Synthesis and Molecular Recognition Properties of a β-Cyclodextrin Tetramer

Article abstract of DOI:10.1021/jo00127a040

The synthesis and binding properties of a cyclodextrin tetramer are described.This species is composed of four individual cyclodextrin subunits covalently appended to a central aromatic core.The tetramer is prepared from β-cyclodextrin in five steps in an overall 14percent yield.We have performed a preliminary survey of the binding properties of this species.The structure of tetramer-tetraarylporphyrin complexes was examined by both NMR and mass spectrometry.The results are consistent with a 1:1 stoichiometry in which the aromatic substituents of the porphyrin moiety are incorporated into the individual cyclodextrin subunits of the tetramer.The cyclodextrin tetramer exhibits a high affinity for both tetraarylporphyrins and metalloporphyrins, with binding constants as large as 1E8 M^-1.Finally, we have compared and contrasted the behavior of the tetrameric species with that of two related cyclodextrin dimers.While all of these hosts bind both porphyrins and metalloporphyrins, the tetramer exhibits a special affinity for those guests that contain a neutral inner porphyrin core.