Platinum(II) complexes of the tridentate thioether ligands RS(CH2)(3)S(CH2)(3)SR (R=Et, iPr, Ph). Structures of [PtCl(iPrS(CH2)(3)S(CH2)(3)SiPr)][BF4], [PtI(PhS(CH2)(3)S(CH2)(2)SPh)][BF4], and [Pt(PPh(3))(iPrS(CH2)(3)S(CH2)(3)SiPr)][BF4](2)center dot CH2Cl2

The tridentate thioether ligands RS(CH2)(3)S(CH2)(3)SR (L(1), R = Et; L(2), R = iPr, L(3), R = Ph) were synthesized by nucleophilic addition of thiolate, SR(-), to the ditosylate TsO(CH2)(3)S(CH2)(3)OTs. The complexes [PtX(L(n))][BF4] were prepared by displacement of 1,5-COD from [PtX(x)(1,5-COD)](X = Cl, I) in the presence of one equivalent of AgBF4 and one equivalent of thioether ligand. [PtCl(L(2))][BF4] crystallized in the monoclinic space group P2(1)/c with a = 10.409(6), b = 14.180(4), c = 13.726(8) Angstrom, beta = 104.49(4)degrees, V = 1961(2) Angstrom 3, and Z = 4. The structure refined to R = 5.62% and R(w) = 6.86% for 2121 reflections with F-0(2) > 3 sigma(F-0(2)). [PtI(L(3))][BF4] crystallized in the monoclinic space group P2(1)/n with a = 13.415(4), b = 12.350(5), c = 14.316(5) Angstrom, beta = 107.48(3)degrees, V = 2262(1) Angstrom(3), and Z = 4. The structure refined to R = 4.85% and R(w) = 6.33% for 2168 reflections with F-0(2) > 3 sigma(F-0(2)). In both compounds, the thioether ligand acts as a tridentate chelator occupying three of the four sites of the square-planar Pt(II) complex. Variable temperature C-13{H-1} NMR verified that there are three possible stereoisomers for these complexes resulting from inversion at sulphur: meso-A, meso-B, and racemic. Thermodynamic parameters were calculated for the interconversion among isomers of [PtCl(L(2))][BF4] by a full line-shape analysis. Removal of chloride ligand from [PtCl(L(2))][BF4] with Ag+ in the presence of PPh(3) yielded the phosphine adduct [Pt(PPh(3))(L(2))][BF4](2), which crystallized in the triclinic space group P (1) over bar with a = 13.266(3), b = 11.315(2), c = 13.970(2) Angstrom, alpha = 106.04(2)degrees, beta = 84.95(2)degrees, gamma = 86.56(2)degrees, V = 1999.7(7) Angstrom(3), and Z = 2. The structure refined to R = 4.22% and R(w) = 5.38% for 4493 reflections with F-0(2) > 3 sigma(F-0(2)). Unlike the two halide complex structures, which crystallized in the meso-B form, [Pt(PPh(3))(L(2))][BF4](2) crystallized in the racemic form.