Isomérie Conformationnelle autour de la Liaison Carbone–Carbone dans les Sels de Propénylylidène Ammonium

¹H n.m.r. measurements of a series of propenylylideneammonium salts at temperatures varying from ?90 °C to 70 °C reveal the existence of two conformers. Values of chemical shifts and coupling constants are explained by rotation about a carbon–carbon bond; this hypothesis is supported by the ¹³C n.m.r. results. Free energies of activation are given for various substituents.