E.S.R. study of the conformational kinetics of a biradical

Intramolecular motion in the biradical N,N'-bis(2,2,6,6-tetramethyl-1-oxyl-4-piperidinyl)ethylenediamine which contains two ionizable amine groups has been studied by E.S.R. spectroscopy. The line-shapes of the spectra as a function of pH and temperature were analysed by density matrix methods to give values for rates and free-energies of activation.