title: Donor-Free Alkali Metal Thiolates: Synthesis and Structure of Dimeric, Trimeric, and Tetrameric Complexes with Sterically Encumbered Terphenyl Substituents.
abstract: The synthesis and characterization of the tetrameric lithium thiolate (LiSC(6)H(2)-2,4,6-Ph(3))(4).C(7)H(8) (1), the trimeric lithium thiolate (LiSC(6)H(3)-2,6-Mes(2))(3).C(6)H(14)()()(2) (Mes = 2,4,6-Me(3)C(6)H(2)), the thiol HSC(6)H(3)-2,6-Trip(2) (3) (Trip = 2,4,6-i-Pr(3)C(6)H(2)), and the complete alkali metal series of dimeric thiolates (MSC(6)H(3)-2,6-Trip(2))(2) (M = Li (4, 5), Na (6), K (7), Rb (8), Cs (9)) are described. The compounds were characterized by (1)H, (7)Li, and (13)C NMR and IR spectroscopy and by X-ray crystallography. The compounds 1 and 2 crystallize as four- and three-rung ladder framework structures. The compounds 4-9 crystallize as dimers with M(2)S(2) cores. In addition, the metal ions interact with the ortho aryl groups to varying degrees in all the structures. The extent of these interactions appears to be determined mainly by ionic sizes and geometric factors. The coordination geometry of the thiolato sulfurs also varies from pyramidal in 1, 2, 4, 5, and 6 and one planar and one slightly pyramidal sulfur geometry in 7 to both sulfurs being planar coordinated in 8 and 9. Crystal data at 130 K are as follows: (LiSC(6)H(2)-2,4,6-Ph(3))(4).C(7)H(8) (1), a = 15.961(2) Å, b = 16.243(3) Å, c = 17.114(3) Å, alpha = 89.375(14) degrees, beta = 85.334(14) degrees, gamma = 63.343(12) degrees, V = 3950(1) Å(3), space group P&onemacr;, Z = 2, R(1) = 0.082; (LiSC(6)H(3)-2,6-Mes(2))(3).C(6)H(14)()()(2), a = 14.554(4) Å, b = 14.010(4) Å, c = 32.832(8) Å, beta = 95.20(2) degrees, V = 6667(2) Å(3), space group P2(1)/n, Z = 4, R(1) = 0.089; HSC(6)H(3)-2,6-Trip(2) (3), a = 8.180(2) Å, b = 25.437(5) Å, c = 15.752(3) Å, V = 3278(1) Å(3), space group Pnma, Z = 4, R(1) = 0.045; (LiC(6)H(3)-2,6-Trip(2))(2) (4), a = 12.652(2) Å, b = 14.218(1) Å, c = 18.713(2) Å, alpha = 83.56(1) degrees, beta = 84.36(1) degrees, gamma = 73.82(1) degrees, V = 3205(1) Å(3), space group P&onemacr;, Z = 2, R(1) = 0.055; (LiC(6)H(3)-2,6-Trip(2))(2).C(7)H(8) (5), a = 15.383(3) Å, b = 14.381(2) Å, c = 16.524(2) Å, beta = 111.10(1), V = 3410.3(9) Å(3), space group P2(1)/n, Z = 2, R(1) = 0.086; (NaSC(6)H(3)-2,6-Trip(2))(2).0.5C(7)H(8) (6), a = 13.952(2) Å, b = 20.267(2) Å, c = 24.475(3) Å, beta = 98.673(9) degrees, V = 6842(1) Å(3), space group P2(1)/n, Z = 4, R(1) = 0.068; (KSC(6)H(3)-2,6-Trip(2))(2).C(7)H(8) (7), a = 13.683(4) Å, b = 15.071(4) Å, c = 17.824(5) Å, alpha = 82.73(2), beta = 86.09(2), gamma = 88.46(2), V = 3637(2) Å(3), space group P&onemacr;, Z = 2, R(1) = 0.072; (RbSC(6)H(3)-2,6-Trip(2))(2).C(7)H(8) (8), a = 19.710(3) Å, b = 20.892(3) Å, c = 18.755(2) Å, beta = 106.900(9) degrees, V = 7389(2) Å(3), space group P2(1)/n, Z = 4, R(1) = 0.069; (CsSC(6)H(3)-2,6-Trip(2))(2) (9), a = 13.109(3) Å, b = 15.941(3) Å, c = 17.748(4) Å, alpha = 101.65(2) degrees, beta = 100.76(2) degrees, gamma = 104.25(2) degrees, V = 3410(1) Å(3), space group P&onemacr;, Z = 2, R(1) = 0.048.
authors.affiliation: Department of Chemistry, University of California, Davis, California 95616.
authors.forename: Mark
authors.initials: M
authors.lastname: Niemeyer
authors.forename: Philip P.
authors.initials: PP
authors.lastname: Power