Decyl Ester Hydrochloride of Alanine as a Chiral Dopant in the Formation of Amphiphilic Cholesteric Liquid Crystals

Abstract

The decyl ester hydrochloride of the amino acid alanine is accessed as a chiral dopant in amphiphilic cholesteric liquid crystal formation. The achiral host detergents are alkylmethylammonium halides. The sense and magnitude of the induced helix is found to be dependent on the achiral host detergent. In the achiral host detergent tetradecyltrimethylammonium bromide (TDTMABr) the sense of the helical twist is found to be positive, while in the other hosts the sense of the helical twist is found to be negative. These results were interpreted in terms of the trans and cis rotamers associated with the ester linkage. 13C NMR is used to measure the rotamer populations. Each rotamer is thought to make an opposite but unequal contribution to the total twist.