This study extends our interest in the synthesis and conformational behaviour of all-syn multivicinal fluoro alkane motifs. Specifically an all-syn 1,2,3,6,7,8-hexafluorooctane chain was assembled with a run of three fluorines, of the same stereochemical sense (syn) to the direction of the chain, on each side of an ethylene (–CH₂CH₂–) spacer to explore if the helical sense of the chain crosses the ethylene bridge. The solid state (X-ray) structure indicated a continuous helix however in solution (NMR) and by DFT computation, although the individual all-syn 1,2,3-trifluoro motifs maintain good helical integrity, the molecule is much more dynamic across the ethylene bridge. It was notable however that a low energy, non-helical conformer has a high molecular dipole (μ = 7.15 D) indicating a role for this skipped motif in soft materials such as liquid crystals or polar polymers.

Title

Organic & Biomolecular Chemistry

Publisher

Royal S C

Publisher Country

United Kingdom

Indexing

Thomson Reuters

Impact Factor

3.47

Publication Type

Both (Printed and Online)

Volume

15

Year

2020

Pages

878-887