Cavallo, G.; Abate, A.; Rosati, M.; Paolo Venuti, G.; Pilati, T.; Terraneo, G.; Resnati, G.; Metrangolo, P.: Tuning of Ionic Liquid Crystal Properties by Combining Halogen Bonding and Fluorous Effect. ChemPlusChem 86 (2021), p. 469-474
10.1002/cplu.202100046
Open Access Version
Abstract:
We report halogen-bonded complexes between 1-polyfluoroalkyl-3-alkylimidazolium iodides and mono-iodoperfluoroalkanes of different chain lengths or di-iodoperfluorooctane. 19F NMR analyses revealed that the preferred stoichiometry between the donors and acceptors is 1 : 1 in the cases of the mono-iodoperfluoroalkanes, and 2 : 1 with di-iodoperfluorooctane, as a result of the monodentate behavior of the iodide anion (halogen bond acceptor). Single crystal X-ray diffraction analyses showed the presence of a perfluorinated superanion, which interdigitates with the cation fluorinated chains, favoring the formation of lamellar structures. All of the obtained supramolecular complexes exhibit enantiotropic liquid crystalline phases over a broad range of temperatures. Most of the obtained complexes show melting points lower than 100 °C, two of them being liquid at room temperature, thus representing a new family of fluorinated ionic liquid crystals.