Antiferroelectric liquid crystals derived from a new optically active (R)-3-ethylmercapto-2-methylpropionic acid

Abstract

A new optically active (R)-3-ethylmercapto-2-methylpropionic acid has been synthesized using D(-)—2,10-camphorsultam as a chiral auxiliary. The optical purity of the acid obtained was greater than 98 per cent. Its derivatives, (R)-4-(3-ethylmercapto-2-methylpropionyl)phenyl 4′-alkoxybiphenyl-4-carboxylates (EMMPPmBC; m = 7–16), have been prepared for the investigation of liquid crystalline properties as a function of peripheral alkyl chain length. Optical studies showed that all members exhibited an antiferroelectric S∗c_A phase. The results also indicate that a lengthened alkyl chain length is favoured for S_cA ∗ phase formation.