Substituent Effects on Boron–Bismuth Triple Bond: A New Target for Synthesis

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• 作者：Jia-Syun Lu ; Shih-Hao Su ; Ming-Chung Yang ; Xiang-Ting Wen ; Jia-Zhen Xie ; Ming-Der Su
• 刊名：Organometallics
• 出版年：2016
• 出版时间：December 12, 2016
• 年：2016
• 卷：35
• 期：23
• 页码：3924-3931
• 全文大小：532K
• ISSN：1520-6041

文摘

The substituent effects on the potential energy surfaces of RB≡BiR (R = F, OH, H, CH₃, SiH₃, Tbt, Ar*, SiMe(SitBu₃)₂, and SiiPrDis₂) are determined using density functional theories (M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, and B3LYP/LANL2DZ+dp). The theoretical results show that all of the triply bonded RB≡BiR molecules prefer to adopt a bent geometry (i.e., ∠RBBi ≈ 180° and ∠BBiR ≈ 90°), which agrees well with the valence-electron bonding model. It is also demonstrated that the smaller groups, such as R = H, F, OH, CH₃, and SiH₃, neither kinetically nor thermodynamically stabilize the triply bonded RB≡BiR compounds, except for H₃SiB≡BiSiH₃. However, triply bonded R′B≡BiR′ molecules that feature bulkier substituents (R′ = SiiPrDis₂, SiMe(SitBu₃)₂, Tbt, and Ar*) are predicted to have a thermodynamic and kinetic global minimum. This theoretical study finds that both the steric and the electronic effects of bulkier substituent groups play a significant role in forming triply bonded RB≡BiR species that are experimentally obtainable and isolable in a stable form.