|
|||||
|
|
Self-Assembly and Fluorescence of Tetracationic Liquid Crystalline Tetraphenylethene |
|
| Authors: | Jakob Knelles Dr Stuart Beardsworth Korinna Bader Dr Johanna R Bruckner Andrea Bühlmeyer Robert Forschner Kevin Schweizer Dr Wolfgang Frey Prof?Dr Frank Giesselmann Prof?Dr Yann Molard Prof?Dr Sabine Laschat |
| Institution: | 1. Institut für Organische Chemie, Universität Stuttgart, Germany
These coauthors contributed equally to this work.;2. Institut für Organische Chemie, Universität Stuttgart, Germany;3. Institut für Physikalische Chemie, Universität Stuttgart, Germany;4. University of Rennes, CNRS, ISCR, UMR 6226, ScanMAT – UMS, 2001 Rennes, France |
| Abstract: | A series of tetraguanidinium tetraphenylethene (TPE) arylsulfonates with different chain lengths was prepared via ionic self-assembly of tetraguanidinium TPE chloride and the respective methyl arylsulfonates. Liquid crystalline properties were studied by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction. Tetraguanidinium TPE arylsulfonates with chain lengths of C8–C12 displayed hexagonal columnar mesophases over a broad temperature range, while derivatives with longer chains showed oblique columnar phases. In solution all compounds displayed aggregation-induced emission behaviour. Temperature-dependent luminescence spectra of the bulk phase of the tetraguanidinium TPE arylsulfonate with C14 side chains revealed a strong luminescence both in the solid state and the oblique columnar mesophase. The emission behaviour was rationalized by a unique combination of restriction of intramolecular rotation of the TPE core, Coulomb interaction between the guanidinium cations and π–π interactions of the anionic arylsulfonate moieties. |
| Keywords: | aggregation-induced emission fluorescence liquid crystals ionic self-assembly tetraphenylethene |