Preparation and chiral recognition of a mono[6A-N-1-(2-hydroxy)-phenylethylimino-6A-deoxy]-β-cyclodextrin HPLC stationary phase

A novel chiral stationary phase (CSP) is obtained by linking the beta-CD to a chiral block (commercially available phenylglycinol) by rigid C = N bond. This chiral stationary phase exhibites good enantioselectivity for several alkylaromatic alcohols and a variety of ferrocene derivatives under reversed-phase conditions, with the best Rs value achieve up to 6.19. The hydrogen bonding interaction may be the primary factor, also pi-pi interaction or dipole-dipole interaction has some effect on chiral separation. The dependence of the natural logarithms of retention and selectivity factors (Ink' and In alpha) on the inverse of temperature 1/T (van't Hoff plots) is used to determine thermodynamic data referring to the separation of the enantiomers. Calculated thermodynamic constants Delta(Delta H degrees), Delta(Delta S degrees), and Delta(Delta G degrees) are applied to help understand of the thermodynamic driving forces for retention and enantio-recognition for this chromatographic system. It can be concluded that the separations for all the investigated analytes on this CSP are enthalpically favored.