Pulse radiolysis radical products

Both CO and C02 are reduced by eh. The immediate product of the first reaction is CO-, which reacts with water, giving OH and the formyl radical the latter has been identified by pulse radiolysis. The product of carbon dioxide reduction, C02-, is stable in the condensed phase with an absorption at 260 nm. It reacts with various organic radicals in addition reactions, giving carboxylates with rates that are competitive with ion-ion or radical-radical combination rates. 

Mieden OJ, von Sonntag C (1989) Peptide free-radicals the reactions of OH radicals with glycine anhydride and its methyl derivatives sarcosine and alanine anhydride. A pulse radiolysis and product study. Z Naturforsch 44b 959-974... 

Akhlaq MS, Murthy CP, Steenken S, von Sonntag C (1989) The reaction of a-hydroxyalkyl radicals and their anions with oxidized dithiothreitol. A pulse radiolysis and product analysis study. J Phys Chem 93 4331-4334... 

AravindakumarCT, Mohan FI.MudaliarM, RaoBSM, Mittal JP, Schuchmann MN, von Sonntag C (1994) Addition of eaq and FI atoms to hypoxanthine and inosineand the reactions of a-hydroxyalkyl radicals with purines. A pulse radiolysis and product study. Int J Radiat Biol 66 351-365... 

Walbiner M, Wu JQ, Fischer H (1995) Absolute rate constants for addition of benzyl (PF1CH2) and cumyl (PhCMe2) radicals to alkenes in solution. Helv Chim Acta 78 910-924 Wang D, Schuchmann H-P, von Sonntag C (1993) Phenylalanine its OH and SO -induced oxidation and decarboxylation. A pulse-radiolysis and product analysis study. Z Naturforsch 48b 761 -770... 

Nese C, Schuchmann MN, Steenken S, von Sonntag C (1995) Oxidation vs. fragmentation in radiosensitization. Reactions of a-alkoxyalkyl radicals with 4-nitrobenzonitrile and oxygen. A pulse radiolysis and product study. J Chem Soc Perkin Trans 2 1037-1044 Neta P, Huie RE, Mosseri S, Shastri LV, Mittal JP, Maruthamuthu P, Steenken S (1989) Rate constants for reduction of substituted methyl peroxyl radicals by ascorbate ions and N,N,N, N -tetrameth-yl-p-phenylenediamine. J Phys Chem 93 4099-4104 Neta P, Huie RE, Ross AB (1990) Rate constants for reactions of peroxyl radicals in fluid solutions. J Phys Chem Ref Data 19 413-513... 

Michaels HB, Rasburn EJ, Hunt JW (1976) Interaction of the radiosensitizer para-nitroacetophenone with radiation-induced radicals on nucleic acid components. Radiat Res 65 250-267 Mieden OJ, Schuchmann MN, von Sonntag C (1993) Peptide peroxyl radicals base-induced O2 elimination versus bimolecular decay. A pulse radiolysis and product study. J Phys Chem 97 3783-3790... 

Moorthy PN, Hayon E (1975) Free-radical intermediates produced from the one-electron reduction of purine, adenine and guanine derivatives in water. J Am Chem Soc 97 3345-3350 Mori M, Teshima S-l, Yoshimoto H, Fujita S-l, Taniguchi R, Hatta H, Nishimoto S-l (2001) OH Radical reaction of 5-substituted uracils pulse radiolysis and product studies of a common redox-ambivalent radical produced by elimination of the 5-substituents. J Phys Chem B 105 2070-2078 Morin B, Cadet J (1995) Chemical aspects of the benzophenone-photosensitized formation of two lysine - 2 -deoxyguanosine cross-links. J Am Chem Soc 117 12408-12415 Morita H, Kwiatkowski JS,TempczykA(1981) Electronic structures of uracil and its anions. Bull Chem Soc Jpn 54 1797-1801... 

C. Nese, M.N. Schuchmann, S. Steenken and C. von Sonntag, Oxidation vs. fragmentation in radiosensitization. Reactions of a-alkoxyalkyl radicals with 4-nitrobenzonitrile and oxygen. A pulse radiolysis and product analysis study, J. Chem. Soc., Perkin Trans. 2, (1995) 1037. 

Pulse radiolysis results (74) have led other workers to conclude that adsorbed OH radicals (surface trapped holes) are the principal oxidants, whereas free hydroxyl radicals probably play a minor role, if any. Because the OH radical reacts with HO2 at a diffusion controlled rate, the reverse reaction, that is desorption of OH to the solution, seems highly unlikely. The surface trapped hole, as defined by equation 18, accounts for most of the observations which had previously led to the suggestion of OH radical oxidation. The formation of H2O2 and the observations of hydroxylated intermediate products could all occur via... 

Elegant evidence that free electrons can be transferred from an organic donor to a diazonium ion was found by Becker et al. (1975, 1977a see also Becker, 1978). These authors observed that diazonium salts quench the fluorescence of pyrene (and other arenes) at a rate k = 2.5 x 1010 m-1 s-1. The pyrene radical cation and the aryldiazenyl radical would appear to be the likely products of electron transfer. However, pyrene is a weak nucleophile the concentration of its covalent product with the diazonium ion is estimated to lie below 0.019o at equilibrium. If electron transfer were to proceed via this proposed intermediate present in such a low concentration, then the measured rate constant could not be so large. Nevertheless, dynamic fluorescence quenching in the excited state of the electron donor-acceptor complex preferred at equilibrium would fit the facts. Evidence supporting a diffusion-controlled electron transfer (k = 1.8 x 1010 to 2.5 X 1010 s-1) was provided by pulse radiolysis. 

The product CO3 radical can react with a variety of inorganic ions including the carbonato complex of Pu(V). Thus, in a pulse radiolysis experiment, Pu(VI) in 0.05 M Na2C03, He saturated, there are the parallel reactions (17) and (18)... 

In marked contrast there exists a volumnous literature on pulse radiolysis studies of nitric acid solutions (9). The NO3 radical has been identified as a major product although the mechanism of formation is still a matter of debate. While a number of reactions of this radical have been reported (10) there has evidently not been any pulse radiolysis studies of reactions with Pu ions. 

By pulse radiolysis of nitrous oxide-saturated aqueous solutions of ferricyanide (2 X 10 " M) and various alcohols (0.1 M), Adams and Willson " were able to obtain absolute rate coefficients for the ferricyanide oxidation of the radicals derived from the alcohols by attack of the solvent irradiation product, OH-. 

Kemp and coworkers employed the pulse radiolysis technique to study the radiolysis of liquid dimethyl sulfoxide (DMSO) with several amines as solutes [triphenylamine, and N, A, A, N -tetramethyl-p-phenylenediamine (TMPD)]. The radiolysis led to the formation of transient, intense absorptions closely resembling those of the corresponding amine radical cations. Pulse radiolysis studies determine only the product Ge, where G is the radiolytic yield and e is the molar absorption. Michaelis and coworkers measured e for TMPD as 1.19 X 10 m s and from this a G value of 1.7 is obtained for TMPD in DMSO. The insensitivity of the yield to the addition of electron scavenger (N2O) and excited triplet state scavenger (naphthalene) proved that this absorption spectrum belonged to the cation. 

In a pulse radiolysis study of solutions of CdS of different particle size, the rate of reaction of the OH radical with the colloidal particles was studied as well as the absorption spectrum of the products The hydroxyl radical reacts on its first encounter... 

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