AbstractWe show that countercations exert a remarkable influence on the ability of anionic cobaltate salts to catalyze challenging alkene hydrogenations. An evaluation of the catalytic properties of [Cat][Co(η4‐cod)2] (Cat=K (1), Na (2), Li (3), (Depnacnac)Mg (4), and N(nBu)4 (5); cod=1,5‐cyclooctadiene, Depnacnac=2,6‐Et2C6H3NC(CH3)}2CH)]) demonstrated that the lithium salt 3 and magnesium salt 4 drastically outperform the other catalysts. Complex 4 was the most active catalyst, which readily promotes the hydrogenation of highly congested alkenes under mild conditions. A plausible catalytic mechanism is proposed based on density functional theory (DFT) investigations. Furthermore, combined molecular dynamics (MD) simulation and DFT studies were used to examine the turnover‐limiting migratory insertion step. The results of these studies suggest an active co‐catalytic role of the counterion in the hydrogenation reaction through the coordination to cobalt hydride intermediates.
摘要 我们的研究表明,反阳离子对阴离子钴盐催化具有挑战性的烯氢化反应的能力有显著影响。对[Cat][Co(η4-cod)2](Cat=K (1)、Na (2)、Li (3)、(Depnacnac)Mg (4)和 N(nBu)4 (5);cod=1,5-环辛二烯,Depnacnac=2,6-Et2C6H3NC(CH3)}2CH)]的催化特性进行的评估表明,锂盐 3 和镁盐 4 的性能大大优于其他催化剂。络合物 4 是最活跃的催化剂,在温和的条件下很容易促进高稠度烯烃的氢化。基于密度泛函理论(DFT)研究,提出了一种合理的催化机理。此外,还采用分子动力学(MD)模拟和 DFT 研究相结合的方法对限制周转的迁移插入步骤进行了研究。这些研究结果表明,反离子通过与氢化钴中间体配位,在氢化反应中发挥了积极的协同催化作用。