Preparation and properties of laterally multifluorinated benzoxazole-based nematic mesogens

ABSTRACT

Series of laterally multifluorinated heterocyclic compounds, 2-(2ʹ,3-difluoro-4ʹ-alkoxy-1,1ʹ-biphenyl-4-yl)-benzoxazole derivatives (nPF(2)PF(3)Bx), are prepared and characterised. They mainly display enantiotropic nematic mesophases with wider mesophase ranges of 12–107°C (heating process) and 22–134°C (cooling process) than the corresponding analogues. The enhanced nematic mesophase stability is achieved via slightly increasing inter-ring twist angle with inter-ring lateral fluorine substitute in biphenyl unit, as well as through improving the molecular polarity with multifluorine substitutes. Meanwhile, two inter-ring lateral fluorine atoms lead to a decrease in melting/clearing points and a wide nematic mesophase range, which makes it possible for heterocyclic mesogens nPF(2)PF(3)Bx to use in nematic liquid crystal display mixtures.

GRAPHICAL ABSTRACT

KEYWORDS:

• Heterocyclic mesogens
• enantiotropic nematic mesophase
• multifluorine substituent
• benzoxazole-liquid crystals
• photophysical properties

Acknowledgements

The authors thanks for the financial support by the Key Technologies R&D Program of Shaanxi Province (2014K10-06), National Science Foundation Committee of China (51373092, 21543012), Specialized Research Fund for the Doctoral Program of Higher Education (20130202120010), Program for Key Science & Technology Innovation Team of Shaanxi Province (2015KCT-13) and the Fundamental Research Funds for the Central Universities (GK201703030, GK201603058, GK201501007, GK201501002).

Disclosure statement

No potential conflict of interest was reported by the authors.

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Funding

The authors thanks for the financial support by the Key Technologies R&D Program of Shaanxi Province (2014K10-06), National Science Foundation Committee of China (51373092, 21543012), Special Research Fund for the Doctoral Program of Higher Education (20130202120010), Program for Key Science & Technology Innovation Team of Shaanxi Province (2015KCT-13) and the Fundamental Research Funds for the Central Universities (GK201703030, GK201603058, GK201501007, GK201501002).