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 p hosphate, and 1,1'-binaphthyldicarboxylic acid are separated using cap illary electrophoresis with cyclodextrins added to the running buffer. It is demonstrated that the type and concentration of cyclodextrin em ployed are critical for maximum enantiomeric resolution. A modified ve rsion of a previously described model of enantiomeric separations in c apillary electrophoresis is shown to support the observed separation b ehavior. Molecular modeling is employed to calculate interaction energ ies between the various enantiomers and cyclodextrins. A reasonable co rrelation between these computationally derived interaction energies a nd separation behavior resulted from a statistical mechanical treatmen t of the molecular modeling data. The importance of hydrogen bonding i n inclusion complex formation was probed and the effects of minimizati on and solvation in molecular modeling calculations are also discussed . (C) 1995 Wiley-Liss, Inc.