Table 3) [67],... 

Figure 3. Schematic diagram of an apparatus for measuring transmembrane oxidation-reduction in a planar bilayer membrane. The mechanism described is simple carrier-mediated electron transport. D = aqueous electron donor A = aqueous electron acceptor ...

The ability of micelles to enhance photoionization yields of hydrophobic molecules was demonstrated in the early 1970s. Thus, the photoionization yields of pyrene [59], phenothiazine [60] and tetramethylbenzidine [61] cations increased when these molecules were encapsulated in anionic micelles. The effect was attributed to efficient escape of electrons from the geminate charge-separated species formed within the micelle, which is accelerated by the anionic interface. The negative micellar surface imposes an electrostatic barrier between the cations, which remain with the micelle, and the aqueous electron in the bulk water phase, thus increasing the lifetimes of the photoredox products. 

OH + e (aq) + n + HzO + H + H2O2 + H2 The first 14 water molecules per nucleotide in the hydration layer surrounding DNA have approximately the same mass as DNA [84] and, therefore, the same number of ionizations are expected to occur in the primary hydration layer as in the DNA strand. However, it is unknown how the water molecules in the primary hydration layer are affected by radiation. One possibility is that water cations and electrons are formed, which transfer their ionic character to the DNA strand (quasi-direct effects). Water cations can also transfer protons to neighboring water molecules resulting in hydroxyl radicals. The products formed in the hydration layer (hydroxyl radicals, hydrogen atoms or aqueous electrons) can subsequently react with DNA (indirect effects). Quasi-direct and indirect effects are expected to yield very different radicals. 

A hypothesis describing the source and sink of photolytically produced aqueous electrons is given in Figure 12,3c. As Table 12.3b shows, the steady-state concentration of e (aq) in a fresh water is relatively low (10 M). Reactions with O2 (to O ) constitute the major sink. Because the yield of solvated electrons in natural waters is so low, its reactions can be of only minor importance in producing photooxidants. 

Below pH 2 in N2 or Ar saturated solutions, nearly equal amounts ofthe OH radicals and H atoms are present. This is because aqueous electrons are converted to H by reacting with the hydroxonium ions ... 

Evidence for the activity of some radioprotectors as inhibitors of free radical processes has appeared, and the subject has been reviewed Involvement of MEA as well as of metal ionsf in free radical formation in proteins and bacteria has been observed. It was also found that cysteine and glutathione could accept electrons from irradiated proteins, whereas cystine and non-sulfur compounds did not Presence of metal ions, particularly cupric, had a protective effect for ribo-nuclease, presumably by intercepting electrons and preventing radical formation on the enzymer A protective effect of mucopolysaccharide polyanions and cysteine for trypsin and RHA, however, was not considered to be due to transfer of radiation energy to the protectors " Furthermore, substances known to react with H atoms or the aqueous electron did not protect hydrated E. coll cells from X-rays ... 

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