Sonogashira Couplings on the Surface of Montmorillonite-Supported Pd/Cu Nanoalloys
Sonogashira Couplings on the Surface of Montmorillonite-Supported Pd/Cu Nanoalloys
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蒙脱石负载 Pd/Cu 纳米合金表面的 Sonogashira 耦合
DOI：
10.1021/am505798y
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发表时间：
2014
影响因子：
9.5
通讯作者：
Gao Ziwei
中科院分区：
文献类型：
--
作者：
Xu Wei;Sun Huaming;Yu Bo;Zhang Guofang;Zhang Weiqiang;Gao Ziwei
为了探索钯催化Sonogashira偶联反应的真实特性，制备了蒙脱土（MMT@M，M = Pd，Cu，Fe，Ni）负载的过渡金属纳米粒子，并对其进行了表征和评价。在所有的MMT@M催化剂中，MMT@Pd/Cu表现出最高的活性，并成功地将其推广到20个实例，产率为57%-97%。MMT@Pd/Cu的形貌表征表明，结晶的Pd/Cu颗粒以纳米合金的形式分散在MMT层上，粒径在10 ~ 11 nm之间。用CO作分子探针的原位红外分析和XPS表征发现，Pd/Cu颗粒表面同时存在Pd（0）和Cu（I）两种催化活性位。对MMT@M的催化活性进行了研究，发现Pd/Cu催化剂体系只有在纳米合金状态下才表现出较高的催化活性。因此，Pd/Cu纳米合金被确定为催化剂，其表面之间的原子间Pd/Cu金属转移被认为是负责其协同活性。
To explore the true identity of palladium-catalyzed Sonogashira coupling reaction, montmorillonite (MMT)-supported transition metal nanoparticles (MMT@M, M = Pd, Cu, Fe, and Ni) were prepared, characterized, and evaluated systematically. Among all MMT@M catalysts, MMT@Pd/Cu showed the highest activity, and it was successfully extended to 20 examples with 57%–97% yields. The morphology characterization of MMT@Pd/Cu revealed that the crystalline bimetallic particles were dispersed on a MMT layer as nanoalloy with diameters ranged from 10 to 11 nm. In situ IR analysis using CO as molecular probe and XPS characterization found that the surface of Pd/Cu particles consisted of both catalytic active sites of Pd(0) and Cu(I). The experiments on the catalytic activities of MMT@M found that Pd/Cu catalyst system exhibited high activity only in nanoalloy form. Therefore, the Pd/Cu nanoalloy was identified as catalyst, on which the interatom Pd/Cu transmetalation between surfaces was proposed to be responsible for its synergistic activity.