A dynamic NMR study of self-inclusion of a pendant group in amphiphilic 6-thiophenyl-6-deoxycyclodextrins

The dynamic stereochemistry of amphiphilic derivatives of alpha-, beta-, and gamma-cyclodextrins (1-3) has been investigated by means of variable temperature H-1 and C-13 NMR spectroscopy in DMF-d(7) solutions. The most significant spectral changes were detected for the smallest hexakis(6-thiophenyl-6-deoxy)-alpha-cyclodextrin (1) and they decrease with the increase of the macrocycle size. On the basis of ROESY measurements, these changes reflecting restricted movements of thiophenyl groups upon the temperature decrease were interpreted in terms of self-inclusion of at least one thiophenyl group. Molecular modeling of these compounds is consistent with these findings. (C) 2000 Elsevier Science B.V. All rights reserved.