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Predicting Hydride Donor Strength via Quantum Chemical Calculations of Hydride Transfer Activation Free Energy
The Journal of Physical Chemistry B ( IF 3.3 ) Pub Date : 2018-01-05 00:00:00 , DOI: 10.1021/acs.jpcb.7b12093
Abdulaziz Alherz 1 , Chern-Hooi Lim 1, 2 , James T. Hynes 2, 3 , Charles B. Musgrave 1, 2, 4
Affiliation  

We propose a method to approximate the kinetic properties of hydride donor species by relating the nucleophilicity (N) of a hydride to the activation free energy ΔG of its corresponding hydride transfer reaction. N is a kinetic parameter related to the hydride transfer rate constant that quantifies a nucleophilic hydridic species’ tendency to donate. Our method estimates N using quantum chemical calculations to compute ΔG for hydride transfers from hydride donors to CO2 in solution. A linear correlation for each class of hydrides is then established between experimentally determined N values and the computationally predicted ΔG; this relationship can then be used to predict nucleophilicity for different hydride donors within each class. This approach is employed to determine N for four different classes of hydride donors: two organic (carbon-based and benzimidazole-based) and two inorganic (boron and silicon) hydride classes. We argue that silicon and boron hydrides are driven by the formation of the more stable Si–O or B–O bond. In contrast, the carbon-based hydrides considered herein are driven by the stability acquired upon rearomatization, a feature making these species of particular interest, because they both exhibit catalytic behavior and can be recycled.

中文翻译:

通过氢化物转移活化自由能的量子化学计算预测氢化物给体强度

我们提出了一个方法,通过亲核性(涉及近似氢化物供体物种的动力学性质Ñ氢化物)到自由活化能Δ ģ其相应的氢化物转移反应。N是与氢化物转移速率常数相关的动力学参数,可量化亲核氢化物的捐赠趋势。我们的方法估计Ñ使用量子化学计算来计算Δ ģ用于从氢化物供体到CO氢化物传输2在溶液中。然后在实验确定的N之间建立每种氢化物的线性相关性值和计算预测Δ ģ ; 然后可以使用这种关系来预测每个类别中不同氢化物供体的亲核性。该方法用于确定四种不同类型的氢化物供体的N:两种有机(碳基和苯并咪唑基)和两种无机(硼和硅)氢化物。我们认为硅和硼氢化物是由更稳定的Si–O或B–O键的形成驱动的。相比之下,本文考虑的碳基氢化物是由重新麦芽化时获得的稳定性驱动的,这是使这些物质特别受关注的特征,因为它们都具有催化性能并且可以循环使用。
更新日期:2018-01-05
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