The effect of substitution on the potential energy surfaces of RB≡PR (R = H, F, OH, SiH₃, and CH₃) is studied using density functional theories (M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, and B3LYP/LANL2DZ+dp). There is significant theoretical evidence that RB≡PR compounds with smaller substituents are fleeting intermediates, so they would be difficult to be detected experimentally. These theoretical studies using the M06-2X/Def2-TZVP method demonstrate that only the triply bonded R′B≡PR′ molecules bearing sterically bulky groups (R′ = Tbt (=C₆H₂-2,4,6-{CH(SiMe₃)₂}₃), SiMe(SitBu₃)₂, Ar* (=C₆H₃-2,6-(C₆H₂-2,4,6-i-Pr₃)₂), and SiiPrDis₂) are significantly stabilized and can be isolated experimentally. Using the simple valence-electron bonding model and some sophisticated theories, the bonding character of R′B≡PR′ should be viewed as R′BI PR′. The present theoretical observations indicate that both the electronic and the steric effect of bulkier substituent ligands play a key role in making triply bonded R′B≡PR′ species synthetically accessible and isolable in a stable form.

中文翻译：

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三键结合的硼≡磷分子：这可能吗？

取代RB≡PR（R = H，F，OH，SiH基的势能表面上的效果₃，和CH ₃），使用密度泛函理论（M06-2X / DEF2-TZVP，B3PW91 / DEF2-TZVP研究，和B3LYP / LANL2DZ + dp）。有重要的理论证据表明，具有较小取代基的RB≡PR化合物是短暂的中间体，因此很难通过实验检测到。这些使用M06-2X / Def2-TZVP方法进行的理论研究表明，只有三重键合的R'B bondedPR'分子带有空间庞大的基团（R'= Tbt（= C ₆ H ₂ -2,4,6- {CH （SiMe ₃）₂ } ₃），SiMe（Si t Bu ₃）₂中，Ar *（= C ₆ H ^ ₃ -2,6-（C ₆ H ^ ₂ -2,4,6-我-Pr ₃）₂），和Si我PrDis ₂）被显著稳定，可以通过实验来分离。使用简单的价电子键合模型和一些复杂的理论，R'B≡PR'的键合特性应视为R'BI PR'。目前的理论观察表明，更大的取代基配体的电子和空间效应在使三键结合的R'B≡PR'物种可合成且可稳定分离方面起着关键作用。