Yan Bingfei, Li Wenzuo, Xiao Cuiping, Li Qingzhong, Cheng Jianbo
The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai, 264005, People's Republic of China.
J Mol Model. 2015 Apr;21(4):76. doi: 10.1007/s00894-015-2640-2. Epub 2015 Mar 10.
The unique substitution reactions of the three-membered-ring silylenoid H2SiLiF with GeH3X (X = F, Cl, Br) were investigated using ab initio and density functional theory calculations. All stationary points on the potential energy surfaces were optimized at the B3LYP/6-311 + G (d, p) level of theory and the QCISD method was then used to calculate the single-point energies. Theoretical calculations predicted that the substitution reactions of H2SiLiF with GeH3X proceed via two reaction paths (I and II), while forming the same product H2FSi-GeH3. In either pathway, there is one precursor complex (Q), one transition state (TS), and one intermediate (IM) connecting the reactants and products. The substitution reaction barriers of H2SiLiF with GeH3X for path I (48.49, 42.71, and 38.71 kJ mol(-1)) decreased with the increase for the same-family element X from up to down in the periodic table, whereas the substitution barriers for path II (6.51, 22.04, and 23.62 kJ mol(-1)) increased with the increase in atomic number of X (X = F, Cl, Br). Path II was more favorable than path I. All the substitution reactions of H2SiLiF with GeH3X were exothermic. The elucidation of the unique mechanism of these substitution reactions suggests a new reaction mode of silicon-germanium bond formation.
采用从头算和密度泛函理论计算方法，研究了三元环硅烯醇盐H2SiLiF与GeH3X（X = F、Cl、Br）的独特取代反应。在B3LYP/6-311+G(d, p)理论水平上对势能面上的所有驻点进行了优化，然后用QCISD方法计算单点能量。理论计算预测，H2SiLiF与GeH3X的取代反应通过两条反应路径（I和II）进行，同时形成相同的产物H2FSi-GeH3。在任一反应路径中，都有一个前体配合物（Q）、一个过渡态（TS）和一个连接反应物与产物的中间体（IM）。H2SiLiF与GeH3X在路径I上的取代反应势垒（48.49、42.71和38.71 kJ mol(-1)）随着同族元素X在周期表中从上到下的增加而降低，而路径II的取代势垒（6.51、22.04和23.62 kJ mol(-1)）随着X原子序数的增加而增加（X = F、Cl、Br）。路径II比路径I更有利。H2SiLiF与GeH3X的所有取代反应都是放热的。对这些取代反应独特机理的阐释揭示了一种新的硅锗键形成反应模式。
