Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI, 96822, USA.
Department of Chemistry, Florida A&M University, Tallahassee, FL, 32307, USA.
Angew Chem Int Ed Engl. 2017 Jan 24;56(5):1264-1268. doi: 10.1002/anie.201611107. Epub 2017 Jan 2.
The hitherto elusive disilavinylidene (H SiSi) molecule, which is in equilibrium with the mono-bridged (Si(H)SiH) and di-bridged (Si(H )Si) isomers, was initially formed in the gas-phase reaction of ground-state atomic silicon (Si) with silane (SiH ) under single-collision conditions in crossed molecular beam experiments. Combined with state-of-the-art electronic structure and statistical calculations, the reaction was found to involve an initial formation of a van der Waals complex in the entrance channel, a submerged barrier to insertion, intersystem crossing (ISC) from the triplet to the singlet manifold, and hydrogen migrations. These studies provide a rare glimpse of silicon chemistry on the molecular level and shed light on the remarkable non-adiabatic reaction dynamics of silicon, which are quite distinct from those of isovalent carbon systems, providing important insight that reveals an exotic silicon chemistry to form disilavinylidene.
迄今难以捉摸的二硅烯基（H SiSi）分子，与单桥联（Si（H）SiH）和双桥联（Si（H ）Si）异构体处于平衡状态，最初是在气相条件下形成的，在交叉分子束实验中，基态原子硅（Si）与硅烷（SiH ）在单次碰撞条件下反应。结合最先进的电子结构和统计计算，发现该反应涉及入口通道中范德华复合物的初始形成、插入的淹没势垒、三重态到单重态的系间窜越（ISC）以及氢迁移。这些研究提供了硅化学在分子水平上的罕见一瞥，并阐明了硅的显著非绝热反应动力学，这与等电子碳系统有很大的不同，为形成二硅烯基提供了重要的见解，揭示了一种奇特的硅化学。
