Spin adduct formation from the spontaneous reaction between spin traps and weak electron acceptors, as exemplified by trichloroacetonitrile. An acid promoted version of the Forrester–Hepburn addition–oxidation mechanism

Abstract

The thermal reaction between N-tert-butyl-α-phenylnitrone (PBN) and trichloroacetonitrile is promoted by acids HA, giving spin adducts A–PBN˙ and CCl₂CN–PBN˙, presumably via addition of HA to the nitrone with formation of a hydroxylamine and oxidation of the latter by trichloroacetonitrile (the Forrester–Hepburn mechanism).