Aminoxyl group

Aminoxyl radicals are chemical species containing the R2Nā€“Oā€¢ functional group. They are also known as nitroxyl radicals and nitroxides, however IUPAC discourages the use of these terms, as they erroneously suggest the presence of a nitro group.[1] They are radicals and are structurally related to hydroxylamines and N-oxoammonium salts, with which they can interconvert via a series of redox steps.

Sterically hindered aminoxyls such TEMPO and TEMPOL and are persistent (stable) radicals and find use in a range of oxoammonium-catalyzed oxidations. They are also present as transitory species various polymer stabilizers such as hindered amine light stabilizers and some p-phenylenediamine based antiozonants.[2] Nitroxide-mediated radical polymerization uses aminoxyl radicals to mediate the reaction and TEMPO-type compounds are also used as polymerization inhibitors. Various other reagents, such as N-Hydroxyphthalimide can also be converted into aminoxyl radicals as part of their chemistry.

See also

  • Nitrone - structurally related, an N-oxide of an imine

References

  1. IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version:  (2006ā€“) "aminoxyl radicals". doi:10.1351/goldbook.A00285
  2. Cataldo, Franco (January 2018). "Early stages of p-phenylenediamine antiozonants reaction with ozone: Radical cation and nitroxyl radical formation". Polymer Degradation and Stability. 147: 132ā€“141. doi:10.1016/j.polymdegradstab.2017.11.020.
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