Effects on Cyclopropane Geometry of Aromatic Substituents in the Bisected Conformation. The Structures of Spiro[cyclopropane‐1,9′‐[9H]fluorene] and 2,2‐Dichlorospiro[cyclopropane‐1,9′‐[9H]fluorene]

Mark E. Jason*, Judith C. Gallucci, James A Ibers

*Corresponding author for this work

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

The structures of spiro[cyclopropane‐1,9′‐[9H]fluorene] (1) and 2,2‐ dichlorospiro[cyclopropane‐1,9′‐[9H]fluorene] (2) have been determined by conventional single‐crystal X‐ray diffraction techniques. Compound 1 crystallizes with 32 molecules in the unit cell in space group C212v–Iba 2 of the orthorhombic system in a cell of dimensions a = 42.228(23), b = 27.318(17) and c = 7.664(8) Å. Compound 2 crystallizes with four molecules in the unit cell in space group C52h–P21/c of the monoclinic system in a cell of dimensions a = 8.451(3), b = 8.960(3), c = 15.882(5) Å and β = 97.31(1)°. The structures of 1 and 2 have been refined by full‐matrix least‐squares techniques to conventional R indices of 0.055 and 0.049, respectively. Relative to the bridgehead position, the cyclopropane ring in 1 contains a short distal bond of average value 1.496(9)Å and lengthened vicinal bonds averaging 1.531(11)Å. This geometry agrees qualitatively with a simple molecular orbital model for charge transfer from cyclopropane to an aromatic π‐system held in the bisected conformation. The cyclopropane ring in compound 2 contains C–C bond lengths of 1.537(3), 1.517(3) and 1.475(3) Å. These values cannot be explained by summing the expected changes induced by the aromatic and halogen substituents.

Original languageEnglish (US)
Pages (from-to)95-104
Number of pages10
JournalIsrael Journal of Chemistry
Volume21
Issue number2-3
DOIs
StatePublished - Jan 1 1981

ASJC Scopus subject areas

  • Chemistry(all)

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