The diethyl dithiophosphate complex of tetraphenylantimony(V) and its solvated form, [Sb(C6H5)4{S2P(OC2H5)2}] • 1/2 C6H6: Synthesis, crystal structure, and 13C, 31P CP/MAS NMR study. an example of monodentate coordination of dithio ligands

The O,O'-diethyl dithiophosphate complex of tetraphenylantimony(V) [Sb(C6H5)(4){S2P(OC2H5)(2)}] (I) and its benzene-solvated form I center dot 1/2C(6)H(6) (II) were synthesized and studied by high-resolution solid-state C-13 and P-31 NMR (MAS NMR). The diethyl dithiophosphate (Dtph) groups in I and II were quantitatively characterized by the P-31 chemical shift anisotropy (delta(aniso)), the asymmetry parameter (eta), and the principal values of chemical shift tensors (delta (xx) , delta (yy) , delta (zz) ). The calculation of the anisotropy parameters included construction of chi(2) statistic diagrams from full P-31 MAS NMR spectra. In both complexes, the Dtph groups were found to have mainly axially symmetric P-31 chemical shift tensors (for delta (zz) < delta (xx) a parts per thousand delta (yy) ) with similar anisotropy parameters (delta(aniso) and eta), which is due to their identical S-monodentate function. According to X-ray diffraction data, II has a trigonal bipyramidal (TBP) molecular structure with Smonodentate coordination of Dtph in the TBP axial position and outer-sphere position of the benzene molecule. The desorption of the outer-sphere benzene solvent molecules from structure II, which was noted in MAS NMR experiment, passes through the formation of three intermediate solvated forms with benzene content n < 1/2.