Formation of a Supramolecular Hyperbranched Polymer from Self-Organization of an AB₂ Monomer Containing a Crown Ether and Two Paraquat Moieties

Abstract

An AB2 monomer containing a bis(m-phenylene)-32-crown-10 and two paraquat moieties was designed and prepared. It self-organized to form a supramolecular hyperbranched polymer in solution.

Responsive Supramolecular Gels Constructed by Crown Ether Based Molecular Recognition

“…[7] As the first artificially synthesized host molecules, crown ethers can bind metal and organic ammonium cations, if these guest molecules fit into the macrocyclic cavities.[8] Previously, crown ether-based molecular recognition has facilitated the synthesis of a variety of supramolecular polymers with chain topologies varying from linear (AB, ABA, alternating), [9] star, [10] cross-linked, [11] hyperbranched, [12] and dendronized polymers, [13] as well as dendrimers.[14] Notably, reports concerning crown ether-based supramolecular gels are relatively rare, [15] partially owing to synthetic difficulties encountered in the preparation of welldefined polymer precursors embedded with multiple crown ether hosts at predetermined positions.Herein we report the fabrication of responsive supramolecular gels on the basis of reversible molecular recognition between dibenzo[24]crown-8 (DB24C8) and dibenzylammonium salt (DBAS) moieties, using biodegradable poly(e-caprolactone) (PCL) segments as the scaffold (Scheme 1). DB24C8-terminated four-arm star PCL (fourarm star PCL-DB24C8) and DBAS-terminated two-arm PCL (two-arm PCL-DBAS) were synthesized by a combination of ring-opening polymerization (ROP) and click reaction.…”

Assembly of a Self‐Complementary Monomer: Formation of Supramolecular Polymer Networks and Responsive Gels

“…Consequently, chemists have developed a variety of strategies for constructing supramolecular polymers over the past years, [2,3] in which host-guest interaction [4] has become one of the most important and convenient approaches. In particular, crown ether based molecular recognition has been successfully utilized in the construction of supramolecular polymers with linear, [5] star, [6] hyperbranched, [7] and dendronized [8] topologic structures. Some of the supramolecular polymers with specific structures also form supramolecular gels, [9] which have received significant and current attention because of their wide potential application in materials science, drug delivery, and chemical sensors.…”

Negatively charged crown ethers for binding paraquat in water

“…Paraquat (N,N′-dimethyl-4,4′-bipyridinium) and its derivatives have been widely used as guests in supramolecular chemistry to construct numerous host-guest complexes [1][2][3][4][5]. Paraquat is not only a -electron acceptor [6] but also an effective and nonselective herbicide used in more than 100 countries [7][8][9][10].…”