You Bingxin, Tian Yuyang, Wang Baolin, Zhu Guangshan
Key Laboratory of Polyoxometalate and Reticular Material Chemistry of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China.
Key Laboratory of Polyoxometalate and Reticular Material Chemistry of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China.
J Colloid Interface Sci. 2022 Dec 15;628(Pt A):1023-1032. doi: 10.1016/j.jcis.2022.08.026. Epub 2022 Aug 8.
The development of efficient and recyclable heterogeneous Pd catalysts is an area of continuing attention due to their critical applications in organic synthesis and pharmaceutical production. In this study, two novel heterogeneous catalysts Pd@PAF-182 and Pd@PAF-183 were prepared by the immobilization/NaBH reduction of PdCl on hydrophilic cationic porous aromatic frameworks (PAF-182 and PAF-183), which were synthesized via a Yamamoto-type Ullmann coupling reaction from the corresponding aryl quaternary phosphonium salt monomer. Characterization by powder X-ray diffraction (PXRD), solid-state Cross-Polarization Magic-Angle-Spinning Nuclear Magnetic Resonance (CP/MAS NMR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) established the structures of the as-prepared catalysts. Inductively coupled plasma atomic emission spectrometry (ICP-AES) detection showed that the loading of Pd nanoparticles (Pd NPs) were 29.4 wt% for Pd@PAF-182 and 37.5 wt% for Pd@PAF-183, much higher than those of similar porous materials. Evaluation of the catalytic activity of the Pd@PAFs using Suzuki coupling as the model reaction demonstrated that as little as 0.12 mol% of Pd NPs could catalyze the Suzuki coupling with high efficiency, achieving yields up to 99% at 80 °C in 8 h. Recycling experiments also suggested that Pd@PAF-182 and Pd@PAF-183 maintained high catalytic activity with negligible leaching of Pd NPs after five cycles.
高效且可回收的多相钯催化剂的开发一直备受关注，因为它们在有机合成和药物生产中具有关键应用。在本研究中，通过将PdCl固定在亲水性阳离子多孔芳香框架（PAF - 182和PAF - 183）上并进行硼氢化钠还原，制备了两种新型多相催化剂Pd@PAF - 182和Pd@PAF - 183，这些框架是通过山本型乌尔曼偶联反应由相应的芳基季鏻盐单体合成的。通过粉末X射线衍射（PXRD）、固态交叉极化魔角旋转核磁共振（CP/MAS NMR）、X射线光电子能谱（XPS）、扫描电子显微镜（SEM）和透射电子显微镜（TEM）对所制备的催化剂进行表征，确定了其结构。电感耦合等离子体原子发射光谱（ICP - AES）检测表明，Pd@PAF - 182中钯纳米颗粒（Pd NPs）的负载量为29.4 wt%，Pd@PAF - 183中为37.5 wt%，远高于类似多孔材料。以铃木偶联作为模型反应对Pd@PAFs的催化活性进行评估表明，低至0.12 mol%的Pd NPs就能高效催化铃木偶联反应，在80°C下8小时内产率可达99%。回收实验还表明，Pd@PAF - 182和Pd@PAF - 1⑧3在五个循环后仍保持高催化活性，Pd NPs的浸出可忽略不计。
