The Chiral Pool as Valuable Natural Source: New Chiral Mesogens Made From Lactic Acid

Abstract

Twenty new enantiopure chiral materials have been synthesized, showing liquid crystalline phases of smectic (SmA*), twisted grain boundary (TGB) and cholesteric (N*) type. The central ester-linkage as well as the length of the attached alkyl-chains were varied in a systematic way and the effects of these structural changes on the liquid crystalline properties have been studied. The liquid crystalline phases were characterized by means of differential scanning calorimetry, polarisation microscopy as well as small angle X-ray diffraction (SAXS).

Keywords:

• Chiral pool
• chirality
• cholesteric phase
• liquid crystals
• smectic phase
• synthesis

Acknowledgment

We thank the Merck KGaA, Darmstadt, Germany for providing us with valuable starting materials as well as Prof. Dr. Gießelmann, Universität Stuttgart, Germany for giving us access to his SAXS- and WAXS-equipment.

Notes

^a PM/DSC [°C] (ΔH [kJ/mol]), Sm: smectic mesophase without subtype assignment, SmA*: chiral smectic A mesophase, TGB: twisted grain boundary mesophase without subtype assignment, Ch: cholesteric mesophase.

^b Detected by PM only.

^c Most likely a highly ordered smectic phase.