All-cis 1,2,3,4,5,6-hexafluorocyclohexane is a facially polarized cyclohexane
Abstract
The highest-energy stereoisomer of 1,2,3,4,5,6-hexafluorocyclohexane, in which all of the fluorines are ‘up’, is prepared in a 12-step protocol. The molecule adopts a classic chair conformation with alternate C–F bonds aligned triaxially, clustering three highly electronegative fluorine atoms in close proximity. This generates a cyclohexane with a high molecular dipole (μ = 6.2 D), unusual in an otherwise aliphatic compound. X-ray analysis indicates that the intramolecular Fax···Fax distances (∼2.77 Å) are longer than the vicinal Fax···Feq distances (∼2.73 Å) suggesting a tension stabilizing the chair conformation. In the solid state the molecules pack in an orientation consistent with electrostatic ordering. Our synthesis of this highest-energy isomer demonstrates the properties that accompany the placement of axial fluorines on a cyclohexane and the unusual property of a facially polarized ring in organic chemistry. Derivatives have potential as new motifs for the design of functional organic molecules or for applications in supramolecular chemistry design.
Citation
Keddie , N S , Slawin , A M Z , Lebl , T , Philp , D & O'Hagan , D 2015 , ' All- cis 1,2,3,4,5,6-hexafluorocyclohexane is a facially polarized cyclohexane ' , Nature Chemistry , vol. 7 , no. 6 , pp. 483-488 . https://doi.org/10.1038/nchem.2232
Publication
Nature Chemistry
Status
Peer reviewed
ISSN
1755-4330Type
Journal article
Description
This work was generously supported by the Engineering and Physical Sciences Research Council (EPSRC) and the European Research Council (ERC).Collections
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