Chemically cross-linked polyacrylonitrile. A DMSO compatible NMR alignment medium for measurement of residual dipolar couplings and residual chemical shift anisotropies

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

“…The first one consists of mechanically strained gels, either stretchable [9,10] or compressible. [11,12] The second family, to which the aligning medium presented in this article belongs, is formed by a nowadays large variety of lyotropic liquids crystals (LLCs) compatible not only with water but also organic solvents. 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.…”

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

“…Similar to gibberellin ( 1 ), a low Q factor of 0.09 was obtained for triptolide ( 2 ) (Figure S15). To test the possibility of using the acquired RDC data for determining the relative configuration, we fitted experimental RDCs of α‐santonin to the DFT‐optimized structures of eight possible diastereoisomers (Figure S17). As shown in Figure , the correct stereoisomer SSSS shows the lowest Q factor of 0.06, whereas the other configurations have significantly larger Q factors ranging from 0.11 to 0.19.…”

Elucidating natural product structures using a robust measurement of carbon residual chemical shift anisotropy combined with DFT

“…[12,16] Residual dipolar couplings (RDCs) and residual chemical shift anisotropies (RCSAs) are two main classes of anisotropic NMR parameters utilized in small molecule and biomolecules. Although RDCs have been successfully used to determine configuration [15,[17][18][19][20][21] conformation [15] and the constitution in some cases, [22] RCSAs were occasionally applied in biomolecules. [23] Recently, a new computational technique for I > 1/2 deuterium nucleus using another anisotropic parameter residual quadrupolar coupling has been introduced to both elucidate the 3D structure of chiral and achiral organic molecules.…”

“…[13,14,33] These developments render RCSA analysis a powerful tool in the structure elucidation process, and recently, they were used to determine configurations. [13,14,19,[34][35][36][37] As noted above, DFT-computed CSA tensors are required for the interpretation of RCSA data. [12,13] Because it is problematic to measure them employing solid-state NMR for carbons with smaller CSAs, alternate means of computing CSA tensors using computational chemistry becomes mandatory.…”