Flavylium Salts: A Blooming Core for Bioinspired Ionic Liquid Crystals |
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| Authors: | Robert Forschner Jakob Knelles Korinna Bader Carsten Müller Dr Wolfgang Frey Prof Dr Andreas Köhn Dr Yann Molard Prof Dr Frank Giesselmann Prof Dr Sabine Laschat |
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| Institution: | 1. Institut für Organische Chemie, Universität Stuttgart, Pfaffenwalding 55, 70569 Stuttgart, Germany;2. Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwalding 55, 70569 Stuttgart, Germany;3. Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany;4. CNRS, ISCR-UMR6226, ScanMAT-UMS 2001, University Rennes, 35000 Rennes, France |
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| Abstract: | Thermotropic ionic liquid crystals based on the flavylium scaffold have been synthesized and studied for their structure-properties relationship for the first time. The mesogens were probed by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD). Low numbers of alkoxy side chains resulted in smectic (SmA) and lamello-columnar (LamCol) phases, whereas higher substituted flavylium salts showed Colro as well as ordered and disordered columnar (Colho, Colhd) mesophases. Mesophase width ranged from 13 K to 220 K, giving access to room temperature liquid crystals. The optical properties of the synthesized compounds were probed towards absorption and emission properties. Strong absorption with maxima between 444 and 507 nm was observed, and some chromophores were highly emissive with quantum yields up to 99 %. Ultimately, mesogenic and dye properties were examined by temperature-dependent emissive experiments in the solid state. |
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| Keywords: | fluorescence ionic liquid crystals self-assembly UV/Vis spectroscopy X-ray diffraction |
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