Exchange effects on the 1H and 31P nmr spectra of cyclodiphosph(III)azane selenides and tellurides

Oxidation of the isomeric cyclodiphosph(III)azanes, (Me₂ NPNBu-t)₂, by selenium and by tellurium gives both isomeric monoselenides but only one monotelluride. Variable temperature ¹H and ³¹P NMR studies provide evidence for restricted rotation about the exocyclic PN bonds, and in the telluride, of exchange of tellurium between the phosphorus atoms.