Theoretical studies of the [2 + 4] Diels-Alder cycloaddition reactions of alkene analogues of the group 13 elements with toluene.
Theoretical studies of the [2 + 4] Diels-Alder cycloaddition reactions of alkene analogues of the group 13 elements with toluene.
复制标题
第 13 族元素的烯烃类似物与甲苯的 [2 4] Diels-Alder 环加成反应的理论研究。
DOI：
10.1021/ic061100u
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发表时间：
2007
影响因子：
4.6
通讯作者：
M. Su
中科院分区：
文献类型：
--
作者：
Sing;Jeng;M. Su
用密度泛函理论（B3 LYP/LANL 2DZ）研究了含13族元素的形式双键分子环加成反应的势能面.选择了五种13族烯烃类似物ArX=XAr（其中X = B）、Al、Ga、In和Tl作为模型反应物。我们目前的理论工作预测，ArX=XAr中的单重态-三重态分裂越小，活化能垒越低，反过来，其[4 + 2]环加成反应越快。此外，理论研究表明，相对二聚反应活性按B > Al > Ga > In > Tl的顺序降低。也就是说，第13族原子（X）越重，其二金属烯对化学反应越稳定。因此，我们的研究结果预测，含有较重的第13族元素（特别是，X = Ga，In和Tl）的双金属烯应该是稳定的，应该很容易在室温下合成和分离。这与现有的实验观察结果吻合得很好。除此之外，Pross和Shaik的构型混合模型中描述的二金属烯的单重态-三重态能量分裂可以用作预测其反应性的诊断工具。所获得的结果允许作出一些预测。
The potential energy surfaces for the cycloaddition reactions of formally double-bonded molecules containing group 13 elements have been studied using density functional theory (B3LYP/LANL2DZ). Five group 13 alkene analogues, ArX=XAr, where X = B, Al, Ga, In, and Tl, have been chosen as model reactants in this work. Our present theoretical work predicts that the smaller the singlet-triplet splitting in ArX=XAr, the lower the activation barrier and, in turn, the more rapid are its [4 + 2] cycloaddition reactions. Moreover, the theoretical investigations suggest that the relative dimeric reactivity decreases in the order B > Al > Ga > In > Tl. That is, the heavier the group 13 atom (X), the more stable is its dimetallene toward chemical reactions. In consequence, our results predict that the dimetallenes containing heavier group 13 elements (in particular, X = Ga, In, and Tl) should be stable and should be readily synthesized and isolated at room temperature. This is in good agreement with available experimental observations. Besides this, the singlet-triplet energy splitting of a dimetallene, as described in the configuration mixing model attributed to the work of Pross and Shaik, can be used as a diagnostic tool to predict its reactivity. The results obtained allow a number of predictions to be made.