Synthesis, structure, and 13C and 31P CP/MAS NMR of the tetraphenylantimony(V) di-iso-propyl phosphorodithioate complex [Sb(C6H5)4{S2P(O-iso-C3H7)2}] and its solvated form [Sb(C6H5)4{S2P(O-iso-C3H7)2}] · 1/2C6H6: An example of the monodentate coordination of dithio ligands

Abstract

The crystalline tetraphenylantimony(V) O,O′-di-iso-propyl phosphorodithioate complex [Sb(C6H5)4{S2P(O-i-C3H7)2}](I) and its solvated form [Sb(C6H5)4{S2P(O-i-C3H7)2}] · 1/2C6H6(II) were synthesized. Solid compounds I and II were studied by MAS NMR (13C, 31P). The 31P NMR chemical shift anisotropy 31P δaniso = (δzz − δiso) and asymmetry parameter η = (δyy − δxx)/(δzz − δiso) were calculated using χ2 plots constructed on the basis of the 31P MAS NMR data. The O,O′-di-iso-propyl phosphorodithioate ligands in both complexes are characterized by predominantly the axially symmetric 31P chemical shift tensor (for the case δzz < δxx ≈ δyy) with close values of anisotropy parameters (δaniso and η), which reflects their identical S-monodentate structural function. X-ray crystallography showed that II has a trigonal-bipyramidal molecular structure with the uncommon monodentate coordination of the Dtph ligands through an S atom in an axial position of the trigonal bipyramid and the benzene molecule in the outer sphere.