A heterogeneous single-atom palladium catalyst surpassing homogeneous systems for Suzuki coupling
A heterogeneous single-atom palladium catalyst surpassing homogeneous systems for Suzuki coupling
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DOI：
10.1038/s41565-018-0167-2
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发表时间：
2018-08-01
影响因子：
38.3
通讯作者：
Perez-Ramirez, Javier
中科院分区：
文献类型：
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作者：
Chen, Zupeng;Vorobyeva, Evgeniya;Perez-Ramirez, Javier
钯催化的交叉偶联反应是精细化学合成的核心工具，尽管在产品纯化和催化剂重复使用方面存在公认的挑战，但主要使用可溶的金属络合物(1-3)。将这些均相催化剂固定在不溶性载体上的尝试因稳定性不佳而受阻，这导致由于金属浸出或聚集而导致性能逐渐恶化(4)。负载型钯纳米颗粒的替代应用面临限制，因为在避免底物或产品热降解所需的温和条件下活性不足。单原子多相催化剂位于前线(5-)(18)。在这里，我们展示了锚定在剥离的石墨化碳氮化物(Pd-ECN)上的Pd原子兼具两者的优势，因为它们包含一种固体催化剂，与铃木偶联用最先进的均相催化剂的高化学选择性和广泛的官能团耐受性相匹配，并且还表现出强大的流动稳定性。ECN大杂环内的自适应配位环境促进了每个催化步骤。这些发现说明了固体主体中的单原子纳米结构为催化过程带来的令人兴奋的机会，这些过程仍然很难实现多相化。
Palladium-catalysed cross-coupling reactions, central tools in fine-chemical synthesis, predominantly employ soluble metal complexes despite recognized challenges with product purification and catalyst reusability(1-3). Attempts to tether these homogeneous catalysts on insoluble carriers have been thwarted by suboptimal stability, which leads to a progressively worsening performance due to metal leaching or clustering(4). The alternative application of supported Pd nanoparticles has faced limitations because of insufficient activity under the mild conditions required to avoid thermal degradation of the substrates or products. Single-atom heterogeneous catalysts lie at the frontiers(5-)(18). Here, we show that the Pd atoms anchored on exfoliated graphitic carbon nitride (Pd-ECN) capture the advantages of both worlds, as they comprise a solid catalyst that matches the high chemoselectivity and broad functional group tolerance of stateof-the-art homogeneous catalysts for Suzuki couplings, and also demonstrate a robust stability in flow. The adaptive coordination environment within the macroheterocycles of ECN facilitates each catalytic step. The findings illustrate the exciting opportunities presented by nanostructuring single atoms in solid hosts for catalytic processes that remain difficult to heterogenize.