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image of Synthesis and Phase Transition Behaviors of Laterally Disubstituted Liquid Crystals Containing 2,5-Dimethyl-1,4-phenylenediamines

Abstract

A new series of low molar mass mesogens having double lateral substituents were prepared and characterized with the objective to explore the effect of structure modification on the mesomorphic behavior. The molecular structure has three aromatic rings at the centre core system, which is connected by an imine linking group, two flexible alkyloxy chains at both sides of molecules and two lateral methyl groups attached to the core system. This low molar mass mesogen is known as bis(4-alkyloxybenzylidene)-2,5-dimethyl-1,4-phenylenediamine with different numbers of carbon (n) at the alkyloxy chain. Molecular structures were confirmed infrared and nuclear magnetic resonance spectroscopic and mass spectrometric methods. Phase transition studies were conducted using a differential scanning calorimeter. Whereas, mesophase characterization was determined by polarizing optical microscopy and the temperature was varied with a temperature controller. The current core system of benzylidene-1,4-phenylenediamine showed good potential of exhibiting liquid crystal as all compounds were found to exhibit a nematic phase. Double lateral methyl atoms at the central mesogenic core had broadened the molecular width. This has caused a reduction in the overall lateral intermolecular attraction, and therefore, it exhibited a nematic phase. As the number of carbons at the alkyloxy chain increased, the clearing temperatures were observed to show a descending trend. A comparison of thermal properties was made between the current compounds with analogous compounds that do not possess any lateral substituent or have a single lateral substituent attached to the mesogenic core.

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2025-06-20
2025-11-14

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References

  1. Sohn J.I. Hong W.K. Choi S.S. Coles H.J. Materials 2014 7 3 2044 2061 10.3390/ma7032044 28788555
    [Google Scholar]
  2. Sun L. Huang W.M. Wang C.C. Ding Z. Zhao Y. Tang C. Gao X.Y. Polymeric shape memory materials and actuators. Liq. Cryst. 2014 41 3 277 289 10.1080/02678292.2013.805832
    [Google Scholar]
  3. Tian L.L. Chu F. Zhao W.X. Li L. Wang Q.H. Fast responsive 2D/3D switchable display using a liquid crystal microlens array. Opt. Lett. 2021 46 23 5870 5873 10.1364/OL.439127 34851911
    [Google Scholar]
  4. Kumari D.S. Shetty A. Ranjitha B.S. Vandana M. Shanker G. Alaasar M. Hedge G. Heliyon 2024 10 18 e37455 10.1016/j.heliyon.2024.e37455 39328507
    [Google Scholar]
  5. Agnieszka M. Jakub H. Natan R. Monika Z. Piotr H. Liq. Cryst. 2024 51 7 1256 1269 10.1080/02678292.2024.2361464
    [Google Scholar]
  6. Schadt M. Liq. Cryst. 2015 42 5-6 646 652
    [Google Scholar]
  7. Coates D. Liq. Cryst. 2015 42 5-6 653 665
    [Google Scholar]
  8. Goodby J.W. Mandle R.J. Davis E.J. Zhong T. Cowling S.J. What makes a liquid crystal? The effect of free volume on soft matter. Liq. Cryst. 2015 42 5 593 622 10.1080/02678292.2015.1030348
    [Google Scholar]
  9. Findeisen-Tandel S. Weissflog W. Baumeister U. Pelzl G. Shreenivasa Murthy H.N. Yelmaggad C.V. Beilstein J. Org. Chem. 2012 8 129 154
    [Google Scholar]
  10. Zhou M. Zhang J. Wang S. Boyer D. Guo H. Li W. Wu L. Laterally substituted ionic liquid crystals and the resulting rheological behavior. Soft Matter 2012 8 30 7945 7951 10.1039/c2sm25921d
    [Google Scholar]
  11. Kula P. Herman J. Pluczyk S. Harmata P. Mangelinckx G. Beeckman J. Synthesis and mesomorphic properties of laterally substituted 4,4′′′-dialkyl-p-quaterphenyls. Liq. Cryst. 2014 41 4 503 513 10.1080/02678292.2013.859755
    [Google Scholar]
  12. Boychuk A. Shibaev V. Cigl M. Hamplová V. Pociecha D. Bubnov A. Bobrovsky A. The role of lateral substituent size in azobenzene chromophores on photo- and chiro-optical properties of photoactive polymethacrylates. J. Photochem. Photobiol. Chem. 2023 440 114689 10.1016/j.jphotochem.2023.114689
    [Google Scholar]
  13. Collings P.J. Hird M. Introduction to Liquid Crystals. 1st ed UK Taylor & Francis 1998
    [Google Scholar]
  14. Gray G.W. Molecular Structure and Properties of Liquid Crystals. New York Academic Press 1962
    [Google Scholar]
  15. Weissflog W. Demus D. Thermotropic liquid crystalline compounds with lateral long‐chain substituents (II).: Synthesis and liquid crystalline properties of 1,4‐Bis [4‐substituted‐benzoyloxy]‐2‐n‐alkylbenzenes. Cryst. Res. Technol. 1984 19 1 55 64 10.1002/crat.2170190112
    [Google Scholar]
  16. Prajapati A.K. Pandya H.M. Bonde N.L. J. Chem. Soc. 2004 116 227 233
    [Google Scholar]
  17. Sinha D. Mandal P.K. Dabrowski R. High birefringence laterally fluorinated terphenyl isothiocyanates: Structural, optical and dynamical properties. Physica B 2014 441 100 106 10.1016/j.physb.2014.02.015
    [Google Scholar]
  18. Chen Q. Hird M. Liq. Cryst. 2015 42 877 886
    [Google Scholar]
  19. Ha S.T. Koh T.M. Yeap G.Y. Lin H.C. Beh J.K. Win Y.F. Boey P.L. Chin. Chem. Lett. 2009 20 1081 1084 10.1016/j.cclet.2009.03.048
    [Google Scholar]
  20. Ha S.T. Koh T.M. Lin H.C. Yeap G.Y. Win Y.F. Ong S.T. Sivasothy Y. Ong L.K. Heterocyclic benzothiazole-based liquid crystals: Synthesis and mesomorphic properties. Liq. Cryst. 2009 36 9 917 925 10.1080/02678290903131278
    [Google Scholar]
  21. Ha S.T. Koh T.M. Mol. Cryst. Liq. Cryst. 2010 528 10 22 10.1080/15421406.2010.504510
    [Google Scholar]
  22. Naoum M.M. Fahmi A.A. Ahmed N.H.S. Saad G.R. Liq. Cryst. 2015 42 11 1627 1637
    [Google Scholar]
  23. Naoum M.M. Metwally N.H. Abd eltawab M.M. Ahmed H.A. Polarity and steric effect of the lateral substituent on the mesophase behaviour of some newly prepared liquid crystals. Liq. Cryst. 2015 42 10 1351 1369 10.1080/02678292.2015.1049567
    [Google Scholar]
  24. Qaddoura M.A. Belfield K.D. Synthesis, characterization and texture observations of calamitic liquid crystalline compounds. Int. J. Mol. Sci. 2009 10 11 4772 4788 10.3390/ijms10114772 20087464
    [Google Scholar]
  25. Dierking I. Textures of Liquid Crystals. Weinheim Wiley-VCH Verlag 2003 10.1002/3527602054
    [Google Scholar]
  26. Prajapati A.K. Vora R.A. Pandya H.M. Effect of lateral hydroxy/alkoxy group on mesomorphism of azobenzene derivatives. Mol. Cryst. Liq. Cryst. Sci. Technol. Sect. A Mol. Cryst. Liq. Cryst. 2001 369 1 37 46 10.1080/10587250108030007
    [Google Scholar]
  27. Seou C.K. Ha S.T. Lee S.L. Yeap G.Y. Lin C.M. Lin H.C. Win Y.F. Synthesis and phase transition behaviours of laterally substituted liquid crystals containing methylhydroquinone: emerging of smectic C phase for higher homologues. Phase Transit. 2017 90 5 449 464 10.1080/01411594.2016.1219736
    [Google Scholar]
  28. Yeap G.Y. Hng T.C. Ito M.M. Mahmood W.A.K. Takeuchi D. Osakada K. Laterally brominated symmetric liquid crystal trimers with (S)-(-)-2-Methylbutyl-4′-(4″-phenyl)benzoate exhibiting N* and blue phases. Mol. Cryst. Liq. Cryst. 2009 515 1 215 229 10.1080/15421400902987594
    [Google Scholar]
  29. Yeap G.Y. Hng T.C. Mahmood W.A.K. Gorecka E. Takeuchi D. Osakada K. Chirality-induced liquid crystalline properties of seven-ring trimeric mesogens incorporating dual chiral centers. Mol. Cryst. Liq. Cryst. 2009 506 1 109 133 10.1080/15421400902841353
    [Google Scholar]
  30. Seou C.K. Ha S.T. Yip F.W. Yeap G.Y. Lett. Org. Chem. 2023 20 7 632 646 10.2174/1570178620666230131095431
    [Google Scholar]
/content/journals/loc/10.2174/0115701786370711250603060032
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Synthesis and Phase Transition Behaviors of Laterally Disubstituted Liquid Crystals Containing 2,5-Dimethyl-1,4-phenylenediamines
Bentham Science Publishers ; https://doi.org/10.2174/0115701786370711250603060032
/content/journals/loc/10.2174/0115701786370711250603060032
/content/journals/loc/10.2174/0115701786370711250603060032
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  • Article Type:     Research Article
Keywords: imine ; calamitic ; lateral ; phenylenediamine ; etherification ; nematic ; Liquid crystal

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