31P CP MAS NMR studies of bis(organothiophosphoryl) disulfides. Correlation of chemical shift tensors and shielding parameters to molecular structure

The principal elements of the 31P chemical shift tensors δii for a series of bis(organothiophosphoryl) disulfides have been calculated by employing the graphical method of Berger and Herzfeld from spinning sideband intensities. The linear relationship between the SP–S angle and anisotropy and asymmetry parameters has been shown. The orientation of the principal components δii with respect to the molecular frame was postulated. It has been suggested that the δ22 component is oriented along the P–S bond, whereas δ11 is oriented approximately along the direction bisecting the S–PS angle. Furthermore, the 31P CP MAS NMR spectra provide information about the number of magnetically and crystallographically non-equivalent phosphorus centres.