Synthesis of laterally substituted α‐methylstilbene‐tolane liquid crystals

Abstract

Three series of α‐methylstilbene‐tolane liquid crystals, 4‐[2‐(4‐alkylphenyl)‐1‐ethynyl]‐4′‐fluoro‐α‐methylstilbene (3a–3e), 4‐[2‐(4‐alkylphenyl)‐1‐ethynyl]‐2′‐methyl‐4′‐fluoro‐α‐methylstilbene (4a–4e) and 4‐[2‐(4‐alkylphenyl)‐1‐ethynyl]‐3′‐methyl‐4′‐fluoro‐α‐methylstilbene (5a–5e), were synthesized and their phase transition temperatures characterized. All the α‐methylstilbene‐tolane liquid crystals exhibit an enantiotropic nematic phase. Compounds 5a–5e, which contain a lateral methyl group at the 3 position of the middle phenyl ring, display low melting points, a wide nematic range and a small enthalpy of fusion. Their potential applications for displays and laser‐beam steering are noted.

Acknowledgement

The authors are grateful to the National Science Council of the Republic of China for financial support of this work.