- Oxidative cleavage of CH3 and CF3 radicals from BOXAM nickel complexes
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Oxidation of the nickel complexes [(BOXAM)Ni(R)] (HBOXAM = bis((4-isopropyl-4,5-dihydrooxazol-2-yl)phenyl)amine) with R = CF3, CH3, Cl leads to the corresponding radical cationic complexes, which rapidly undergo homolytic Ni-R bond s
- Klein, Axel,Vicic, David A.,Biewer, Christian,Kieltsch, Iris,Stirnat, Kathrin,Hamacher, Claudia
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- Single electron transfer (SET) reaction studies. A possible new role for nitrone spin trap
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A new role for nitrone (PBN:N-tert. Butyl α-phenyl nitrone) spin-trap in single electron transfer (SET) reactions is proposed.
- Khan,Bhattacharjee, Suchandra,Chandra, Harish,Symons, Martyn C.R.
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- Spin trapping of fluoroalkyl radicals
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The formation of fluoroalkyl radicals in liquid chlorofluorocarbons (CF2Cl-CFCl2, CFCl3, CFCl2-CH3, CHF2-CF2-CF2Cl, CF3-CFH-CF3 and CCl4) has been investigated by means of the spin trapping technique and ESR spectroscopy.It is shown that the primary fluoroalkyl radicals which were generated in these compounds by ionising radiation are preferably formed by bond cleavage at carbon atoms attached to one fluorine atom.Besides the liberation of chlorine atoms in chlorine-containing compounds, in CHF2-CF2-CF2Cl and CF3-CFH-CF3 fluorine atoms were also detected.By comparison of radicals formed from γ-irradiated CF2Cl-CFCl2 (CFC-113) and from CF2Cl-CFClI or CF2I-CFCl2 by zinc reduction, it was demonstrated that in CFC-113 both .CF2-CFCl2 and .CFCl-CF2Cl radicals are formed, whereas in iodine-containing homologues the formation of one species is favoured. - Keywords: Spin trapping; Fluoroalkyl radicals; ESR spectroscopy; γ-Irradiation; Zinc reduction; Phenyl-tert-butylnitrone
- Gille, Lars,Stoesser, Reinhard
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- USE OF SPIN TRAPS IN THE STUDY OF SILYL RADICALS IN THE GAS PHASE
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The aim of this study was to probe the utility of the spin-trapping tecnique for the identification and estimation of radicals derived from organosilicon compounds in the gas phase.The methods of generation comprised electric discharge and mercury-senzitized photolysis; the traps were Me3C-NO and PhCN=N(O)CMe3.After establishing that the procedures were satisfactory, using toluene and n-hexane as radical sources, a range of monosilanes was studied.Several systems gave reasonable yields of spin-trap radicals.For example, SiMe4 gave H2C.SiMe3 adducts, Me3SiH gave H2C.Si(H)Me3 and Me3Si. adducts and PhSiH3 gave PhSiH2 adducts.Certain chlorosilanes gave chlorine atom adducts using electric-discharge generation, but only very weak signals from unknown radical derivatives using the photolytic method.In many other cases, such as Me2SiH2 and MeSiH3, we were unable to detect any radical products despite extensive attempts under a wide range of conditions.We conclude that the technique is quite satisfactory for the detection of carbon-centred radicals, but is less reliable for the study of silyl radicals.In a few cases, we also used 2,6-di-t-butylquinone as a trap, but the results were less satisfactory than with the nitrone trap.
- Chandra, Harish,Davidson, Iain M. T.,Symons, Martyn C. R.
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- Spin trapping azidyl (N3.), cyanatyl (OCN.), cyanyl (.CN) radicals, and chlorine atom (Cl.)
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Azidyl, cyanatyl, and cyanyl radicals and chlorine atoms have been detected by spin trapping using α-phenyl-N-tert-butyl nitrone (PBN) in the monoelectronic electrooxidations of azide, cyanate, cyanide, and chlorine.Azidyl and cyanatyl radicals were also detected with PBN in the persulfate oxidations of azide and cyanate.Azidyl radicals could be detected in the reaction of azide with hydroxyl radicals in the presence of PBN.
- Janzen, Edward G.,Stronks, Henry J.,Nutter, Dale E.,Davis, Edward R.,Blount, Henry N.,et al.
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p. 1596 - 1598
(2007/10/02)
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