31P double-quantum solid-state NMR study of phosphoroorganic compounds with (O)P-O-P-(O), (S)P-O-P(S) and (S)P-S-P(O) unit

In this work we have tested applicability of the commonly used double quantum recoupling sequence POST-C7 to study of 31P-31P geometrical constraints for phosphoroorganic model compounds with different chemical shift anisotropy (CSA) and distinct molecular dynamics in the crystal lattice. Our results clearly show that even with large CSA, POST-C7 gives good efficiency of 31P double-quantum excitations. Moreover, large amplitude molecular motion only slightly disturb 31P build-up curve. χ2 error analysis is used for verification of values and orientations of chemical shift tensors (CST) parameters employed for simulation of POST-C7 buildup curves.