Polymer gel catalysts are attractive due not only to their recyclability but also to the unique reaction environment in the internal space of the network structure. Appropriate design of the nanostructure around catalytically active sites in the gel network is particularly important. In this work, we aimed to control the activity and selectivity of the iridium-catalyzed N-alkylation of amine substrates with alcohols by incorporating an iridium complex into the crosslinked domain (CD) nanostructure of amphiphilic gels. A variety of gels with homogeneously dispersed CD structures containing iridium complexes with various crosslinking densities were prepared by the reversible addition–fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide and an iridium complex monomer using a poly(N,N-dimethylacrylamide) macro-chain transfer agent (CTA) in the presence of a divinyl crosslinker. The resulting CD gel showed catalytic activity for the N-alkylation of aniline with benzyl alcohol, and importantly, the steric effect of the CD structure allowed the selective formation of a secondary amine product by controlling the access of the substrate to the iridium complex. Thus, we demonstrated selectivity control through the design of the nanospace surrounding the catalytic center using a nanostructured amphiphilic gel.

聚合物凝胶催化剂的吸引力不仅在于其可回收性，还在于网络结构内部空间独特的反应环境。凝胶网络中催化活性位点周围纳米结构的适当设计尤为重要。在这项工作中，我们的目的是通过将铱络合物掺入两亲性凝胶的交联域（CD）纳米结构中来控制铱催化的胺底物与醇的N-烷基化反应的活性和选择性。采用聚( N,N-二甲基丙烯酰胺)大分子，通过N-异丙基丙烯酰胺和铱络合物单体的可逆加成-断裂链转移(RAFT)聚合，制备了各种具有均匀分散的CD结构的凝胶，其中含有不同交联密度的铱络合物。 -二乙烯基交联剂存在下的链转移剂(CTA)。所得的CD凝胶显示出对苯胺与苯甲醇的N-烷基化的催化活性，并且重要的是，CD结构的空间效应允许通过控制底物与铱络合物的接触来选择性地形成仲胺产物。因此，我们通过使用纳米结构两亲性凝胶设计催化中心周围的纳米空间来证明选择性控制。