Synthesis And Catalytic Performance Of Supermolecule-based Covalent Organic Polymers/Metal Nanoparticle Composites

Organic polymers containing supramolecular skeleton represent a novel type of materials that are covalently connected into network by supermolecules and a variety of small molecular fragments.This class of materials combined the merits of polymers and supramolecular chemistry,not only have controllable structure,adjustable functionality and high stability,but also possess unique responsiveness toward guest molecules.They are highly possible to play important roles in the fields of adsorption,separation,energy resources,sensors and heterogeneous catalysis.In this paper,two types of supramolecular covalent organic polymer composite materials are synthesized fromβ-cyclodextrin and organic cage,respectively,and their catalytic properties are studied.The content is as follows:（1）β-CD based polymer networks（β-CDP-N andβ-CDP-C）with a guest-responsive were successfully constructed fromβ-CD via a facile one-step nucleophilic substitution reaction.Usingβ-CD based polymer networks as support materials,Au@β-CDPs composite materials were prepared by impregnation and reduction methods.The as-prepared materials exhibited excellent catalytic activities in the catalytic reduction of 4-nitrophenol.Among them,the kinetic rate constant（Kapp）value of Au@β-CDP-N is 14.15×10^-2s^-1,which is higher than all previously reported Au NPs catalysts with solid supports.The unique“guest-responsive property”ofβ-CD based polymer improved the mass transfer efficiency of the reaction,which is a significant factor resulted to the excellent catalytic performance of the material.Moreover,Au@β-CDP-N exhibited excellent recyclability and maintained its high catalytic efficiency after seven cycles.（2）In this work,imine molecular cage（Cage 1）was initially prepared from tris（2-aminoethyl）amine and p-alkynylisophthalide via imine condensation reaction,then it was reduced by sodium borohydride to give the corresponding amine cage（CageA）.Using CageA as the building block,a cage-based organic polymer/metal nanoparticle composite（Pd@COP-A）was prepared through the strategy of pre-coordination and then self-polymerization.The composite showed high catalytic activity and excellent recyclability in Suzuki-Miyaura coupling reaction.