A Supramolecular Triarm Star Polymer from a Homotritopic Tris(Crown Ether) Host and a Complementary Monotopic Paraquat-Terminated Polystyrene Guest by a Supramolecular Coupling Method

Abstract

The first supramolecular star polymer based on pseudorotaxane host-guest complexation was prepared from statistical complexation of a homotritopic tris(crown ether) host and monotopic paraquat-terminated polystyrene guest in solution. The formation of this supramolecular star polymer was confirmed by proton NMR characterization and viscosity studies.

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

“…Similarly, model molecule 2 was prepared in 95 % yield by the reaction of acid anhydride 7 and aniline. Model molecule 3 was conveniently obtained by the reaction of 7 and 14, followed the hydrolysis by aqueous HPF 6 . Compound 2 was designed to study its complexation with dibenzylammonium ions, and subsequently afforded a model system for further study of the assembly behavior of monomer 1.…”

“…Consequently, strong peaks at m/z 868.2 and 1538.5 for [2·4 2 À2 PF 6 À ] 2 + and [2·4ÀPF 6 À ] + , respectively, were found. Further support for the formation of the complex 2·4 2 came from its X-ray analysis (see the Experimental Section).…”

“…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.…”

Nitroxide: Anwendungen in der Synthese und in der Polymerchemie

“…Über NMP hergestellte Polystyrolarme konnten so mit dem Grundgerüst der Tri(kronenether)-Einheit verknüpft werden. [285] Auch Biohybridmaterialien wurden in Form von PeptidPolymer-oder Protein-Polymer-Konjugaten mit NMP erzeugt. [286] Kovalent an Peptide gebundene Alkoxyamine initiierten beispielsweise die kontrollierte radikalische Polymerisation von Acrylaten und Styrol.…”