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

Abstract

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 1H and 13C nuclei separated by one chemical bond ( 1D CH) in lyotropic liquid-crystalline media (poly-γ-benzyl-L-glutamate and CDCl 3) 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-tetrathiacalix[4]arene. The results were confirmed by the data from 2D NMR ( 1H - 1H) NOESY experiments for these compounds in an isotropic solvent (CDCl 3).