Flavylium Salts: A Blooming Core for Bioinspired Ionic Liquid Crystals

Robert Forschner (1) , Jakob Knelles (1) , Korinna Bader (1) , Carsten Müller (1) , Wolfgang Frey (1) , Andreas Köhn (1) , Yann Molard (2) , Frank Giesselmann (1) , Sabine Laschat (1)

1 Universität Stuttgart [Stuttgart]
2 ScanMAT - Synthèse Caractérisation Analyse de la Matière

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 (Lam ) phases, whereas higher substituted flavylium salts showed Col as well as ordered and disordered columnar (Col , Col ) 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.

Mots clés: X-ray diffraction; fluorescence; UV/Vis spectroscopy; ionic liquid crystals; self-assembly

Domaines: Chimie

Robert Forschner, Jakob Knelles, Korinna Bader, Carsten Müller, Wolfgang Frey, et al.. Flavylium Salts: A Blooming Core for Bioinspired Ionic Liquid Crystals. Chemistry - A European Journal, 2019, 25 (56), pp.12966-12980. ⟨10.1002/chem.201901975⟩. ⟨hal-02308468⟩