Holzner Richard, Porzelt Amelie, Karaca Uhut S, Kiefer Fiona, Frisch Philipp, Wendel Daniel, Holthausen Max C, Inoue Shigeyoshi
Department of Chemistry, Catalysis Research Center and Institute of Silicon Chemistry, Technische Universität München, Lichtenbergstraße 4, 85748 Garching bei München, Germany.
Institute for Inorganic and Analytical Chemistry, Goethe-Universität Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt am Main, Germany.
Dalton Trans. 2021 Jun 29;50(25):8785-8793. doi: 10.1039/d1dt01629f.
Two novel disilenes of type ABSi[double bond, length as m-dash]SiAB bearing N-heterocyclic imino (A = NItBu) and trialkylsilyl (B = SitBu31, B = SitBu2Me 2) groups are reported. The reduced steric demand in 2 results in a highly stable, nonetheless flexible system, wherefore (E/Z) isomerization is observed from room temperature up to 90 °C. The proposed isomerization mechanism proceeds via monomeric silylenes in line with experimental results. Despite enhanced stability, disilene 2 retains high reactivity in the activation of small molecules, including H2. The rare example of a disilene radical cation 7 is isolated and shows reversible redox behavior. White phosphorous (P4) selectively reacts with 2 to give the unique cage-compound 8. Selective thermal rearrangement of 2 at higher temperatures yields the A2Si[double bond, length as m-dash]SiB2-type disilene 9 (A = NItBu, B = SitBu2Me), which bears characteristics of a zwitterionic and a dative central Si-Si bond. The proposed mechanism proceeds via an initial NHI migration followed by silyl migration.
报道了两种新型的ABSi=SiAB型二硅烯，其带有N-杂环亚氨基（A = NItBu）和三烷基硅基（B = SitBu31，B = SitBu2Me 2）基团。2中空间位阻需求的降低导致了一个高度稳定但仍具柔性的体系，因此在室温至90°C范围内观察到（E/Z）异构化。所提出的异构化机理与实验结果一致，通过单体硅烯进行。尽管稳定性增强，但二硅烯2在小分子（包括H2）的活化中仍保持高反应活性。分离出了罕见的二硅烯自由基阳离子7的例子，其显示出可逆的氧化还原行为。白磷（P4）与2选择性反应生成独特的笼状化合物8。2在较高温度下的选择性热重排产生了A2Si=SiB2型二硅烯9（A = NItBu，B = SitBu2Me），其具有两性离子和配位中心Si-Si键的特征。所提出的机理通过最初的NHI迁移，随后是硅基迁移进行。
