A STUDY OF THE STRUCTURE AND CHIRAL SELECTIVITY OF MICELLES OF 2 ISOMERIC D-GLUCOPYRANOSIDE-BASED SURFACTANTS

We have synthesised the sodium salts of two isomeric surfactants that differ in the anomeric orientation of the C-14 hydrocarbon chain to th e D-glucopyranoside fused ring structure, containing a phosphate polar head group, The inclusion of alpha- and beta-anomers in the separatio n buffer, using micellar electrokinetic capillary chromatography (MECC ) shows that the latter is the superior chiral selector, The critical micelle concentration (cmc) for both surfactants was around 0.6 mM, an d the mean aggregation number is 65 for both anomers. In an attempt to understand the possible mechanism of chiral discrimination, we have c alculated minimum energy conformations of micelles produced by these s urfactants, and have established the importance of their chiral head g roups and the sodium counter-ions in the discriminating process, We ha ve also investigated the micro-structures of the two surfactants by tr ansmission electron microscopy, This technique shows that the two enan tiomers aggregate very differently; whereas the alpha-anomer shows ran domly orientated string-like forms the beta-anomer forms ordered 'whor l' arrays.