Synthesis and Structural Characterization of Lithium Thiolates: Dependence of Association and Aggregation on Donor Hapticity and Ligand Size and Synthesis of the First Trimeric Lithium Thiolate [Li(THF)SR]3 and the Solvent-Separated Ion Pair [Li(12-crown-4)2][SR] (R = 2,4,6-tBu3C6H2)1

Karin Ruhlandt-Senge, Ulrich Englich, Mathias O. Senge, Scott Chadwick

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

The synthesis and structural characterization of several lithium thiolates are reported. Formation of discrete species can be achieved by careful variation of ligand size and donor hapticity, as exemplified by the monomeric formulation of Li(PMDTA)STrityl (PMDTA = N,N,N',N'',N''-pentamethyldiethylenetriamine, Trityl = CPh3), 1, and Li-(PMDTA)STrip, 2 (Trip = 2,4,6-iPr3C6H2), versus the dimeric species [Li(THF)2STrityl]2, 3, and [Li(TMEDA)-STrip]2, 4 (TMEDA = N,N,N'N'-tetramethylethylenediamine). By control of the stoichiometry of the donor, the first trimeric lithium thiolate [Li(THF)SMes*]3, 5 (Mes* = 2,4,6-tBu3C6H2), exhibiting a six-membered ring system and rare three-coordinate lithium centers, becomes available. In contrast, use of a crown ether leads to the isolation of the monomeric contact ion pair Li(12-crown-4)STrityl, 6, while employing the cumbersome - SMes* ligand allows for the isolation of the first solvent-separated lithium thiolate [Li(12-crown-4)2][SMes*], 7. All compounds were prepared by reacting the respective thiols with nBuLi in the presence of various donor adjuncts. The target molecules were characterized using 1H NMR and IR spectroscopy and melting point criteria. Crystal structure analysis was employed to determine solid state structures. Crystal data are as follows. 1: Cu Kα (λ = 1.541 78 Å) at 130 K, a = 12.152(3) Å, b = 15.260(3) Å, c = 14.764(5) Å, β = 106.90(2)°, V = 2619.6(12) Å3, Z = 4, monoclinic, space group P21/c, 2526 reflections (I > 2σ(I)), R = 0.064. 2: Cu Kα (λ = 1.541 78 Å) at 228 K, a = 15.805(7) Å, b = 9.206(4) Å, c = 18.923(7) Å, β= 99.74(3)̊, V = 2714(2) Å3, Z = 4, monoclinic, space group P21/n, 2047 reflections (I > 2σ(I)), R = 0.085. 3: Mo Kα (λ = 0.710 73 Å) at 213 K, a = 13.141(3) A, b = 12.381(2) Å, c = 14.664(3) Å, β = 94.84(3)°, V = 2377.3(8) Å3, Z = 2, monoclinic, space group P21/n, 2622 reflections (I > 2σ(I)), R = 0.052. 4: Cu Kα (λ = 1.541 78 Å) at 130 K, a = 18.906(4) Å, b = 9.516(2) Å, c = 25.617(5) Å, β = 92.75(3)°, V = 4603(2) Å3, Z = 4, monoclinic, space group I2/a, 2390 reflections (I > 2σ(I)), R = 0.067. 5: Mo Kα (λ = 0.710 73 Å) at 213 K, a = 9.991(2) Å, b = 17.934(4) Å, c = 20.314(4) Å, α = 83.36(3)°, β= 76.74(3)°, γ = 76.72(3)°, V = 3440.4(12) Å3, Z = 2, triclinic, space group P1, 6397 reflections (I > 2.5σ(I)), R = 0.063, 6: Mo Kα (λ = 0.710 73 Å) at 213 K, a = 10.542(2) Å, b = 12.821(3) Å, c = 18.729(4) Å, β = 102.22(3)°, V = 2474.0(9) Å3, Z = 4, monoclinic, space group P21/c, 4206 reflections (I > 2σ(I)), R = 0.086. 7: Mo Kα (λ = 0.710 73 Å) at 213 K, a = 10.134(2) Å, b= 19.800(4) Å, c = 18.423(4) Å, β = 93.15(3)°, V = 3691.0(13) Å3, Z = 4, monoclinic, space group P21/n, 4088 reflections (I > 2σ(I)), R = 0.092.

Original languageEnglish (US)
Pages (from-to)5820-5827
Number of pages8
JournalInorganic Chemistry
Volume35
Issue number20
DOIs
StatePublished - 1996

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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