Grignard reactions are of importance in organic chemistry for the synthesis β‐keto esters and diethyl malonate, alcohols, aldehydes or ketones, monocarboxylic acids, and other organometallic compounds. Generally, the heterolytic dissociation of C─Mg bond in Grignard reagent is the key step in these reactions. Recently, homolytic cleavage of the C─Mg bond in Grignard reagents has been reported in the preparation of stable radicals. These reactive species react with other compounds, which result in the formation of hydrocarbons and their derivatives. Therefore, the study of homolytic cleavage of C─Mg bonds is quite vital to better understand the kinetics and thermodynamics of these reactions. In the current study, a benchmark approach is adopted to find a cost‐effective and accurate density functional (DF) for bond dissociation energies measurement of the C─Mg bond of Grignard reagents. Twenty‐nine DFs from 13 density functional theory (DFT) classes with three types of basis sets (Pople' 6‐31G(d) and 6‐311G(d), Dunning's aug‐cc‐pVDZ, and Karlsruhe' def2‐SVP basis sets) are implemented for the measurement of dissociation energies of the C─Mg bond. Theoretical dissociation energy values are compared with experimental reported values of the C─Mg bond of selected Grignard reagents. TPSSTPSS of the meta‐GGA class with 6‐31G (d) basis set gave accurate results, and its Pearson's correlation is 0.95. SD, root mean square deviation, and mean unsigned error of this method are 2.36 kcal mol⁻¹, 2.33 kcal mol⁻¹, and −0.46 kcal mol⁻¹, respectively. TPSSTPSS of the meta‐GGA class is a one‐electron, self‐interaction, error‐free Tao‐Perdew‐Staroverov‐Scuseria functional that performed better with the 6‐31G(d) basis set.

中文翻译：

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基准方法寻找格利雅试剂C-Mg键的均质裂解的经济有效且精确的密度泛函

格氏反应在有机化学中对于合成β至关重要酮酸酯和丙二酸二乙酯，醇，醛或酮，一元羧酸和其他有机金属化合物。通常，格氏试剂中C-Mg键的杂化解离是这些反应的关键步骤。最近，有报道称在制备稳定的自由基时，格氏试剂中的C-Mg键均被裂解。这些反应性物质与其他化合物反应，导致形成烃及其衍生物。因此，对C-Mg键的均质裂解的研究对于更好地理解这些反应的动力学和热力学至关重要。在当前的研究中，采用基准方法来找到一种经济高效且准确的密度泛函（DF），用于格氏试剂C-Mg键的键解离能测量。来自13种密度泛函理论（DFT）类的29个DF，具有三种类型的基础集（Pople的6-31G（d）和6-311G（d），Dunning的aug-cc-pVDZ和Karlsruhe的def2-SVP基础）集合）用于测量C-Mg键的解离能。将理论解离能值与所选格氏试剂的C-Mg键的实验报告值进行比较。具有6-31G（d）基集的meta-GGA类的TPSSTPSS提供了准确的结果，其Pearson相关系数为0.95。该方法的SD，均方根偏差和平均无符号误差为2.36 kcal mol 将理论解离能值与所选格氏试剂的C-Mg键的实验报告值进行比较。具有6-31G（d）基集的meta-GGA类的TPSSTPSS提供了准确的结果，其Pearson相关系数为0.95。该方法的SD，均方根偏差和平均无符号误差为2.36 kcal mol 将理论解离能值与所选格氏试剂的C-Mg键的实验报告值进行比较。具有6-31G（d）基集的meta-GGA类的TPSSTPSS提供了准确的结果，其Pearson相关系数为0.95。该方法的SD，均方根偏差和平均无符号误差为2.36 kcal mol^-1，2.33千卡摩尔^-1，和-0.46千卡摩尔^-1，分别。TPSSTPSS是meta-GGA类的，是一种单电子，自交互，无错误的Tao-Perdew-Staroverov-Scuseria功能，在6-31G（d）基组下表现更好。