Asymmetric flavone-based liquid crystals: synthesis and properties |
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| Authors: | Daren J. Timmons Abraham J. Jordan Angelo A. Kirchon N. Sanjeeva Murthy Troy J. Siemers Daniel P. Harrison |
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| Affiliation: | 1. Department of Chemistry, Virginia Military Institute, Lexington, VA, USADarenT@usca.edu;3. Department of Chemistry, Virginia Military Institute, Lexington, VA, USA;4. New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, Piscataway, NJ, USA;5. Department of Applied Mathematics, Virginia Military Institute, Lexington, VA, USA |
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| Abstract: | A series of flavones (n-F) substituted at the 4′, and 6 positions was prepared, characterised by NMR (1H,13C), HRMS, and studied for liquid crystal properties. The 4′-alkoxy,6-methoxyflavones (4-F–16-F) exhibit varying ranges of nematic and smectic A phases as evidenced by polarised optical microscopy and differential scanning calorimetry (DSC). As the tail length is increased, the smectic phase becomes more prevalent. Smectic phases for (8-F–16-F) were further analysed by powder X-ray diffraction (XRD), and the rate of structural transformations was explored by combined DSC/XRD studies. Flavonol 6-F–OH was also prepared but no mesogenic behaviour was observed. The molecular structures of 6-F and 6-F–OH were determined by single-crystal XRD and help to explain the differences in material properties. Additionally, fluorescence and electrochemical studies were conducted on solutions of n-F. |
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| Keywords: | Liquid crystal thermotropic flavone heterocycle fluorescence combined DSC/XRD |
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