Electron spin resonance and electron nuclear double resonance study of diastereomeric nitroxyl radicals produced by spin trapping

Electron spin resonance and electron nuclear double resonance spectra of nitroxyl radicals having two asymmetric carbons on one side of the nitroxyl function were observed. The radicals were produced by the abstraction of hydrogen by photoexcited benzophenone from amines, ethers, and alcohols followed by spin trapping with phenyl-N-t-butyInitrone. The difference in esr parameters of diastereomers depends on the functional group attached to the asymmetric carbon. The nature of the intramolecular interaction which brings about this difference is discussed in detail.