Spiro-λ4-sulfanes with intramolecular sulfur-oxygen interactions: Syntheses and molecular structures

D. Szabó, M. Kuti, I. Kapovits, J. Rábai, Á Kucsman, Gy Argay, M. Czugler, A. Kálmán, L. Párkányi

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13 Citations (Scopus)


Three novel N-acetylated spiro-λ4-sulfanes with five-membered spirorings (fused with aromatic rings) and with two N heteroatoms (in (1)) or with N and O heteroatoms (in (2) and (3)) in axial positions have been prepared and their molecular structures determined by X-ray diffraction. The molecular structures of compounds (1-3) show trigonal bipyramidal geometry about the central sulfur atom. The rather long axial S-N bonds(1.93 Å)in he symmetric spiro-λ4-sulfane (1) exhibit the usual hypervalent character, whereas the S-N (1.73 and 1.80 Å) and S-O (2.23 and 2.07 Å) bond lengths in the unsymmetric spiro λ4-sulfanes (2) and (3) correspond to elongated covalent S-N bonds and highly polarized S-O hypervalent bonds, respectively. Each structure exhibits usual S-C(ar) bond lengths (1.79-1.81 Å). The axial N-S-N/O and the equatorial C(ar)-S-C(ar) angles lie in the intervals 173-179°and 98-103°, respectively. The conformations of (1-3) including the single-cis-single-trans isomerism of the endocyclic and exocyclic amide parts, the shape of the spirorings, and the relative positions of the equatorial aromatic rings are discussed in detail. In (1-3) the exocyclic carbonyl-oxygen approaches the central sulfur atom by 2.90,2.73 and 2.71 Å, respectively, leading to an effective intramolecular sulfur-oxygen interaction of 1,4-type. The S···O close contacts, however, do not alter appreciably the trigonal bipyramidal geometry about the central sulfur atom.

Original languageEnglish
Pages (from-to)1-16
Number of pages16
JournalJournal of Molecular Structure
Issue number1-2
Publication statusPublished - Aug 11 1997


  • Hypervalent bonds
  • Spiro-λ-sulfanes
  • Sulfur-oxygen interaction
  • X-ray diffraction

ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy
  • Organic Chemistry
  • Inorganic Chemistry

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