Two-dimensional deuterium NMR spectroscopy of chiral molecules oriented ina polypeptide liquid crystal: Applications for the enantiomeric analysis through natural abundance deuterium NMR

We describe several two-dimensional NMR experiments to facilitate the analy sis of overcrowded proton-decoupled deuterium spectra of chiral molecules o riented in poly-gamma-benzyl-L-glutamate liquid crystalline solutions. Thes e 2D NMR experiments allow the correlation between the components of each q uadrupolar doubtet in the deuterium spectra and then their assignment on th e basis of chemical shift. The 2D pulse sequences proposed in this work wer e developed using the Cartesian spin-operator formalism for spin I = 1 nucl ei with a small quadrupolar moment, such as deuterons in high magnetic fiel d. The features and analytical potentialities of each pulse sequence are di scussed and compared. Illustrative applications of these sequences in natur al abundance deuterium NMR spectroscopyusing a 9.4 T magnetic field and sta ndard NMR equipment are reported and examined. With this technique, it is d emonstrated that quantitative measurements are possible within a precision of 10%.