Über Galvinole und Galvinoxyle, III. EPR-Spektroskopie an regellos orientierten Bis-Galvinoxyl-Biradikalen in der Glasmatrix / On Galvinols and Galvinoxyls, III. EPR Study of Zero Field Splitting in Randomly Oriented Galvinoxyl Biradicals

ESR powder spectra of several differently bridged bis-galvinoxyl biradicals have been recorded. The spectra can be interpreted in terms of a weak electron-electron dipolar coupling between the unpaired spins of randomly oriented triplet molecules. Using MO-theory and a point charge model for atomic orbitals a detailed structural analysis is performed on the basis of quantum mechanical calculations. Taking into account the twist angles between the various aryl rings the experimental data can be explained satisfactorily.