Design and investigation of calamatic liquid crystals: Schiff base (‒CH˭N), chalcone (‒CO‒CH˭CH‒), and ester (‒COO‒) linkage group contain rigid rod shape with various terminal parts

GRAPHICAL ABSTRACT

ABSTRACT

The mesomorphic properties of linear schiff base-chalconyl ester homologous series can be designed in a predictable fashion with using various alcohol and para-tert-butyl phenol. We have synthesized total 14 novel liquid crystalline compounds and divided into two parts, i.e, series-1 (D₁ to D₁₀) and series-2 (E₁ to E₄). The result of both the series are compared and discussed. These compounds possess a rod-like geometry with rigid linear spacers and possessing smectic C and smectic A phases, while nematogenic phase was achieved by increasing the flexibility and broadening of tail-ended group in molecule. The texture image of mesophases is needle; rod like; broken fan type and nematic texture images are the type of schlieren and threaded in some homologue. All these compounds were characterized by elemental analyses and spectroscopic techniques such as FTIR and ¹H and ¹³C [NMR] spectroscopies. The mesomorphic properties of these compounds were observed by optical polarized light microscopy and differential scanning calorimetry.

KEYWORDS:

• Calamatic
• enantiotropic
• liquid crystal
• nematic
• smectic

Acknowledgments

Authors acknowledge thanks to Dr. R. R. Shah, principal of K. K. Shah Jarodwala Maninagar Science College, Ahmedabad. Author also gratefully thanks to Anuj S. Sharma (Chemistry department, Gujarat University) and Akshara. P. Shah (Chemistry department, Mumbai University) for giving fruitful discussions in DSC and UV analysis.