Conductive plastic crystal phases of the 1-alkyl-2-methyl pyrrolinium TFSA salts

Characterization of a new family of salts, based on a number of 1-alkyl-2-methyl pyrrolinium cations and the bis(trifluoromethane sulfonyl) amide anion (TFSA), is presented. From the thermal analysis, conductivity and X-ray diffraction (XRD) measurements, at least one of the compounds of the family, 1-ethyl-2-methyl pyrrolinium TFSA, was found to exhibit plastic crystal phases before melting and to exhibit high conductivity in the solid state (1×10⁻⁴ S cm⁻¹ at 25 °C). This plastic crystal behaviour is discussed in comparison with other members of this pyrrolinium salt family.