Electron spin resonance spectrum of a new anthraquinone aglycone (Nodosin).

Abstract

The Electron Spin Resonance study of 1,3,5,8-tetrahydroxy 2,7-dimethyl anthraquinone known as Nodosin has been carried out at room temperature and at X-band. The compound gives a norrow ESR line. The measurements of lineshape, linewidth and g-value have been made. A theoretical computation of dipolar width as well as narrowing due to exchange has been carried out with the help of KUBO and TOMITA theory and finally a value for J, the exchange coupling parameter has been estimated. On the basis of these measurements Nodosin has been proposed to adopt an intermediate structure.