Synthesis, solution and magic angle spinning tin-119 nuclear magnetic resonance studies and crystal structures of dithioether complexes of tin(IV) halides

The compounds SnX(4) reacted with 1 molar equivalent of dithioether, L-L, in dry CHCl3 solution to give the six-co-ordinate species [SnX(4)(L-L)] [X = Cl, L-L = MeS(CH2)(n)SMe, o-C6H4(SMe)(2) or PhS(CH2)(n)SPh (n = 2 or 3); X = Br, L-L = MeS(CH2)(n)SMe or o-C6H4(SMe)(2)] in high yield as white or pale yellow powdered solids. Using SnBr4 and PhS(CH2)(n)SPH or SnI4 with MeS(CH2)(n)SME did not produce isolable products, although solution Sn-119-{H-1} NMR spectroscopy provided evidence for their existence at low temperatures. X-Ray structural studies on [SnCl4{MeS(CH2)(2)SMe}], [SnCl4{MeS(CH2)(3)SMe}], [SnCl4{o-C6H4(SMe)(2)}], [SnCl4{PhS(CH2)(3)SPh}] and [SnBr4{MeS(CH2)(3)SMe}] confirmed an S(2)X(4) donor set with the dithioether acting as a bidentate chelate. Variable-temperature solution H-1 and Sn-119-{H-1} NMR spectroscopic studies showed that the complexes are extremely labile and ligand dissociation and pyramidal inversion are fast except at low temperatures. Magic angle spinning Sn-119 NMR data for [SnCl4(L-L)] are reported. The crystal structure of cis-[SnI4{MeS(O)(CH2)(3)SMe}(2)], obtained as decomposition product from the SnI4-MeS(CH2)(3)SMe reaction, shows monodentate sulfoxide (O) co-ordination.