A Dual-Responsive Hyperbranched Supramolcular Polymer Constructed By Cooperative Host-Guest Recognition And Hydrogen-Bond Interactions

Pillararenes（PAs）are a kind of novel macrocyclic host molecule with highly symmetric structures.Its cavity can bind a variety of guest molecules.There are many reports on the construction of supramolecular polymers based on the pillararenes.Because of the reversibility of non-covalent bond interactions,supramolecular polymer systems tend to exhibit different responses to external stimuli.In this dissertation,the investigations on pillararenes and supramolecular polymerization based on pillararenes were summarized.As we know,the non-covalent bond interactions of supramolecular polymers contain multiple hydrogen bonds,host-guest,metal coordination andπ-πstacking.In constructing supramolecular polymers,these interactions worked in a single,orthogonal,or synergistic manner.The cooperative supramolecular polymerization based on pillararenes has not been reported.As we know,cooperative non-covalent interactions are very important in biosystems and functional supramolecular systems.So we designed and synthesized a triangular molecule H₃ containing three adenine mono-functionalized pillar[5]erene molecules H₃ and a guest molecule G containing a pyrimidine base.The structures of the compounds were characterized by ¹H NMR,¹³C NMR,HRMS or MALDI-TOF-MS.Finally,the hyperbranched supramolecular polymer HSP-H₃G system was formed from the self-assembly between the H₃ and the G through the cooperative hydrogen bond,π-πstacking and host-guest interactions.¹H NMR titration experiments,two dimensional diffusion-ordered NMR experiments,viscosity measurements,and scanning electron microscope experiments were performed to determine the formation of HSP-H₃G system.The supramolecular polymer showed a dual stimulus response both to heat and acid/base.This is the first report of a pillar[5]erene hyperbranched supramolecular polymer system constructed by cooperative interaction.Our research provides a new idea for constructing supramolecular polymers.Since the supramolecular polymer has acid/base and heat/cold stimuli responsiveness,the present research provides a material basis for the development of responsive smart materials.