SE-77 SHIELDING TENSORS OF DIPHENYL DISELENIDE, COMPARISON OF THE RESULTS FROM CP MAS NMR-SPECTROSCOPY AND IGLO CALCULATIONS/

The cross-polarization/magic-angle-spinning (CP/MAS) (77)SeNMR experim ent of Ph-Se-Se-Ph affords two signal series with isotropic chemical s hifts at delta(iso) = 425 and 350. IGLO calculations allow to assign t he Se-77 signals and to predict the orientation of the shielding tenso rs. The different chemical shifts can be explained by different torsio n angles Se-Se-C-ipso-C-ortho which produce different beta effects of the phenyl rings upon the respective next but one selenium atom.