Long-range nuclear spin–spin coupling between selenium-77 and phosphorus-31 in biphosphorus compounds

The coupling constants ⁿJ(⁷⁷Se³¹P), n = 1–4, have been measured in the proton-decoupled ³¹P NMR spectra of a range of diphosphorus selenides and diselenides. ³¹P–{¹H, ³¹P} and ³¹P–{¹H, ⁷⁷Se} triple resonance experiments have been used to establish the signs of the coupling constants, and it is found that both the magnitudes and signs depend upon the stereochemical relationship of the coupled nuclei.