Construction of supramolecular structures from cyclodextrins and polymers

Cyclodextrins (CDs) have been found to form inclusion complexes with various polymers with high specificity to give stoichiometric compounds in crystalline states. In these complexes, polymer chains were threaded into cyclodextrins and recognized by the host. For example, alpha-cyclodextrin (alpha-CD) formed complexes with poly(ethylene glycol) (PEG) of molecular weight higher than 200, although beta-CD did not form complexes with PEG of any molecular weight. However, beta-CD formed complexes with poly(propylene glycol) (PPG) of various molecular weights with which alpha-CD did not form complexes. gamma-CD formed complexes with poly(methyl vinyl ether) (PMVE), though alpha- and beta-CD did not form complexes with PMVE. alpha-CD formed complexes with oligoethylene, but only gamma-CD formed complexes with polyisobutylene of molecular weight over 500. The structures and properties of the complexes have been studied by spectroscopic methods. Polyrotaxanes in which many CDs are threaded on a single chain were prepared by capping the chain ends with bulky groups. Copyright (C) 1997 Elsevier Science Ltd. All rights reserved.