Density functional studies of free radicals: accurate geometry and hyperfine coupling prediction for semiquinone anions

Density functional calculations utilising the B3LYP functional are used to calculate geometries together with 1H, 13C and 17O isotropic coupling constants for p-benzosemiquinone, durosemiquinone and plastosemiquinone anion radicals. Comparison of results obtained with experimental determinations indicates excellent agreement between theory and experiment.