In Situ Generation of Catalytically Relevant Nanoparticles from a Molecular Pincer Iridium Precatalyst during Polyol Deoxygenation
In Situ Generation of Catalytically Relevant Nanoparticles from a Molecular Pincer Iridium Precatalyst during Polyol Deoxygenation
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DOI：
10.1021/acscatal.0c03180
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发表时间：
2021-01-15
期刊：
影响因子：
12.9
通讯作者：
Scheuermann, Margaret L.
中科院分区：
文献类型：
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作者：
Gitnes, Rachael M.;Wang, Maggie;Scheuermann, Margaret L.
钳形配合物如（（POCOP）-P-R）Ir基物种（（POCOP）-P-R = kappa（3）-C6 H3 - 1，3-[P（R）（2）]（2））被广泛用作有机转化的预催化剂，这些转化的许多机理研究基于预催化剂在催化条件下保持其分子性质的假设。我们证明，即使是（（POCOP）-P-tBu）IrCO（（POCOP）-P-tBu = kappa（3）-C6 H3 - 1，3-[P（R）（2）]（2）），一种因其稳定性而被重视的预催化剂，也可以在升高的温度下在多元醇脱氧所需的酸性还原条件下容易形成纳米颗粒，并且原位形成的纳米颗粒可以有助于观察到的氢化活性。铱纳米粒子从反应混合物中分离，通过离心和检测玻璃和聚四氟乙烯（PTFE）反应器内衬表现出高度的聚集和抵抗常见的清洁协议。
Pincer complexes such as ((POCOP)-P-R)Ir-based species ((POCOP)-P-R = kappa(3)-C6H3-1,3-[P(R)(2)](2)) are widely used as precatalysts for organic transformations with many mechanistic studies of these transformations based on the assumption that the precatalysts retain their molecular nature under catalytic conditions. We demonstrate that even ((POCOP)-P-tBu)IrCO ((POCOP)-P-tBu = kappa(3)-C6H3-1,3-[P(R)(2)](2)), a precatalyst valued for its stability, can be susceptible to the formation of nanoparticles at elevated temperatures under the acidic reducing conditions required for polyol deoxygenation and that the nanoparticles formed in situ can HO, contribute to the observed hydrogenation activity. The iridium nanoparticles isolated from reaction mixtures by centrifugation and detected on glass and polytetrafluoroethylene (PTFE) reactor liners exhibit a high degree of aggregation and resist common cleaning protocols.