Palladium on Polydopamine: Its True Potential in Catalytic Transfer Hydrogenations and Heck Coupling Reactions
Palladium on Polydopamine: Its True Potential in Catalytic Transfer Hydrogenations and Heck Coupling Reactions
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DOI：
10.1002/cctc.201700609
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发表时间：
2017-08
期刊：
影响因子：
4.5
通讯作者：
Attila Kunfi;V. Szabó;Á. Mastalir;I. Bucsi;M. Mohai;P. Németh;I. Bertóti;G. London
中科院分区：
文献类型：
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作者：
Attila Kunfi;V. Szabó;Á. Mastalir;I. Bucsi;M. Mohai;P. Németh;I. Bertóti;G. London
报道了 Pd-聚多巴胺和磁性 Fe3O4@Pd-聚多巴胺催化剂在催化转移氢化反应和 Heck 芳基化反应中的应用。尽管发现羰基化合物的还原不太普遍，但可以有效地将多种带有给电子和吸电子取代基的芳香硝基化合物还原为相应的苯胺。在后一种情况下，只有芳香酮可以被还原为相应的醇，而醛底物不受影响，这可能是由于它们与催化剂载体发生反应导致催化剂失活。通过使用磁性 Fe3O4@Pd-聚多巴胺系统，促进了催化剂的回收和连续五个循环的再利用，而硝基还原活性没有明显损失。 Heck 反应中催化剂的效率与转移氢化中的催化剂效率相当，然而，在这种情况下，在重复使用时没有观察到催化活性，这可能是金属浸出的结果。我们还探索了串联赫克反应/催化转移氢化序列，然而，这两种反应在应用条件下表现出有限的兼容性。
The application of Pd–polydopamine and magnetic Fe3O4@Pd–polydopamine catalysts in catalytic transfer hydrogenation reactions and the Heck arylation is reported. The reduction of a wide range of aromatic nitro‐compounds bearing both electron‐donating and ‐withdrawing substituents to the corresponding anilines could be efficiently performed, although the reduction of carbonyl compounds was found to be less general. In the latter case, only aromatic ketones could be reduced to the corresponding alcohols, whereas aldehyde substrates were unaffected, which may be owing to their reaction with the catalyst support leading to catalyst deactivation. By using magnetic Fe3O4@Pd–polydopamine system, facilitated catalyst recovery and reuse for five consecutive cycles without considerable loss of activity in nitro‐group reduction. The efficiency of the catalyst in Heck reactions was comparable to that in transfer hydrogenation, however, no catalytic activity was observed upon reuse in this case, likely as a result of metal leaching. We also explored tandem Heck reaction/catalytic transfer hydrogenation sequences, however, the two reactions showed limited compatibility under the applied conditions.