Thermodynamics of some long-chain biradicals studied by EPR spectroscopy

TLDR: In this article, four biradicals of differing chain lengths have been prepared by spin labeling the sulphhydryl groups of dithiothreitol, and temperature-dependent EPR spectra indicate that the dynamics of these Biradicals is associated with both fast and slow exchanges of conformations.

Abstract: Four biradicals of differing chain lengths have been prepared by spin-labelling the sulphhydryl groups of dithiothreitol. Temperature-dependent EPR spectra of these biradicals indicate that the dynamics of biradicals is associated with both fast and slow exchanges of conformations. The three-conformational model incorporating cage configuration is found to be more appropriate. Certain thermodynamic parameters of conformationalchanges have been calculated from the experimental EPR parameters, obtained by the use of simulation procedures developed recently.