Designing an "a-ring-with-branches" polymer topology by electrostatic self-assembly and covalent fixation with interiorly functionalized telechelics having cyclic ammonium groups

A novel and unusual polymer topology, i.e. a-ring-with-two-branches, has be en constructed efficiently by making use of an interiorly functionalized po ly(tetrahydrofuran) (poly(THF)) having two pyrrolidinium groups. The dicarb oxylate counterion, i.e. terephthalate, was then introduced by an ion-excha nge reaction of the interiorly located pyrrolidinium group. Subsequent heat treatment under appropriate, dilution caused an efficient polymer cyclizat ion to produced an a-ring-with-two-branches polymer topology in high yield through the selective and quantitative ring-opening of the pyrrolidinium gr oups by the dicarboxylate counterion.