Theoretical and experimental aspects of enantiomeric differentiation usingnatural abundance multinuclear nmr spectroscopy in chiral polypeptide liquid crystals

Liquid crystalline organic solutions of poly-gamma -benzyl-l-glutamate gene rate a sufficient differential ordering effect to visualize enantiomers usi ng multinuclear high-resolution NMR spectroscopy at natural isotopic abunda nce levels. Chiral discrimination can be observed through a difference in t he order-sensitive NMR observables, namely: proton-proton, carbon-proton an d carbon-carbon residual internuclear dipolar couplings, carbon chemical sh ift anisotropies, and deuterium quadrupolar splittings. In most cases, the enantiodifferentiation is large enough to allow determation of the enantiom eric excesses satisfactorily. All theoretical considerations and significan t experimental parameters that affect the efficiency of this methodology ar e presented and discussed. The various possible anisotropic NMR techniques provide a very reliable and powerful alternative to the current analytical techniques which operate in the isotropic phase.