REVERSALS IN BULK CHIRALITY IN A CHIRAL NEMATIC AMPHIPHILIC LIQUID-CRYSTAL ASSOCIATED WITH ACYLATED PROLINE AND THIAPROLINE

Chiral detergents derived from the acylation of naturally occuring ami no acids have been synthesised. These detergents have been used as chi ral dopants with the achiral host potassium laurate (KDD). A correspon dence has been found between the molecular stereochemistry in the mice lle surface and the resulting bulk chirality. The chiral dopants potas sium hexadecanoyl-L-proline (L-KHDP) and potassium hexadecanoyl-L-thia proline (L-KHDTP) with the host achiral KDD were found to cause invers ions in the sense of the twist, abnormal to the general case. These in versions in sense of twist were interpreted as originating from the co mpensation averaging of the cis-trans molecular conformations, derived from the rotation of the consituents about the C-N peptide bond. NMR evidence is presented to support this assertion.