Babamale, Halimah Funmilayo and Ng, Si Ling and Tang, Wai Kit and Yam, WanSinn (2024) Azobenzene-Imidazolium ionic liquid crystals: Phase properties and photoisomerization in solution state. Journal of Molecular Structure, 1303. ISSN 0022-2860, DOI https://doi.org/10.1016/j.molstruc.2024.137494.
Full text not available from this repository.Abstract
This is the first report of phase properties and photoisomerization behaviour of a series of amphiphilic azobenzene-imidazolium derivatives. The cationic imidazolium moiety was functionalised with varying alkyl chain length (C10-C18) and connected to an azobenzene via a flexible ether spacer. Their phase transitional properties and photoisomerization in solution were modulated by the alkyl chains in the imidazolium moiety. C14 was the shortest chain length to induce the formation of a liquid crystal phase, wherein compounds having C14-C18 exhibited stable smectic A phase. All compounds photo switched from trans-to-cis isomers in solution when illuminated with UV radiation. DFT calculations revealed that the trans isomers could adopt two geometries, however, folded geometry (global minima) was thermodynamically more stable than the open chain structure. The long conjugate (C16) had a higher trans-cis isomerization barrier due to the multilayer folding geometry that reduced its structural flexibility as compared to the C10 homologue. The photo conversion efficiency (CE) was alkyl chain length dependent. The C10 salt had a larger CE than C16 homologue due to the transition gap between S1 excited state and ground surface is smaller in the former (0.211 eV) than that in the latter (0.278 eV), thus resulting in efficient photoisomerization in the former. © 2024
| Item Type: | Article |
|---|---|
| Funders: | Universiti Sains Malaysia [1001/PKIMIA/8011094] |
| Uncontrolled Keywords: | Chain length; Conversion efficiency; Density functional theory; Excited states; Geometry; Ionic liquids; Isomerization; Isomers; Liquid crystals; Multilayers; Amphiphilic azobenzene-imidazolia; Amphiphilics; DFT calculation; Imidazolium; Liquid crystal phase; Liquid crystal phasis; Multi-layer folding; Phase properties; Photoisomerization, DFT calculation; Photoisomerizations; Azobenzene |
| Subjects: | Q Science > QD Chemistry |
| Divisions: | Faculty of Science > Department of Chemistry |
| Depositing User: | Ms. Juhaida Abd Rahim |
| Date Deposited: | 11 Jul 2024 05:39 |
| Last Modified: | 11 Jul 2024 05:39 |
| URI: | http://eprints.um.edu.my/id/eprint/44753 |
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