Elementary reaction mechanisms constitute a fundamental infrastructure for chemical processes as a whole. However, while these mechanisms are well understood for second-period elements, involving those of the third period and beyond can introduce unorthodox reactivity. Combining crossed molecular beam experiments with electronic structure calculations and molecular dynamics simulations, we provide compelling evidence on an exotic insertion of an unsaturated sigma doublet radical into a silicon-hydrogen bond as observed in the barrierless gas-phase reaction of the D1-ethynyl radical (C 2 D) with silane (SiH 4 ). This pathway, which leads to the D1-silylacetylene (SiH 3 CCD) product via atomic hydrogen loss, challenges the prerequisite and fundamental concept that two reactive electrons and an empty orbital are required for the open shell, unsaturated radical reactant to insert into a single bond.

中文翻译：

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通过违反直觉的乙炔自由基 （C 2 H） 插入物制备硅基乙炔 （SiH 3 CCH） 的气相制备


基本反应机理构成了整个化学过程的基本基础设施。然而，虽然这些机制对于第二周期元素来说已经很好理解，但涉及第三周期及以后的元素可能会引入非正统的反应性。将交叉分子束实验与电子结构计算和分子动力学模拟相结合，我们提供了令人信服的证据，证明不饱和 σ 双峰自由基奇异地插入硅氢键中，如 D1-乙炔自由基 （C 2 D） 与硅烷 （SiH 4） 的无屏障气相反应中观察到的那样。该途径通过原子氢损失产生 D1-硅基乙炔 （SiH 3 CCD） 产物，挑战了开壳不饱和自由基反应物插入单个键需要两个反应电子和一个空轨道的先决条件和基本概念。