Correlation of31P chemical shift parameters to molecular structures of hexacoordinate organophosphorus compounds in the solid state

31 P principal elements of chemical shift tensors δii for a series of hexacoordinate organophosphorus compounds have been obtained from spinning sideband intensities employing the MASNMR program based on a graphical method of Berger and Herzfeld. It was found that anisotropy parameters Δδ and span Ω reflect the distortion of the molecular structure from the ideal octahedral geometry. The asymmetry parameter η and skew κ suggest that the phosphorus shielding depends not only on the local bonding, but also on the octahedral structure as a whole. Comparison of isotropic chemical shifts in solution and in solids revealed that in both phases the molecular structures are not changed. Moreover, this work shows that for PVI moieties with unknown X-ray structure, crucial information regarding the geometry can be obtained from solid-state NMR data and a molecular modelling approach.