Preparation and Structures of the 2.2.2-Cryptand(1+) Salts of the [Sb2Se4]2-, [As24S]2-, [As10S3]2-, and [As4Se6]2- Anions

Donna M. Smith, Chang Woo Park, James A. Ibers*

*Corresponding author for this work

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43 Scopus citations

Abstract

2.2.2-Cryptand(1+) salts of the [Sb2Se4]2-, [As2S4]2-, [As2S4]2-, and [As4Se6]2- anions have been synthesized from the reduction of binary chalcogenide compounds by K in NH3(l) in the presence of the alkali-metalencapsulating ligand 2.2.2-cryptand (4,7,13,16,21,24-hexaoxa-l,10-diazabicyclo[8.8.8]hexacosane), followed by recrystallization from CH3CN. The [Sb2Se4]2- anion, which has crystallographically imposed symmetry 2, consists of two discrete edge-sharing SbSe3 pyramids with terminal Se atoms cis to each other. The Sb-Set bond distance is 2.443(1) Å, whereas the Sb-Seb distance is 2.615(1) Å (t = terminal; b = bridge). The Seb-Sb-Set angles range from 104.78(4) to 105.18(5)°, whereas the Seb-Sb-Seb angles are 88.09(4) and 88.99(4)°. The 77Se NMR data for this anion in solution are consistent with its X-ray structure (δ 337 and 124 ppm, 1:1 intensity, -30 °C, CH3CN/CD3CN). Similar to this [Sb2Se4]2- anion, the [As2S4]2- anion consists of two discrete edge-sharing AsS3 pyramidal units. The As-St bond distances are 2.136(7) and 2.120(7) Å, whereas the As-Sb distances range from 2.306(7) to 2.325(7) Å. The Sb-As-St angles range from 106.2(3) to 108.2(3)°, and the Sb-As-Sb angles are 88.3(2) and 88.9(2)°. The [As10S3]2- anion has an 11-atom As10S center composed of six five-membered edge-sharing rings. One of the three waist positions is occupied by a S atom, and the other two waist positions feature As atoms with exocyclic S atoms attached, making each As atom in the structure three-coordinate. The As-As bond distances range from 2.388(3) to 2.474(3) Å. The As-S, bond distances are 2.181(5) and 2.175(4) Å, and the As-Sb bond distance is 2.284(6) Å. The [As4Se6]2- anion features two AsSe3 units joined by Se-Se bonds with the two exocyclic Se atoms trans to each other. The average As-Set bond distance is 2.273(2) Å, whereas the As-Seb bond distances range from 2.357(3) to 2.462(2) Å. The Seb-As-Se1 angles range from 101.52(8) to 105.95(9)°, and the Seb-As-Seb angles range from 91.82(7) to 102.97(9)°. The 77Se NMR data for this anion in solution are consistent with its X-ray structure (σ 564 and 317 ppm, 3:1 intensity, 25 °C, DMF/ CD3CN).

Original languageEnglish (US)
Pages (from-to)6682-6687
Number of pages6
JournalInorganic chemistry
Volume35
Issue number23
DOIs
StatePublished - Jan 1 1996

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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