Synthesis, characterization and photophysical study of cholesterol functionalized azo-based room temperature liquid crystals

• Published in: Journal of molecular structure 2023-10, Vol.1289, p.135776, Article 135776
• Main Authors: Mali, Hitendra, Sharma, Vinay S., Rathod, Suryajit L., Sharma, Anuj S., Shrivastav, Pranav S., Prajapati, Hemant R.
• Format: Article
• Language: English
• Subjects: Azo dye; Cholesterol; Enantiotropical; Ester; Smectic phase
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2023.135776

•A newly cholesterol interconnected azo-ester mesogens has been designed and characterized.•All four azo mesogens showed smectic mesophase with broad temperature range.•All four compounds displayed liquid crystalline properties at room temperature.•All cholesterol based materials exhibited higher thermal stability.•The structure-property relationship has been discussed for parent azo mesogens.•These azo-ester based molecular systems adopted good photophysical properties. Four new liquid crystalline materials (HA1-HA4) with cholesteryl group and azo-ester linking group interconnected with two-side substituted flexible alkoxy side chains were deliberated and synthesized. The structure confirmation of the azo mesogens was investigated by using FT-IR, 1H NMR, and 13C NMR techniques. The phase behavior of the materials was investigated by crossed polarizing optical microscopy (POM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) techniques. All four targeted materials shows smectic type mesogenic properties and further stabilized up to room temperature to lower temperature. The structure-property relationship of present azo-based materials was discussed to investigate the scope of mesogenic properties. All four materials (HA1-HA4) display wide temperature range mesophase as 52.5 °C, 54.7 °C, 52.7 °C, and 54.1 °C. The photoresponsive properties of the azo-based bi-substituted materials were well examined by UV study. [Display omitted]