AbstractPoly(N-isopropylacrylamide)-based hydrogel particles (GPs) with different sized hydrogel networks were developed and used to confine a palladium (Pd) catalyst. The size of the gel network was tuned by varying the feed ratio of the cross-linking monomer. Nanosized-Pd(0) was loaded into the GPs, which contain a tertiary-amine ligand, via Pd-ion adsorption and subsequent reduction. The Pd-loaded GPs were used as the catalyst for a Suzuki coupling reaction between phenylboronic acid and 4-bromobenzoic acid in water at 30 °C. Due to the hydrophilic reaction platform provided by the hydrogel matrix of the GPs, the catalytic efficiencies of Pd-loaded GPs were significantly higher than those of commercially available Pd-loaded supports. Notably, the Pd-loaded GPs with the smallest gel networks were highly durable for Suzuki coupling reactions. It is plausible that the smaller network minimized or prevented the enlargement of Pd(0) during the catalytic cycle. The facile synthesis of the GPs, environmentally benign catalytic system, and high catalytic durability and activity of these Pd-loaded GPs are all important factors for the industrial application of these materials.A palladium (Pd) was confined within poly(N-isopropylacrylamide)-based hydrogel particles (GPs) with different sized hydrogel network. Nanosized Pd was loaded in the GPs via ligation to tertiary amine group in the GPs. The size of gel network was tuned varying the feed ratio of crosslinker. The catalytic efficacies of Pd-loaded GPs were significantly higher than those of commercially available Pd-loaded supports in Suzuki coupling reaction under aqueous condition. Using the smallest gel network, Pd-loaded GPs achieved the highest turnover number for the catalytic reaction, owing to protection of Pd from aggregation.

中文翻译：

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钯限制聚合物颗粒的尺寸调节水凝胶网络：一种在环境温度下在水中进行铃木偶联反应的高活性和耐用催化剂

摘要 开发了具有不同尺寸水凝胶网络的聚（N-异丙基丙烯酰胺）基水凝胶颗粒（GPs），并将其用于限制钯（Pd）催化剂。通过改变交联单体的进料比来调整凝胶网络的大小。通过 Pd 离子吸附和随后的还原，将纳米尺寸的 Pd(0) 加载到含有叔胺配体的 GP 中。负载Pd的GPs被用作30℃下苯基硼酸和4-溴苯甲酸在水中进行Suzuki偶联反应的催化剂。由于GPs的水凝胶基质提供了亲水反应平台，负载Pd的GPs的催化效率明显高于市售的负载Pd载体。值得注意的是，具有最小凝胶网络的负载 Pd GP 对于 Suzuki 偶联反应具有高度的耐用性。较小的网络在催化循环期间最小化或阻止了 Pd(0) 的增大是合理的。GPs 的简便合成、环境友好的催化体系以及这些负载 Pd 的 GPs 的高催化耐久性和活性都是这些材料工业应用的重要因素。 钯（Pd）被限制在聚（N-异丙基丙烯酰胺）中基于不同尺寸水凝胶网络的水凝胶颗粒（GPs）。通过连接到 GP 中的叔胺基团，将纳米尺寸的 Pd 加载到 GP 中。通过改变交联剂的进料比来调整凝胶网络的大小。在水性条件下的 Suzuki 偶联反应中，负载 Pd 的 GPs 的催化效率显着高于市售的负载 Pd 载体。使用最小的凝胶网络，