Syntheses and Characterization of the First Thallium Polysulfide Anions

Sandeep S. Dhingra, Mercouri G. Kanatzidis

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Abstract

The reaction of potassium tetrasulfide with thallium chloride in dimethylformamide (DMF) was investigated. The addition of the cations Ph4P+, Et4N+, and Me4N+ to this reaction afforded six new soluble thallium(I) polysulfide complexes, α-(Ph4P)2[Tl2(S4)2] (I), β-(Ph4P)2[Tl2(S4)2]·2DMF (II), β′-(Ph4P)2[Tl2(S4)2]·2DMF (III) γ-(Ph4P)2 [T12(S4)2]·DMF (IV), (Et4N)2[Tl2(S4)2] (V), and (Me4N)2[Tl2(S4)2] (VI). Compound I (pale yellow platelets) crystallizes in the triclinic space group P1¯ (No. 2) with unit cell dimensions a = 9.907(3) Å, b = 11.014(3) Å, c = 12.794(4) Å, α = 71.05(3)°, β = 87.33(3)°, y = 68.79(2)°, V = 1227(1) Å3 (at 23 °C), and Z = 1. Single-crystal X-ray diffraction studies show that compounds II and III are isostructural and crystallize in the monoclinic space group P21/c (No. 14). The unit cell dimensions of the pale orange crystals of II area a = 10.815(3)Å, b = 14.486(5) Å, c = 18.281(5) Å, β = 97.29(3)°, V= 2841(1) Å3 (at 23 °C), and Z = 2, and the unit cell dimensions of the deep red crystals of III are a = 10.810(5) Å, b = 14.480(8) Å, c = 18.294(7) Å, β = 97.37(3)°, V = 2839(2) Å3 (at 23 °C), and Z = 2. Compound IV (orange crystals) crystallizes in the monoclinic space group C2/c (No. 15) with unit cell dimensions a = 26.324(6) Å, b = 9.269(10) Å, c = 24.062(5) Å, β = 117.36(1)°, V = 5213(4) Å3 (at–120 °C), and Z = 4. Compound V (orange crystals) crystallizes in the monoclinic space group P21/n (No. 14) with unit cell dimensions a = 11.880(10) Å, b = 17.202(6) Å, c = 7.200(6) Å,β = 97.29(3)°, V = 1457(2) Å3 (at–100 °C), and Z = 2. Compound VI (pale orange platelets) crystallizes in the triclinic space group P1¯ (No. 2) with unit cell dimensions a = 6.160(3) Å, b = 9.683(6) Å, c = 10.160(5) Å, α = 66.05(4)°, β = 84.88(4)°, γ–80.64(4)°, V = 546(1) Å3 (at–100 °C), and Z = 1. Surprisingly, all the complexes (I–VI) stabilize the same [Tl2(S4)2]2− anions. Despite their different colors II and III are structurally identical. The anion features two trigonal pyramidal Tl+ centers each chelated by a tetrasulfide ligand and the third coordination site is satisfied by bonding a terminal sulfur atom of another TlS4 unit, forming a dimer. This bonding mode of the S42− ligands results in a new condensed inorganic ring system with a central, strictly planar, four-membered Tl2S2 rhombic unit and two five-membered TlS4 rings in an envelope configuration. The envelope configuration of the five membered TlS4 ring in the [Tl2(S4)2] 2− anions results in either the boat—boat or the chair—chair conformation. The reaction of potassium tetrasulfide with thallium chloride in acetonitrile afforded orange red crystals of K0.68Tl1.32S5 (VII). Compound (VII) crystallizes in the orthorhombic space group P212121 (No. 19) with unit cell dimensions of a = 6.630(4) Å, b = 16.989(6) Å, c = 6.499(2) Å, V = 727(1) Å3, and Z = 4. Compound VII is isostructural to the known K2S5 and Tl2S5 and consists of a S52 chain with Tl+ and K+ as charge-compensating cations. VII can be considered as a solid solution of the two known compounds. All complexes show similar UV/vis spectra in DMF with two absorptions at ∼432 and ∼617 nm. The solid-state far-IR spectra of all compounds exhibit strong absorptions in the 500–100-cm−1 region due to the S-S and M-S stretching frequencies; tentative assignments are reported.

Original languageEnglish
Pages (from-to)2298-2307
Number of pages10
JournalInorganic Chemistry
Volume32
Issue number11
DOIs
Publication statusPublished - Jan 1 1993

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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