Determination de la structure de perfluoroalcenes a chaines longues par R.M.N. du19F : lère Partie : pefluoroalcenes-1

After a review of 1-perfluoroalkene R_FCFCF₂ synthesis, with R_FC₄F₉, C₅F₁₁, C₆F₁₃, we have studied their fine structures by ¹⁹F N.M.R. This study has led us to first generalize the rules set for the chemical shifts and coupling constants of olefinic fluorine atoms of fluoropropene and their derivatives. Then, we have been able to determinate unambiguously the chemical shifts of the difluoromethylene groups of the perfluorinated chains. We have thus shown, by irradiation, that inversions may take place in the chemical shifts of the CF₂ groups at the β and γ position of the double bond.