文摘
A dicyclic, eight-shaped and a tricyclic, trefoil-shaped poly(THF) both having an alkyne group at the core position (II and III, respectively) have been introduced as versatile core-clickable kyklo-telechelic precursors. The prepolymer II has been prepared by an ESA-CF (electrostatic self-assembly and covalent fixation) process using an assembly (1a/2b), composed of two units of linear poly(THF) having N-phenylpyrrolidinium salt groups carrying one unit of a tetrafunctional carboxylate having an alkyne group as a counteranion. Alternatively, the prepolymer III has been produced through a click process using a cyclic poly(THF) precursor having an azide group (Ia), obtainable also by the ESA-CF technique, with a tripropargylated pentaerythritol derivative (2c) followed by the esterification with 4-pentynoic acid to introduce again an alkyne group. The subsequent click coupling reaction of II and III with a linear telechelic poly(THF) having azide groups (1b) afforded successfully novel tetra- and hexacyclic bridged-spiro hybrid polymer topologies, i.e., double-eight and double-trefoil constructions.