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Ji-Qiang Fan Dr. Ying Yang Cheng-Bo Tao Prof. Man-Bo Li 《Angewandte Chemie (International ed. in English)》2023,62(6):e202215741
A gold nanocluster Au17Cd2(PNP)2(SR)12 (PNP=2,6-bis(diphenylphosphinomethyl)pyridine, SR=4-MeOPhS) consisting of an icosahedral Au13 kernel, two Au2CdS6 staple motifs, and two PNP pincer ligands has been designed, synthesized and well characterized. This cadmium and PNP pincer ligand co-modified gold nanocluster showed high catalytic efficiency in the KA2 reaction, featuring high TON, mild reaction conditions, broad substrate scope as well as catalyst recyclability. Comparison of the catalytic performance between Au17Cd2(PNP)2(SR)12 and the structurally similar single cadmium (or PNP) modified gold nanoclusters demonstrates that the co-existence of the cadmium and PNP on the surface is crucial for the high catalytic activity of the gold nanocluster. This work would be enlightening for developing efficient catalysts for cascade reactions and discovering the catalytic potential of metal nanoclusters in organic transformations. 相似文献
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Green bio‐based synthesis of Fe2O3@SiO2‐IL/Ag hollow spheres and their catalytic utility for ultrasonic‐assisted synthesis of propargylamines and benzo[b]furans
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A novel magnetic hybrid system containing nano‐magnetic Fe2O3 hollow spheres, silica shell, [pmim]Cl ionic liquid and silver nanoparticles was synthesized and characterized. The silver nanoparticles were prepared via biosynthesis using Achillea millefolium flower as reducing and stabilizing agent. The hybrid system was successfully used as an efficient and reusable catalyst for promoting green ultrasonic‐assisted A3 and KA2 coupling reactions as well as benzo[b]furan synthesis. It was found that decoration of the magnetic core with non‐magnetic moieties decreased the maximum saturation magnetization. However, the catalyst was still superparamagnetic and could be simply separated from the reaction mixture using an external magnet. The heterogeneous nature of the catalyst was also confirmed by studying its reusability and stability and the leaching of silver. Use of aqueous media, high yields, short reaction times, broad substrate tolerance and low required amount of catalyst are the merits of this protocol. 相似文献
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朱颖达 《宁波大学学报(理工版)》2007,20(1):59-61
KA3525是PWM控制器件,利用其输出方波脉冲激励逆变器推挽电路的工作原理,使输出功率器件工作在开关状态,从而达到高效的目的.从介绍逆变电路工作原理和充、放电控制电路的工作模式出发,对逆变器高效原理进行了探讨.实验证明:该电路工作效率高、实用、可靠,使用方便、灵活,可以大大延长蓄电池的使用时间和照明时间,有较大实用价值. 相似文献