Reactivity of borylenes toward ethyne, ethene, and methane.
Reactivity of borylenes toward ethyne, ethene, and methane.
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DOI：
10.1021/ja306346h
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发表时间：
2012-10
影响因子：
15
通讯作者：
M. Krasowska;H. Bettinger
中科院分区：
文献类型：
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作者：
M. Krasowska;H. Bettinger
采用混合密度泛函（B3 LYP）和二阶Møller-Plesset微扰理论，结合6-311+G** 和cc-pVTZ基组，研究了各种取代的亚硼基BR（其中R = H、F、Cl、Br、CH（3）、Ph、NH（2）、NHMe和NMe（2））在最低单重态和三重态电子态的电子和几何结构。通过结合CC-pVTZ基组的MP2方法以及结合aug-cc-pVTZ基组的耦合簇[CCSD（T）]计算，研究了单重态硼烯对典型饱和和不饱和烃的反应性。以乙炔和乙烯为模型化合物，研究硼烯与不饱和CC键加成反应的热力学和机理。并研究了硼烯在甲烷C-H键上的插入反应。亚硼基与多个C-C键的加成反应是强放热反应。在BH分子的情况下，反应进行无障碍，是最放热的。对于环硼烯插入甲烷的反应，可以确定两种方法。再次，计算了BH插入的最小反应能垒和最高反应能，而BF分子获得了最高反应能垒和最小放热。前线分子轨道能量，势垒高度，反应能量和过渡态几何形状的基础上BH是最亲电的硼，其次是BPh，而aminoborylenes和BF是最亲核的研究衍生物。因此，BH的反应具有最小的势垒（如果有的话）和最大的反应能量，而BF的反应具有最高的势垒和最小的反应能量。
The electronic and geometric structure of various substituted borylenes BR (where R = H, F, Cl, Br, CH(3), Ph, NH(2), NHMe, and NMe(2)) in their lowest singlet and triplet electronic states was investigated by computational means using hybrid density functional (B3LYP) and second-order Møller-Plesset perturbation theories combined with 6-311+G** and cc-pVTZ basis sets. The reactivity of singlet borylenes towards prototypical saturated and unsaturated hydrocarbons was examined by the MP2 method in conjugation with the cc-pVTZ basis set and also by coupled cluster [CCSD(T)] computations in combination with the aug-cc-pVTZ basis set. To study the energetics and the mechanism of the addition reaction of borylenes to unsaturated CC bonds, ethyne and ethene are chosen as model compounds. The insertion reaction of borylene into a C-H bond of methane was also investigated. The addition reactions of borylenes to multiple C-C bonds are strongly exothermic. In case of the BH molecule the reactions proceed without barrier and are the most exothermic. For the insertion reaction of borylenes into methane, two approaches could be identified. Again, the smallest reaction barriers and highest reaction energies were computed for the BH insertion, while the highest barriers and the smallest exothermicities were obtained for the BF molecule. On the basis of frontier molecular orbital energies, barrier heights, reaction energies, and transition state geometries BH is the most electrophilic borylene, followed by BPh, while aminoborylenes and BF are the most nucleophilic ones among the investigated derivatives. Accordingly, reactions of BH have the smallest barriers (if there is one at all) and the largest reaction energies, while the reactions of BF have the highest barriers and the smallest reaction energies.