The use of a lyotropic liquid-crystalline medium and residual dipolar coupling constants for determination of the spatial structure of thiacalix[4]arenes in solutions

The possibility of using an approach for the elucidation of the spatial structure of functionalized thiacalix[4]arenes based on the determination the residual dipolar coupling constants between the H-1 and C-13 nuclei separated by one chemical bond (D-1(CH)) in lyotropic liquid-crystalline media (poly-gamma-benzyl-(L)-glutamate and CDCl3) is demonstrated for the first time. This approach was used to distinguish between the cone and 1,3-alternate conformations of 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(2-oxopropyloxy)-2,8,14,20-tetrathia-calix[4]arene. The results were confirmed by the data from 2D NMR (H-1-H-1) NOESY experiments for these compounds in an isotropic solvent (CDCl3).