The "F and 13C NMR Studies on the Structures of Hexafluoropropene Trimers

Abstract

The structures of three isomeric trirners of hexafluoropropene prepared by various methods have been examined by the "F and 'Sc NMR spectra. Their stuctures are, perfluoro-2, 4- dimethy1-3-heptene [(E) and (Z) T-1] (bp 106°C), perfluoro-3-(1-methylethyl)-4-methy1-2- pentene (T-2) (110°C), and perfluoro-3-ethy1-2, 4-dimethyl-2-pentene (T-3) (114°C) (Fig.1). The chemical shifts and the coupling constants of the "F (Figs.3, 6 and 7) and "C NMR (Figs.9, 11 and 13) spectra were satisfactorily interpreted in terms of structures T-1, T-2 and T-3, but were inconsistent with alternative structures T-1', T-2' and T-3'.