A highly water-dispersible/magnetically separable palladium catalyst based on a Fe3O4@SiO2 anchored TEG-imidazolium ionic liquid for the Suzuki-Miyaura coupling reaction in water
A highly water-dispersible/magnetically separable palladium catalyst based on a Fe3O4@SiO2 anchored TEG-imidazolium ionic liquid for the Suzuki-Miyaura coupling reaction in water
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DOI：
10.1039/c3gc42311e
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发表时间：
2014-01-01
期刊：
影响因子：
9.8
通讯作者：
Vali, Hojatollah
中科院分区：
文献类型：
--
作者：
Karimi, Babak;Mansouri, Fariborz;Vali, Hojatollah
通过在二氧化硅包覆的氧化铁纳米粒子表面锚定含有三甘醇基团的咪唑类离子液体，制备了一种新型的离子液体功能化磁性纳米粒子。该材料被证明是一个有效的主机的Pd催化剂的固定化，通过随后的简单的离子交换过程，得到一个高度的水分散性，活性和磁性可回收的Pd催化剂（Mag-IL-Pd）在铃木宫浦偶联反应在水中。如此制备的催化剂显示出对具有挑战性的底物如杂芳基卤化物和邻位取代的芳基卤化物以及芳基氯化物的显著活性，使用非常低的Pd负载量，以优异的产率并表现出高TON。由于该催化剂在有机溶剂中的溶解度极低，回收的含催化剂的水相可以简单有效地连续使用10次而活性没有显著降低，并且在该方法结束时可以通过施加外部磁场容易地从水相中分离。这种具有可忽略的浸出的新颖的双重分离策略使得Mag-IL-Pd成为进行这种转化的生态友好和经济的催化剂。
A novel ionic liquid functionalized magnetic nanoparticle was prepared by anchoring an imidazolium ionic liquid bearing triethylene glycol moieties on the surface of silica-coated iron oxide nanoparticles. The material proved to be an effective host for the immobilization of a Pd catalyst through a subsequent simple ion-exchange process giving a highly water dispersible, active and yet magnetically recoverable Pd catalyst (Mag-IL-Pd) in the Suzuki-Miyaura coupling reaction in water. The as-prepared catalyst displayed remarkable activity toward challenging substrates such as heteroaryl halides and ortho-substituted aryl halides as well as aryl chlorides using very low Pd loading in excellent yields and demonstrating high TONs. Since the catalyst exhibited extremely low solubility in organic solvent, the recovered aqueous phase containing the catalyst can be simply and efficiently used in ten consecutive runs without significant decrease in activity and at the end of the process can be easily separated from the aqueous phase by applying an external magnetic field. This novel double-separation strategy with negligible leaching makes Mag-IL-Pd an eco-friendly and economical catalyst to perform this transformation.