Soltani Siavash Salek, Taheri-Ledari Reza, Farnia S Morteza F, Maleki Ali, Foroumadi Alireza
School of Chemistry, College of Science, University of Tehran Tehran Iran
Catalysts and Organic Synthesis Research Laboratory, Department of Chemistry, Iran University of Science and Technology Tehran 16846-13114 Iran
RSC Adv. 2020 Jun 18;10(39):23359-23371. doi: 10.1039/d0ra04521g. eCollection 2020 Jun 16.
Herein, a novel high-performance heterogeneous catalytic system made of volcanic pumice magnetic particles (VPMP), cellulose (CLS) natural polymeric texture, and palladium nanoparticles (Pd NPs) is presented. The introduced VPMP@CLS-Pd composite has been designed based on the principles of green chemistry, and suitably applied in the Suzuki-Miyaura cross-coupling reactions, as an efficient heterogeneous catalytic system. Concisely, the inherent magnetic property of VPMP (30 emu g) provides a great possibility for separation of the catalyst particles from the reaction mixture with great ease. In addition, high heterogeneity and high structural stability are obtained by this composition resulting in remarkable recyclability (ten times successive use). As the main catalytic sites, palladium nanoparticles (Pd NPs) are finely distributed onto the VPMP@CLS structure. To catalyze the Suzuki-Miyaura cross-coupling reactions producing biphenyl pharmaceutical derivatives, the present Pd NPs were reduced from chemical state Pd to Pd. In this regard, a plausible mechanism is submitted in the context as well. As the main result of the performed analytical methods (including FT-IR, EDX, VSM, TGA, FESEM, TEM, BTE, and XPS), it is shown that the spherical-shaped nanoscale Pd particles have been well distributed onto the surfaces of the porous laminate-shaped VPMP. However, the novel designed VPMP@CLS-Pd catalyst is used for facilitating the synthetic reactions of biphenyls, and high reaction yields (∼98%) are obtained in a short reaction time (10 min) by using a small amount of catalytic system (0.01 g), under mild conditions (room temperature).
本文介绍了一种由火山浮石磁性颗粒（VPMP）、纤维素（CLS）天然聚合物结构和钯纳米颗粒（Pd NPs）组成的新型高性能多相催化体系。所引入的VPMP@CLS-Pd复合材料是基于绿色化学原理设计的，并作为一种高效的多相催化体系适用于铃木-宫浦交叉偶联反应。简而言之，VPMP（30 emu g）的固有磁性为轻松从反应混合物中分离催化剂颗粒提供了极大的可能性。此外，这种组成获得了高非均质性和高结构稳定性，从而具有显著的可回收性（连续使用十次）。作为主要催化位点，钯纳米颗粒（Pd NPs）精细地分布在VPMP@CLS结构上。为了催化生成联苯药物衍生物的铃木-宫浦交叉偶联反应，目前的Pd NPs从化学态Pd还原为Pd。在这方面，本文还提出了一种合理的机理。作为所进行的分析方法（包括傅里叶变换红外光谱、能谱分析、振动样品磁强计、热重分析、场发射扫描电子显微镜、透射电子显微镜、比表面积测定和X射线光电子能谱）的主要结果表明，球形纳米级Pd颗粒已很好地分布在多孔层状VPMP的表面。然而，新设计的VPMP@CLS-Pd催化剂用于促进联苯的合成反应，在温和条件（室温）下，使用少量催化体系（0.01 g），在短反应时间（10分钟）内可获得高反应产率（约98%）。
