Macromolecules, Vol.49, No.11, 4076-4087, 2016
Construction of Hybrid-Multicyclic Polymer Topologies Composed of Dicyclic Structure Units by Means of An ESA-CF/Click-Linking Protocol
A series of tri- and tetracyclic polymer topologies, composed of an elementary dicyclic unit of either theta-, eight- or manacle-forms, have been constructed by means of an ESA-CF (electrostatic self-assembly and covalent fixation) protocol in conjunction with an alkyne-azide click linking technique. Thus, a theta-shaped poly(THF) precursor having an alkyne group at the junction position (Ic) has newly been prepared by an ESA-CF process using an assembly (1b/2d), composed of a star poly(THF) having N-phenylpyrrolidinium salt groups carrying a counteranion of a trifunctional carboxylate having an alkyne group. In addition, monocyclic polymer precursors having an azide group (Ha) as well as linear-cyclic (tadpole) (I1b) and linear-dicyclic (twin-head tadpole) (IIc) polymer precursors, both having an azide group at the tail-end position, have been prepared through the tandem click reaction of the respective monocyclic and dicyclic (eight-form) precursors having an alkyne group (Ia and Ib, respectively) with a linear asymmetric telechelic poly(THF) having an azide and an hydroxyl groups (1d), followed by the esterification with 4-azidobenzoic acid. A variety of hybrid-tricyclic polymer topologies (IIIa, Mb, and Inc) composed of a dicyclic (theta- or eight-shaped) and a monocyclic (simple ring or tadpole-shaped) units, and moreover, an unprecedented hybrid-tetracyclic topology composed of all three elementary dicyclic units of theta-, eight- and manacle-forms (IVb), in addition to a double-theta topology (IVa) have been constructed through the effective click-linking of complementarily reactive kyklo-telechelic precursors.