Macromolecular recognition: New cyclodextrin polyrotaxanes and molecular tubes

It was found that cyclodextrins (CDs, alpha-, beta- and gamma-CD) formed in clusion complexes not only with hydrophilic polymers, such as poly (ethylen e glycol) (PEG), poly (propylene glycol) (PPG) and poly (methyl vinyl ether ) (PMVE), but also with hydrophobic polymers, such as oligoethylene, polypr opylene, polyisobutylene and polyesters. alpha-CD formed complexes with oli goethylene, although beta- and gamma-CD did not under the same conditions. gamma-CD formed complexes with polyisobutylene in high yield, although alph a-CD did not. There is a good correlation between the sizes of cavities of cyclodextrins and the cross-sectional areas of the polymers. The polymer co mplexes are crystalline and polyrotaxane-type inclusion complexes. It was a lso found that cationic polymers such as viologen polymers and polyionenes form complexes with cyclodextrins to give soluble complexes in water. New p olyrotaxanes in which many CDs are threaded on to polymer chains have been prepared by capping both polymer ends by large stoppers. (C) 1999 John Wile y & Sons, Ltd.