Mechanisms of enantiomeric resolution in cyclodextrin-modified capillary electrophoretic separations of binaphthyl compounds

The enantiomers of 1,1′‐bi‐2‐naphthol, 1,1′‐binaphthyl diyl hydrogen phosphate, and 1,1′‐binaphthyldicarboxylic acid are separated using capillary electrophoresis with cyclodextrins added to the running buffer. It is demonstrated that the type and concentration of cyclodextrin employed are critical for maximum enantiomeric resolution. A modified version of a previously described model of enantiomeric separations in capillary electrophoresis is shown to support the observed separation behavior. Molecular modeling is employed to calculate interaction energies between the various enantiomers and cyclodextrins. A reasonable correlation between these computationally derived interaction energies and separation behavior resulted from a statistical mechanical treatment of the molecular modeling data. The importance of hydrogen bonding in inclusion complex formation was probed and the effects of minimization and solvation in molecular modeling calculations are also discussed. © 1995 Wiley‐Liss, Inc.