Molecular self-assembly behavior of mono[6-0-6(4-carboxyl-phenyl)]-β-CD in solution and solid state

Abstract

A novel modified cyclodextrin, mono[6-O-6-(4-

carboxyl-phenyl)]-b -CD (1), has been synthesized by the

reaction of mono[6-(p-toluenesulfonyl)]- b -CD with 4-hydroxybenzoate,

and its molecular self-assembly behavior in both

solution and solid state was studied by means of

crystallography, NMR spectroscopy and microcalorimetry.

The results indicate that the bezoic acid groups are

successively penetrated intermolecularly into the adjacent

b -CD cavities to form helical columnar supramolecules in the

solid state. As compared with crystal, the similar

self-assembly behavior of 1 in aqueous solution has also been

confirmed by the 1H ROESY spectroscopy.

Thermodynamically, the formation of polymeric

supramolecules by modified CD in aqueous solution is mainly

driven by entropy changes.