Phosphorus chemical shift tensors in dithiadiphosphetane disulfides determined by solid-state 31P nuclear magnetic resonance.

The phosphorus chemical shift tensors of two dithiadiphosphetane disulfides, 2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-di sulfide (1) and 2,4-bis(methylthio)-1,3-dithia-2,4-diphosphetane-2,4-disu lfi de (2), have been characterized by solid-state 31P nuclear magnetic resonance (NMR) measurements. The weak homonuclear dipolar interaction between the two 31P nuclei in each of these compounds has a significant influence on the 31P NMR line shapes of static powder samples. From the weak dipolar splittings it is possible to deduce the orientation of the phosphorus chemical shift tensor. In both compounds, the intermediate components of the phosphorus chemical shift tensors, delta 22, were found to be perpendicular to the plane defined by the two phosphorus atoms and the two terminal sulphur atoms in the molecule, S=P ... P=S. The smallest shift components, delta 33, were found to deviate approximately 14 degrees from the P=S bond direction.