Synthesis, Structure, and Spectroscopy of [PPh4]2[(NC)Cu(μ-Se)2M(μ-Se)2Cu(CN)]·CH3CN and [PPh4]2[(NC)Cu(μ-Se)2MSe2] (M = Mo, W)

Robert J. Salm, James A. Ibers*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

[PPh4]2[MoSe4] and [PPh4]2[WSe4] react with 2 equiv of CuCN in CH3CN to afford [PPh4]2[(NC)Cu(μ-Se)2Mo(μ-Se)2Cu(CN)]·CH3CN (1) and [PPh4]2[(NC)Cu(μ-Se)2W(μ-Se)2Cu(CN)]·CH3CN (2), respectively. Compounds 1 and 2 are isostructural. Compound 1 crystallizes in the triclinic space group C1i-P1 with two formula units in a cell of dimensions a = 13.208(3) Å, b = 14.254(3) Å, c = 14.573(3) Å, α= 72.47(3)°, β = 74.09(3) °, and γ = 79.12(3)° at 113 K. Full anisotropic refinement of the structure on F02 led to a value of R(F) = 0.028 for those 7546 data having F02 >2σ(F02). The [(NC)Cu(μ-Se)2Mo(μ-Se)2Cu(CN)]2− anion of 1 comprises two CuCN fragments ligating the opposite edges of a tetrahedral [MoSe4]2− moiety; the Cu–Mo–Cu angle is 179.13(2)°;. Compounds 1 and 2 display an IR band at 2250 cm−1, which may be assigned to a CN stretching mode of the CH3CN solvate. Such a solvate molecule was found in the crystal structure of 1. The 77Se NMR spectra show a resonance at 1195 ppm for 1 and 920 ppm for 2. Addition of excess PMe2Ph to solutions of 1 and 2 results in the formation of [PPh4]2[(NC)Cu(μ-Se)2MoSe2] (3) and [PPh4]2[(NC)Cu(μ-Se)2WSe2] (4), respectively. Compounds 3 and 4 are isostructural. Compound 3 crystallizes in the monoclinic space group C62h-C2/c with four formula units in a cell of dimensions a = 11.254(2) Å, b = 20.153(4) Å, c = 20.191(4) Å, and β = 91.74(3)° at 113 K. Full anisotropic refinement of the structure on F02 led to a value of R(F) = 0.055 for those 3588 reflections having F02 > 2σ(F02)· The [(NC)Cu(μ-Se)2MoSe2]2− anion of 3, which has a crystallographically imposed 2-fold axis, comprises a CuCN fragment ligated across an edge of the tetrahedral [MoSe4]2− moiety. The 77Se NMR spectra show resonances at 1030 and 1820 ppm for compound 3 and at 782 and 1383 ppm for compound 4. The remaining NMR, IR, and electronic spectroscopic data of the four title compounds are also consistent with their solid-state structures.

Original languageEnglish (US)
Pages (from-to)4216-4220
Number of pages5
JournalInorganic chemistry
Volume33
Issue number19
DOIs
StatePublished - Sep 1 1994

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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