An electron spin resonance study of quinone di-imide radical anions

Abstract

The e.s.r. spectra of the NN′-bisphenylsulphonyl-p-benzoquinone di-imine radical anion, its 2,3- and 2,5-di-chloro-substituted analogues, and the NN′-dicyano-p-benzoquinone di-imine radical anion are reported. The observation of two sets of equivalent protons in the bisphenylsulphonyl-p-benzoquinone di-imine and the NN′-di-cyano-derivative radical anions is interpreted on the basis of slow rotational isomerism of the para-substituents.