Formation of Formic Acid Derivatives through Activation and Hydroboration of CO 2 by Low-Valent Group 14 (Si, Ge, Sn, Pb) Catalysts
Formation of Formic Acid Derivatives through Activation and Hydroboration of CO 2 by Low-Valent Group 14 (Si, Ge, Sn, Pb) Catalysts
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低价14族（Si、Ge、Sn、Pb）催化剂活化和硼氢化CO 2 形成甲酸衍生物
DOI：
10.1021/acs.jpca.9b11648
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Toro-Labbé, Alejandro
中科院分区：
文献类型：
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作者：
Villegas-Escobar, Nery;Schaefer, Henry F.;Toro-Labbé, Alejandro
低价主族元素的化学在过去的十年里引起了人们的广泛关注。这些物种是相关的，因为它们能够在催化应用中模拟过渡金属的行为，降低材料成本和毒性。在这篇文章中，我们研究了L1 EH催化剂（E = Si（II），Ge（II），Sn（II）和Pb（II）; L1= [ArNC（Me）CHC（Me）NAr]，Ar = 2，6-iPr 2C 6 H3）通过硼氢化CO2形成甲酸衍生物。势能面上相关结构的详细表征使我们能够合理化CO2硼氢化反应的不同路径。有趣的是，据发现，根据整个催化循环的活化能，CO2的转化过程变得更有利于向下组14。然而，一个有效的能量减少的过程（作为参考的CO2和HBpin之间的非催化反应）证明只是从锗类似物。在本研究中发现的反应性的趋势是在中心主族元素的变化的直接后果，使增强的极性特征的E-H（L1 EH在CO2活化步骤）和E-O（金属甲酸盐在硼氢化步骤）键作为原子半径的增加。通过非共价相互作用指数（NCI）和微扰理论（SAPT）合理化的硼氢化反应步骤中发现的反应中间体的瞬态稳定。这项计算研究突出了在第14族为基础的氢化物催化剂的反应趋势，在氢化金属化和后硼氢化形成甲酸中间体。我们希望这项研究将激发进一步的实验工作，在低价铅化学。
The chemistry of low-valent main group elements has attracted much attention in the past decade. These species are relevant because they have been able to mimic transition metal behavior in catalytic applications, with decreased material costs and diminished toxicity. In this contribution, we study the L1EH catalysts (E = Si(II), Ge(II), Sn(II), and Pb(II); L1= [ArNC(Me)CHC(Me)NAr] with Ar = 2,6-iPr2C6H3) for the formation of formic acid derivatives through hydroboration of CO2. Detailed characterization of relevant structures on the potential energy surface enabled us to rationalize different paths for the hydroboration of CO2. Interestingly, it was found that according to the activation energies for the whole catalytic cycle, the process of transformation of CO2becomes more favored going down group 14. However, an effective energetic decrease for the process (taking as the reference the uncatalyzed reaction between CO2and HBpin) is evidenced just from the germanium analogue. The trend in reactivity found in the present study is a direct consequence of the change in the central main group element, enabling enhanced polar character of the E–H (L1EH in the CO2activation step) and E–O (metal formates in the hydroboration step) bonds as the atomic radius increases. The transient stabilization of reaction intermediates found in the hydroboration step was rationalized through the non-covalent interaction index (NCI) and symmetry-adapted perturbation theory (SAPT). This computational study highlights the reactivity trends in group-14-based hydride catalysts in hydrometalation and posterior hydroboration to form formic acid intermediates. We hope that this study will motivate further experimental work in low-valent lead chemistry.