Inverted spin trapping. Part III. Further studies on the chemical and photochemical oxidation of spin traps in the presence of nucleophiles
- 1 January 1994
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 2
- No. 2,p. 171-176
- https://doi.org/10.1039/p29940000171
Abstract
Inverted spin trapping, denoting the reaction between the radical cation of a spin trap (ST˙+) and a nucleophile (Nu–), has been further explored with respect to the photochemical generation of ST˙+ and the use of 5,5-dimethyl-1-pyrroline 1-oxide (DMPO) and 3,3,5,5-tetramethyl-1-pyrroline 1-oxide (TMPO) as ST. It is shown that photoexcitation of N-benzylidene-tert-butylamine N-oxide (PBN) in the presence of a weak electron acceptor, tetrabutylammonium 12-tungstocobaltate(III), and a nucleophile gives the corresponding spin adducts, PBN–Nu˙, most likely via the intermediate radical cation, PBN˙+. This species could also be generated by sensitized photoxidation and made to react with Nu–. The cyclic N-oxides DMPO and TMPO are more difficult to oxidize than PBN(by 0.2–0.3 V), They both engage in inverted spin trapping, using both thermal and photochemical oxidation, but in a more restricted way than for PBN.Keywords
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