A [2]Rotaxane Capped by a Cyclodextrin and a Guest:Formation of Supramolecular [2]Rotaxane Polymer

摘要

Recently,much attention has been focused on interlocked molecules,such as rotaxanes,catenanes,and knots,because of their unique structures and properties.Cyclodextrins (CDs) have been extensively used as a rotor of rotaxanes and catenanes.However,[2]rotaxanes using CD as a stopper have not been reported.If a [2Jrotaxane containing a CD at one end of the axle and a guest at the other end is available,intermolecular complexes will be formed to give Supramolecular polymers because a rotaxane structure is rigid enough to prevent intramolecular complexation (Chart 1).Now,we have prepared a [2]rotaxane containing alpha-CD as a rotor,beta-CD as a stopper,and a trinitrophenyl group as an another stopper (Scheme 1).We found that a beta-CD stopper forms intermolecular complexes with a guest stopper of another [2]-rotaxane to give Supramolecular [2]rotaxane polymers in which alpha-CD and beta-CD line up in an alternating manner.