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首页> 外文期刊>Organometallics >Importance of the Pd and Surrounding Sites in Hydrosilylation of Internal Alkynes by Palladium-Gold Alloy Catalyst
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Importance of the Pd and Surrounding Sites in Hydrosilylation of Internal Alkynes by Palladium-Gold Alloy Catalyst

机译：PD钯金合金催化剂对内部炔烃水溶液中Pd及周边地点的重要性

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摘要

Recently, the Pd-Au alloy catalyst has been developed for the hydrosilylation of internal alkynes as well as alpha,beta-unsaturated ketones under mild conditions. In this work, the mechanism of the hydrosilylation reaction of internal alkynes on the Pd-Au bimetallic cluster and the Pd-Au(111) alloy surface has been investigated by density functional theory calculations. The calculated energy profiles show that the reaction follows the Chalk-Harrod mechanism. The rate-determining step is the hydrometalation in the Pd-Au cluster while it is the Si-C reductive elimination in the Pd-Au(111) alloy surface. The Pd site acts as the adsorption site and the reactive center as observed in experiments. The surrounding Pd-Au bridge and Au sites are also relevant for the bond activation and accepting the substrates or intermediates during the reaction, which is characteristic in the Pd-Au alloy catalysts and not available in the homogeneous catalyst. The hydrosilylation reaction proceeds without too much high energy barriers and too stable intermediates in the Pd-Au alloy catalyst. The monometallic Au and Pd catalysts are not preferable because of the high energy barriers (Au) or too stable intermediates (Pd). The present picture of the relevance of the Pd atomic site and its surrounding Pd-Au bridge or Au sites will be useful for developing the alloy catalysts for the related catalytic reactions.
机译：最近，已经开发了PD-Au合金催化剂，用于在温和条件下为内部炔烃的氢化硅烷化以及α，β-不饱和酮。在这项工作中，通过密度泛函理论计算研究了内部炔醇内酯的液体溶液反应和PD-Au（111）合金表面的机制。计算的能量谱表明，该反应遵循粉笔-Harrod机制。速率确定步骤是PD-AU簇中的液压液，而PD-AU（111）合金表面中的Si-C还原消除。 PD位点作为在实验中观察到的吸附部位和反应性中心。周边钯金桥和Au位点也与此有关的键活化并接受底物或中间体的反应，这是在钯金合金催化剂特性和均相催化剂不可用期间。氢化硅烷化反应在没有过多的能量屏障和PD-Au合金催化剂中的中间体过稳定的中间体进行。由于高能量屏障（Au）或过稳定的中间体（Pd），单金属Au和Pd催化剂不是优选的。 PD原子位点及其周围PD-Au桥或Au位点的相关性的本图像对于开发相关催化反应的合金催化剂将是有用的。

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