53544-99-3Relevant academic research and scientific papers
Fluoro spin adducts and their modes of formation
Eberson, Lennart,Persson, Ola
, p. 893 - 898 (2007/10/03)
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.
Acyl Nitroxides. Part 4. Estimation of OH Bond Dissociation Energies for N-t-Butylhydroxamic Acids
Jenkins, Terence C.,Perkins, M. John
, p. 717 - 720 (2007/10/02)
E.s.r. spectroscopy has been used to determine the equilibrium constants for the hydrogen exchange reactions between N-t-butylhydroxamic acids and the stable piperidine N-oxyl (1); since the O-H bond strength in (1)-H is known, this gives an estimate of the O-H bond strengths in the hydroxamic acids.These are found to be stronger than those in dialkyl nitroxides and increase with increasing electron demand in the acyl group.
