Supramolecular Alternating Polymers Based on Calix[4]pyrrole and Pillar[5]arene Molecular Recognition

Supramolecular alternating polymers (SAPs) were constructed based on orthogonal interactions between an alkylnitrile-tethered calix[4]pyrrole and two different carboxylate-functionalized pillar[5]arene monomers possessing different chain lengths. Concurrent anion complexation and host-guest interactions were utilized by means of calix[4]pyrrole- and pillar[5]arene-based molecular recognitions. Characterization and multiresponsive behaviors of the resulting SAPs were characterized by means of a series of analyses, including various nuclear magnetic resonance techniques, viscosity measurements, and scanning electron microscopy. The resulting polymers were also applied to the fabrication of hierarchical materials with different dimensionalities. These materials include spherical aggregates with zero-dimensionality, fibers with one-dimensionality, two-dimensional microporous films, and finally three-dimensional materials. Current work represents the first example of SAPs based on calix[4]pyrrole and pillar[5]arene molecular recognition and is expected to be useful for designing and preparation of advanced, multicomponent synthetic self-assembled systems.