Poly-γ-S-perillyl-l-glutamate and Poly-γ-S-perillyl-d-glutamate: Diastereomeric Alignment Media Used for the Investigation of the Alignment Process

Residual dipolar couplings (RDCs) offer additional information for structure elucidation by NMR spectroscopy. They are measured in anisotropic media, such as lyotropic liquid crystalline phases of polypeptides. Today, some suitable polypeptides are known. Nevertheless, structural influences of these polypeptides on the alignment properties are not really understood. Thus, which influence a chiral side chain has on enantiodiscrimination and whether we can improve the enantiodifferentiation significantly by adding an additional chiral center in the side chain are questions of interest. Therefore, new diastereomeric polypeptide-based alignment media with an additional chiral center in the side chain derived from perillyl alcohol were synthesized and their properties were investigated (secondary structure, liquid crystallinity, etc.). The enantiomers of isopinocampheol and β-pinene were used as model analytes for the study of enantiodiscrimination. Additionally, the usage of ¹ H-¹ H-RDCs to improve the alignment tensor quality is demonstrated.