Synthesis and mesomorphic properties of novel liquid crystal series with two chiral centres and their electro‐optic characteristics

Abstract

Three series of novel chiral liquid crystals containing biphenyl moiety with two chiral centres (diastereomer) were synthesized and characterized. The structures and thermal phase behaviour of target compounds were characterized using ¹H nuclear magnetic resonance, mass spectroscopy, elemental analysis, differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. All the compounds exhibit enantiotropic mesomorphic behavior. In this case, the chiral liquid crystalline molecules bearing the shorter length of alkyl chain (m = 3 and 4) show a mesomorphic dimorphism SmA*‐N* and the analogous compounds bearing the longer length of alkyl chain (m = 5 and 6) exhibit only one SmA* mesophase. Furthermore, the potential of SmA* mesophase for electro‐optics applications exploiting the electroclinic effect was explored. The electro‐optical properties of the SmA* phase, such as voltage‐transmittance effect, electroclinic effect, and electro‐optical response were also measured. As a consequence, the correlation between their electro‐optical properties and chemical structures of these compounds were investigated.

Key words:

• two chiral centres
• chiral smetic A
• electroclinic effect

Notes

Corresponding authors: (Tel: [phone] ext. 7403; Fax: [phone]; Email: [email protected])