39058-86-1Relevant academic research and scientific papers
Fluoro spin adducts and their modes of formation
Eberson, Lennart,Persson, Ola
, p. 893 - 898 (1997)
The reactions of two fluorinating reagents, XeF2 and N-fluorodibenzenesulfonamide [(PhSO2)2N-F], with several spin traps have been investigated. In dichloromethane, the strong oxidant XeF2 cleanly gives fluoro spin adducts with N-tert-butyl-α-phenylnitrone (PBN) or 5,5-dimethyl-1-pyrroline 1-oxide (DMPO) according to a mechanism mediated by the radical cation of the spin trap. In both cases, further fluorination takes place with replacement of the a hydrogen by fluorine. The much weaker oxidant (PhSO2)2N-F reacts with PBN or DMPO in dichloromethane giving both the fluoro adduct and an adduct formally derived from an N-centred radical, assigned the structure of PhSO2N(F)-PBN? or (PhSO2)2N-DMPO?, respectively. This type of reaction proceeds by a version of the Forrester-Hepburn mechanism, in which an acid HA, in this case HF, initially adds to the nitrone function to give a hydroxylamine derivative which is oxidized by (PhSO2)N-F giving the fluoro spin adduct, a proton and the highly labile radical anion (PhSO2)2N-F?-. By decomposition of the latter to PhSO2(F)N- and PhSO2?, conditions are set up for propagation of the reaction by a new molecule of HA [now PhSO2(F)NH] and thus formation of the PhSO2(F)N spin adduct.
Spin trapping of fluoroalkyl radicals
Gille, Lars,Stoesser, Reinhard
, p. 191 - 194 (2007/10/02)
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
