New Oligomeric Tungsten-Chalcogenide Anions

Robert W.M. Wardle, Sumit Bhaduri, Chung Nin Chau, James A. Ibers*

*Corresponding author for this work

Research output: Contribution to journalArticle

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Abstract

Upon acidification with acetic acid and precipitation from methanol solution with PPh+4, the WSe2-4 anion affords [PPh4]2-[(W3Se9)0.46(W3Se3O)0.54]. This compound crystallizes in the triclinic space group P1 with a = 9.085 (5) Å, b = 10.666 (4) Å, c = 13.407 (3) Å, α = 87.22 (2)°, β = 86.30 (3)°, γ = 84.11 (3)°, and Z = 1. The W3Se2-9 ion shows square-pyramidal coordination of Se atoms about the central W atom and tetrahedral coordination about the outer W atoms. The anion WS2-4 when acidified with H2SO4 yields W3S2-8, which may be isolated as its PPN+ salt. [PPN]2[W3S8] crystallizes in the triclinic space group P1 with a = 11.548 (2) Å, b = 15.175 (5) Å, c = 22.181 (5) Å, α = 104.90 (2)°, β = 90.80 (2)°, γ = 110.31 (2)°, and Z = 2. The central W atom has approximately square-planar coordination of S atoms, and the outer W atoms have tetrahedral coordination. Heating WSe2-4 in acetonitrile yields a complex mixture of anions that includes W3Se2-9, W2Se2-9, and W2Se2-10. Addition of elemental Se to the reaction mixture affords two isomers of W2Se2-10 and other dimers in smaller concentrations. [PPh4]2[(W2Se9)0.66(W2Se10)o.34] (P1, a = 10.556 (5) Å, b = 11.480 (6) Å, c = 22.324 (11) Å, α = 76.90 (2)°, β = 86.58 (2)°, γ = 79.28 (2)°, Z = 2) and [PPh4]2[W2Se10] (asymmetric/symmetric isomer ratio 0.73/0.27, P1, a = 10.678 (2) Å, b = 11.492 (3) Å, c = 22.392 (5) Å, α = 77.20 (2)°, β = 86.94 (2)°, γ = 79.81 (2)°, Z = 2) crystallize from these mixtures and have in common the (W2(μ-Se)2Se2)2- core. W2Se2-9 and the two isomeric W2Se2-10 anions differ only in the chain lengths of the chelating polyselenides. In these structures the WSe3 and WSe4 rings have conformations similar to cyclobutane and cyclopentane, respectively. Detailed structural data are reported. The 77Se NMR data for the selenides in DMF solution are presented and indicate that the solid-state structures remain intact in solution.

Original languageEnglish (US)
Pages (from-to)1747-1755
Number of pages9
JournalInorganic chemistry
Volume27
Issue number10
DOIs
StatePublished - Jan 1 1988

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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