Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
Heidelberg Institute for Theoretical Studies (HITS gGmbH), Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany and Interdisciplinary Center for Scientific Computing (IWR), Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 205, 69120 Heidelberg, Germany.
J Chem Phys. 2022 May 21;156(19):194113. doi: 10.1063/5.0090267.
The potential energy surfaces of 15 tetrahedral p-block element hydrides were screened on the multireference level. It was addressed whether stereoinversion competes against other reactions, such as reductive H-elimination or hydride loss, and if so, along which pathway the stereomutation occurs. Importantly, stereoinversion transition structures for the ammonium cation (C) and the tetrahydridoborate anion (C) were identified for the first time. Revisiting methane's C symmetric inversion transition structure with the mHEAT+ protocol revealed an activation enthalpy for stereoinversion, in contrast to all earlier studies, which is 5 kJ mol below the C-H bond dissociation enthalpy. Square planar structures were identified lowest in energy only for the inversion of AlH , but a novel stepwise C-inversion was discovered for SiH or PH . Overall, the present contribution delineates essentials of the potential energy surfaces of p-block element hydrides, while structure-energy relations offer design principles for the synthetically emerging field of structurally constrained compounds.
15 种四面体型 p 区元素氢化物的势能面在多参考水平上进行了筛选。研究了旋光反转是否与其他反应（如还原 H 消除或氢化物损失）竞争，如果是，旋光转变沿着哪个途径发生。重要的是，首次为铵阳离子（C）和四氢硼酸根阴离子（C）确定了旋光反转过渡态结构。使用 mHEAT+ 协议重新研究甲烷的 C 对称反转过渡结构表明，旋光反转的活化焓与所有早期研究相反，比 C-H 键离解焓低 5 kJ mol。仅在 AlH 的反转中，平面正方形结构被确定为能量最低，但对于 SiH 或 PH ，发现了一种新的逐步 C 反转。总的来说，本研究阐明了 p 区元素氢化物势能面的要点，而结构-能量关系为结构约束化合物这一新兴合成领域提供了设计原则。
