Electron spin resonance formation kinetics

Thermal analyses of the sodium salts of several sulphuroxyacids, including some non-isothermal kinetic data, have been reported [813], Evidence for the formation of SOi radicals during such reactions has been obtained [348] by electron spin resonance measurements. 

Although Ce(IV) oxidation of carboxylic acids is slow and incomplete under similar reaction conditions , the rate is greatly enhanced on addition of perchloric acid. No kinetics were obtained but product analysis of the oxidations of -butyric, isobutyric, pivalic and acetic acids indicates an identical oxidative decarboxylation to take place. Photochemical decomposition of Ce(IV) carbo-xylates is highly efficient unity) and Cu(ll) diverts the course of reaction in the same way as in the thermal oxidation by Co(IIl). Direct spectroscopic evidence for the intermediate formation of alkyl radicals was obtained by Greatorex and Kemp ° who photoirradiated several Ce(IV) carboxylates in a degassed perchloric acid glass at 77 °K in the cavity of an electron spin resonance spectro-... 

Radiation techniques, application to the study of organic radicals, 12, 223 Radical addition reactions, gas-phase, directive effects in, 16, 51 Radicals, cation in solution, formation, properties and reactions of, 13, 155 Radicals, organic application of radiation techniques, 12,223 Radicals, organic cation, in solution kinetics and mechanisms of reaction of, 20, 55 Radicals, organic free, identification by electron spin resonance, 1,284 Radicals, short-lived organic, electron spin resonance studies of, 5, 53 Rates and mechanisms of solvolytic reactions, medium effects on, 14, 1 Reaction kinetics, polarography and, 5, 1... 

Bauer G (2000) Reactive oxygen and nitrogen species efficient, selective and interactive signals during intercellular induction of apoptosis. Anticancer Res 20 4115-4140 Beckwith AU, Davies AG, Davison IGE, Maccoll A, Mruzek MH (1989) The mechanisms of the rearrangements of allylic hydroperoxides 5a-hydroperoxy-3p-hydrocholest-6-ene and 7a-hydro-peroxy-3(1-hydroxycholest-5-ene. J Chem Soc Perkin Trans 2 815-824 Behar D, Czapski G, Rabani J, Dorfman LM, Schwarz HA (1970) The acid dissociation constant and decay kinetics of the perhydroxyl radical. J Phys Chem 74 3209-3213 Benjan EV, Font-Sanchis E, Scaiano JC (2001) Lactone-derived carbon-centered radicals formation and reactivity with oxygen. Org Lett 3 4059-4062 Bennett JE, Summers R (1974) Product studies of the mutual termination reactions of sec- alkylper-oxy radicals Evidence for non-cyclic termination. Can J Chem 52 1377-1379 Bennett JE, Brown DM, Mile B (1970) Studies by electron spin resonance of the reactions of alkyl-peroxy radicals, part 2. Equilibrium between alkylperoxy radicals and tetroxide molecules. Trans Faraday Soc 66 397-405... 

Wardman P, Dennis MF, Everett SA, Patel KB, Stratford MRL, Tracy M (2003) Radicals from one-electron reduction of nitro compounds, aromatic N-oxides and quinones the kinetic basis for hypoxia-selective, bioreductive drugs. Biochem Soc Symp 61 171-194 Warman JM, de Haas MP, Hummel A, van Lith D, VerberneJB, Loman H (1980) A pulse radiolysis conductivity study of frozen aqueous solutions of DNA. Int J Radiat Biol 38 459-459 Warman JM, de Haas MP, Rupprecht A (1996) DNA a molecular wire Chem Phys Lett 249 319-322 Warters RL, Lyons BW (1992) Variation in radiation-induced formation of DNA double-strand breaks as a function of chromatin structure. Radiat Res 130 309-318 Warters RL, Hofer KG, Harris CR, Smith JM (1977) Radionuclide toxicity in cultured mammalian cells Elucidation of the primary site of radiation damage. Curr Top Radiat Res Q 12 389-407 Weiland B, Huttermann J (1998) Free radicals from X-irradiated, dry and hydrated lyophilized DNA as studies by electron spin resonance spectroscopy analysis of spectral components between 77 K and room temperature. Int J Radiat Biol 74 341-358 Weinfeld M, Soderlind K-JM (1991) 32P-Postlabeling detection of radiation-induced DNA-damage identification and estimation of thymine glycols and phosphoglycolate termini. Biochemistry 30 1091-1097... 

Valinsky, J. E., Abeles, R. H., and Eee, J. A., 1974, Electron spin resonance studies on diol dehydrase. III. Rapid kinetic studies on the rate of formation of radicals in the reaction with propanediol, J. Am. Chem. Soc. 96 4709n4710. 

The side chain can also affect electronic events of the tricyclic ring system. Electron spin resonance experiments allowed Fenner S to suggest that the influence of the side chain of phenothiazine on the formation of free radicals showed a correlation between the redox activity of the phenothiazine nucleus and dynamic aspects of stereochemistry. For example, there was a difference in the formation of cationic free radicals between promazine and alimemazine. The latter has a branched side chain, and forms cationic free radicals only under irradiation. It differs from promazine in pharmacodynamic properties, reported s to result in considerably shifted ion exchange equilibria. A kinetic study of the oxidation of dopamine by dialkylaminoalkyl phenothiazine cationic free radicals showed that a strong correlation existed between side-chain structures and oxidation rates phenothiazine free radicals with two carbon side chains had faster rates than those with three carbon side diains, albeit both were very rapid at physiological pH. 

The dependence of the dissociation constant kj) and the recombination constants kjt in the reaction (a) on the optical polarization of the atoms A was predicted by Bernheim [65] and Kastler [225] and later demonstrated experimentally [7, 363]. The dependence can be understood from the obvious fact that only hydrogen-like atoms with opposite electronic spins may recombine and form a molecule A2(X1E+). Hence we have kR = kft(l — S2), where S is the degree of electron spin polarization of the atoms. A convenient indicator of dimer formation is provided by the kinetics of the laser-induced molecular fluorescence after switching on magnetic resonance which destroys the polarization of the atoms, as performed by Huber and Weber [201] for a Na — Na2 mixture. The se-... 

---