Nuclear Magnetic Resonance Spectroscopy. Studies of 1,1,4,4-Tetrafluoro- 1,3-alkadienes

Abstract

1,1,4,4-Tetrafuoro-1,3-butadiene is indicated by dipole moment studies to exist in the s-trans conformation. The ^(19)F-^(19)F spin-spin coupling constants for this compound are surprisingly similar to those of bis-4,5-(difluoromethylene)cyclohexene and perfluoro-1,2-dimethylenecyclobutane, both of which substances have their double bonds held in s-cis configurations. The results are related to the mechanism of transmission of fluorine-fluorine spin-spin interactions and are inconsistent with a predominance of a "through-space" mechanism of coupling.

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