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

Abstract

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.

A Lyotropic Liquid Crystal from a Flexible Oligopeptide Amphiphile in Dimethyl Sulfoxide

“…Recently, RDCs have attracted great attention in the field of liquid-state NMR spectroscopy since they can provide the stereochemical information of molecules. − The accurate acquirement of RDCs has been achieved in different aligned media. ,− To investigate the applicability of OPA LC as an aligned medium for RDC acquisition, aromatic estrone was first employed as the model molecule. As shown in Figure S12, the 2 H NMR spectrum of the anisotropic OPA LC (4 wt % in DMSO- d 6 ) containing 10.0 mg of estrone showed an RQC of 20.42 Hz, suggesting its compatibility with estrone.…”

In Situ Visualization of the Structural Evolution and Alignment of Lyotropic Liquid Crystals in Confined Flow

“…Such properties are of high interest in applications such as scaffolds for catalysis and separation, [ 17 ] templating, [ 18 ] encapsulation of molecules as drug delivery agents and nanocarriers, [ 19,20 ] or as media to obtain structural data of molecules. [ 21,22 ]…”

Single experiment measurement of residual dipolar couplings in aqueous solution using a biphasic bisperylene imide chromonic liquid crystal

“…Recently studied or developed aligning media LLC phases are based on mesogens of different nature such as helical stiff polymers (polyacetylenes [13,14] polyaspartates, [15] polyisocyanides, [16] and polypeptides [14,17,18] ), graphene-oxide systems, [19,20] cellulose nanocrystals, [21] or oligo peptides. [22,23] A few of these systems present peculiar properties which allow the obtention of anisotropic parameters in a single experiment. One of these systems are poly-HEMA DMSO-compatible compressible gels.…”

“…Recently studied or developed aligning media LLC phases are based on mesogens of different nature such as helical stiff polymers (polyacetylenes [ 13,14 ] polyaspartates, [ 15 ] polyisocyanides, [ 16 ] and polypeptides [ 14,17,18 ] ), graphene‐oxide systems, [ 19,20 ] cellulose nanocrystals, [ 21 ] or oligo peptides. [ 22,23 ]…”