Synthesis, Characterization and Study of Liquid Crystal Behavior of Linear-Shaped Mesogens Containing Cyano and Alkyl as a Terminal Groups
DOI:
https://doi.org/10.31185/wjps.845Keywords:
liquid crystal, heterocyclic, Nematic phase, Smectic phaseAbstract
A novel series of liner-shaped liquid crystalline compounds containing thiazolidine-2,4-dione moieties with cyano and alkyl as terminal groups were synthesized and characterized. The molecular design incorporated a thiazolidine-2,4-dione unit linked to flexible alkyl chains via Knoevenagel condensation, yielding mesogens with varying terminal lengths. Structural confirmation was achieved through FT-IR, ¹H-NMR, and mass spectrometry. Mesomorphic properties were investigated using polarized optical microscopy (POM) and differential scanning calorimetry (DSC). All compounds [V] 4,5,6,8 exhibit liquid crystal properties, while, compound [V]3 do not show mesomorphic behavior. Odd-even effects were observed in transition temperatures, highlighting the influence of alkyl chain length on mesophase stability.
References
[1] S. Y. Kotian, L. Avinash, H. A. Shivakumar, et al., "Small molecule based five-membered heterocycles: A view of liquid crystalline properties beyond the biological applications," J. Mol. Liq., vol. 297, p. 111686, 2020, doi: 10.1016/j.molliq.2019.111686.
[2] Z. Zhang, X. Yang, Y. Zhao, F. Ye, and L. Shang, "Liquid crystal materials for biomedical applications," Adv. Mater., vol. 35, no. 36, p. e2300220, 2023, doi: 10.1002/adma.202300220.
[3] N. H. Karam, A. N. Kurdi, and A. H. Al-Dujaili, "Designed new mesogens via Vilsmeier–Haack reagent: synthesis and phase transition study," Phase Transit., vol. 95, no. 8–9, pp. 634–641, 2022, doi: 10.1080/01411594.2022.2096024.
[4] N. H. Karam, H. T. Jumbad, and A. H. Al-Dujaili, "Synthesis and characterization of heterocyclic compounds derived from 4-hydroxy and 4-amino acetophenone," Ibn Al-Haitham J. Pure Appl. Sci., vol. 26, no. 3, pp. 296–312, 2013.
[5] M. A. Jabar and N. H. Karam, "Designed new mesogens containing 5H-thiazolo[3,4-b][1,3,4]thiadiazole: Synthesis and investigation of liquid crystal properties," AIP Conf. Proc., vol. 2457, p. 030003, 2023, doi: 10.1063/5.0120896.
[6] E. A. Abdel-Kareem and N. H. Karam, "Synthesis, characterization and study the liquid crystalline properties of some new bent compounds derived from diethylpyrimidine-2,4,6(1H,3H,5H)-trione," Adv. J. Chem. A, vol. 8, no. 3, pp. 495–503, 2025, doi: 10.48309/AJCA.2025.472233.1631.
[7] N. H. Karam, H. R. T. Ivan, and H. T. Jumbad, "Synthesis, characterization and study of the liquid crystalline behavior of four and six heterocyclic compounds," Iraqi J. Sci., vol. 57, no. 3B, pp. 1876–1890, 2016.
[8] A. A. Fatima, N. H. Karam, and H. T. Jumbad, "Synthesis, characterization and study of liquid crystalline behavior of new bent core mesogens derived from isophthalic acid," Ibn Al-Haitham J. Pure Appl. Sci., vol. 29, no. 1, pp. 150–165, 2016. [Online]. Available: https://www.iasj.net/iasj/download/aa6b2dcbd3d9b5d5
[9] K. A. Amine and N. H. Karam, "Synthesis, Characterization, and Study of Liquid Crystals Properties of New Five Heterocyclic Compound," Ibn Al-Haitham J. Pure Appl. Sci., vol. 38, no. 2, 2025, doi: 10.30526/38.2.3354.
[10] A. Sharma, R. Kizhakidathazhath, and J. P. F. Lagerwall, "Impact of mesogenic aromaticity and cyano termination on the alignment and stability of liquid crystal shells," Soft Matter, vol. 19, pp. 2637–2645, 2023, doi: 10.1039/D3SM00041A.
[11] G. A. Pi̇rbudak and Y. G. Sıdır, "Optical properties, changes in electronic transitions in solvent media and dipole moments of nematic liquid crystals containing cyano group: Absorbance, fluorescence spectroscopy and reactivity parameters," J. Lumin., vol. 286, p. 121329, 2025, doi: 10.1016/j.jlumin.2025.121329.
[12] N. H. Karam, N. R. Jber, and A. H. Al-Dujaili, "A new series of triazine-core based mesogenic derivatives: Synthesis, characterization and mesomorphic study," Mol. Cryst. Liq. Cryst., vol. 675, no. 1, pp. 39–48, 2019, doi: 10.1080/15421406.2019.1624032.
[13] N. H. Karam and K. S. Alaa, "Synthesis, characterization and study of mesomorphic behavior of new bent and linear core compounds containing heterocyclic," Ibn Al-Haitham J. Pure Appl. Sci., vol. 30, no. 3, pp. 195–210, 2017, doi: 10.30526/30.3.1615.
[14] M. Shahnaz, "Synthesis and characterization of heterocyclic liquid crystals," J. Drug Deliv. Ther., vol. 3, no. 6, pp. 96–101, 2013, doi: 10.22270/jddt.v3i6.714.
[15] A. J. Athraa and N. H. Karam, "Design of new V-shaped thermotropic liquid crystals containing heterocyclic," Ibn Al-Haitham J. Pure Appl. Sci., vol. 36, no. 2, pp. 251–258, 2023, doi: 10.30526/36.2.3046.
[16] N. H. Karam, M. A. Jabar, and A. H. Al-Dujaili, "Synthesis and liquid crystalline properties of novel series containing 5H-thiazolo[3,4-b][1,3,4]thiadiazole unit with Schiff base and azo linkage," Mol. Cryst. Liq. Cryst., 2024, doi: 10.1080/15421406.2024.2356979.
[17] I. Dierking, Textures of Liquid Crystals. Weinheim: Wiley-VCH, 2003, doi: 10.1002/3527602054.
[18] J. W. Goodby, "Introduction to defect textures in liquid crystals," in Handbook of Visual Display Technology, 2nd ed., J. Chen, W. Cranton, and M. Fihn, Eds. Cham: Springer, 2016, pp. 1897–1924, doi: 10.1007/978-3-540-79567-4_82.
[19] G. W. Gray, Molecular Structure and the Properties of Liquid Crystals. New York: Academic Press, 1962.
[20] O. A. Alhaddad, M. M. Naoum, A. A. Fahmi, et al., "Mesophase behavior of four-ring ester/azomethine/ester liquid crystals in pure and mixed states," Liq. Cryst., vol. 49, no. 10, pp. 1395–1402, 2022, doi: 10.1080/02678292.2022.2037768.
Downloads
Published
Issue
Section
License
Copyright (c) 2025 Hassan Jabori, Nisreen H. Karam
This work is licensed under a Creative Commons Attribution 4.0 International License.
