Influence of Mobile Phase and Temperature on Separation of 1,1′-Binaphthyl-2,2′-Diol Enantiomers with Brush Type Chiral Stationary Phases Derived from l-Leucine

Abstract

1,1′-Binaphthyl-2,2′-diol (BINOL) was analysed on three different chiral stationary phases comprising 3,5-dinitrobenzoyl-l-leucine as chiral selector. Chromatographic data were related to NMR measurements performed for the mixture of the soluble chiral selector and individual enantiomers of BINOL. The results indicate that the most important interactions for complexation are H-bondings accomplished through the hydroxyl protons of BINOL with carbonyl groups of 3,5-dinitrobenzoyl-l-leucine. Interactions between 3,5-dinitrobenzoyl and naphthyl aromatic units are not observed and that could explain the large variations of NMR spectra and HPLC chromatograms recorded at different temperatures.