Key Laboratory for Power Machinery and Engineering of Ministry of Education (MOE) , Shanghai Jiao Tong University , Shanghai 200240 , PR China.
Department of Chemistry , University of California , Riverside , California 92521 , United States.
J Phys Chem A. 2019 Dec 12;123(49):10520-10528. doi: 10.1021/acs.jpca.9b08102. Epub 2019 Nov 25.
Thermal decomposition of hexamethyldisilane (HMDS) was studied from room temperature to 1310 K using flash pyrolysis vacuum ultraviolet single-photon ionization time-of-flight mass spectrometry (VUV-SPI-TOFMS). Decomposition pathways of HMDS and initial reaction intermediates were also investigated using density functional theory (DFT) at the B3LYP/6-311++G(d,p) level. Unimolecular decomposition reactions of HMDS involving Si-Si and Si-C bond cleavage, as well as decomposition producing MeSi and :SiMe via a three-centered elimination, were determined as the initiation reactions. MeSiSi(Me), MeSi, MeSi, and :SiMe were major products of the initiation reactions. These initial products were apt to decompose by homolytic reactions. MeSi═CH, :SiMe, and other silene/silylene intermediates preferred decomposing through molecular eliminations. Both homolytic and molecular elimination reactions are important in the pyrolysis of HMDS.
使用闪光热解真空紫外单光子电离飞行时间质谱（VUV-SPI-TOFMS），从室温到 1310 K 研究了六甲基二硅烷（HMDS）的热分解。还使用密度泛函理论（DFT）在 B3LYP/6-311++G（d，p）水平上研究了 HMDS 的分解途径和初始反应中间体。涉及 Si-Si 和 Si-C 键断裂的 HMDS 的单分子分解反应，以及通过三中心消除生成 MeSi 和 :SiMe 的分解，被确定为引发反应。MeSiSi(Me)、MeSi、MeSi 和 :SiMe 是引发反应的主要产物。这些初始产物容易通过均裂反应分解。MeSi═CH、:SiMe 和其他硅烯/硅烷中间体更喜欢通过分子消除分解。均裂和分子消除反应在 HMDS 的热解中都很重要。
