Measurement of Residual Dipolar Couplings of Organic Molecules in Multiple Solvent Systems Using a Liquid‐Crystalline‐Based Medium

• Published in: Angewandte Chemie 2020-09, Vol.132 (39), p.17245-17251
• Main Authors: Qin, Si‐Yong, Jiang, Yan, Sun, Han, Liu, Han, Zhang, Ai‐Qing, Lei, Xinxiang
• Format: Article
• Language: English
• Subjects: alignment media; Anisotropy; Chemistry; Coupling (molecular); Couplings; Dipole interactions; lyotropic liquid crystals; NMR; NMR spectroscopy; Nuclear magnetic resonance; Organic chemistry; Parameter robustness; peptide self-assembly; residual dipolar coupling; Solvents
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202007243

Residual dipolar coupling (RDC), a robust anisotropic NMR parameter for structural elucidation of organic molecules, is only accessible in an anisotropic environment. Herein, we introduce a novel alignment medium based on the molecular self‐assembly of oligopeptide amphiphile (OPA). This medium is compatible with different intermediate and polar solvent systems, such as CD3OD, [D6]DMSO, and D2O. The preparation of the OPA‐based medium is simple and rapid, while only very weak background signals were observed from OPAs. Furthermore, we show that the purity of OPA has only a minor influence on the quality of the RDC data. These advantages allow RDC measurements of organic molecules with different polarities and solubilities with high efficiency and accuracy. Hat‐trick: An alignment medium compatible with multiple solvents ([D6]DMSO, CD3OD, D2O) is fabricated by molecular self‐assembly. The facile fabrication of the three‐in‐one system combined with its negligible background signals and without strict purity requirements enables efficient and accurate RDC measurements of organic molecules with different polarities and solubilities.