Polyaspartates as Thermoresponsive Enantiodifferentiating Helically Chiral Alignment Media for Anisotropic NMR Spectroscopy.

Lyotropic liquid crystalline phases of poly-β-phenethylaspartates are presented as new helically chiral enantiodifferentiating alignment media with thermoresponsive properties. In addition to displaying the highest enantiodifferentiation observed for homopolypeptides, the alignment media undergo a temperature induced helix reversal without perturbing the nematic phase. This offers the opportunity to measure residual dipolar couplings (RDCs) in high and low temperature helix conformation (P- and M-helix) in one polymer. Thus different mean orientations of a chiral analyte can be determined within the same sample. Furthermore, we investigated whether the resulting media are diastereomeric and whether we are able to obtain information about the alignment process.