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Updated: Feb 13, 2026

Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Can acyclic conformational control be achieved via a sulfur-fluorine gauche effect?
C Thiehoff1, M C Holland1,2, C Daniliuc1
1Organisch Chemisches Institut, and Excellence Cluster EXC 1003 , Cells in Motion , Westfälische Wilhelms-Universität Münster , Corrensstrasse 40 , Münster , Germany .
Abstract:
The gauche conformation of the 1,2-difluoroethane motif is known to involve stabilising hyperconjugative interactions between donor (bonding, σC-H) and acceptor (antibonding, σ*C-F) orbitals. This model rationalises the generic conformational preference of F-Cβ-Cα-X systems (φFCCX ≈ 60°), where X is an electron deficient substituent containing a Period 2 atom. Little is known about the corresponding Period 3 systems, such as sulfur and phosphorus, where multiple oxidation states are possible. Conformational analyses of β-fluorosulfides, -sulfoxides and -sulfones are disclosed here, thus extending the scope of the fluorine gauche effect to the 3rd Period (F-C-C-S(O) ; φFCCS ≈ 60°). Synergy between experiment and computation has revealed that the gauche effect is only pronounced in structures bearing an electropositive vicinal sulfur atom (S+-O-, SO2).
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