Lu Jia-Syun, Yang Ming-Chung, Su Ming-Der
Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan.
Dalton Trans. 2017 Feb 14;46(6):1848-1856. doi: 10.1039/c6dt04522g.
The effect of substitution on the potential energy surfaces of RGa[triple bond, length as m-dash]SbR (R = F, OH, H, CH, SiH, SiMe(SitBu), SiiPrDis and NHC) is studied using density functional theory (M06-2X/Def2-TZVP, B3PW91/Def2-TZVP and B3LYP/LANL2DZ + dp). The computational results show that all of the triply bonded RGa[triple bond, length as m-dash]SbR molecules have a preference for a bent geometry (i.e., ∠RGaSb ≈ 180° and ∠GaSbR ≈ 90°), which can be described using a valence bond model. The theoretical results show that because RGa[triple bond, length as m-dash]SbR has smaller electropositive groups, it could be both kinetically and thermodynamically stable and may be experimentally detectable. However, these theoretical results predict that the triply bonded R'Ga[triple bond, length as m-dash]SbR' molecules that have bulkier groups (R' = SiMe(SitBu), SiiPrDis, and NHC) are kinetically stable. In other words, both the electronic and the steric effects of bulkier substituent groups mean that it should be possible to experimentally isolate triply bonded RGa[triple bond, length as m-dash]SbR molecules in a stable form.
采用密度泛函理论（M06 - 2X/Def2 - TZVP、B3PW91/Def2 - TZVP和B3LYP/LANL2DZ + dp）研究了取代基对RGa≡SbR（R = F、OH、H、CH、SiH、SiMe(SitBu)、SiiPrDis和NHC）势能面的影响。计算结果表明，所有三键连接的RGa≡SbR分子都倾向于弯曲几何结构（即∠RGaSb≈180°且∠GaSbR≈90°），这可以用价键模型来描述。理论结果表明，由于RGa≡SbR具有较小的正电基团，它在动力学和热力学上都可能是稳定的，并且可能在实验中被检测到。然而，这些理论结果预测，具有较大基团（R' = SiMe(SitBu)、SiiPrDis和NHC）的三键连接的R'Ga≡SbR'分子在动力学上是稳定的。换句话说，较大取代基基团的电子效应和空间效应都意味着应该有可能以稳定的形式通过实验分离出三键连接的RGa≡SbR分子。
