Iwamoto Takeaki, Abe Takashi, Sugimoto Kunihisa, Hashizume Daisuke, Matsui Hiroshi, Kishi Ryohei, Nakano Masayoshi, Ishida Shintaro
Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai, 980-8578, Japan.
Japan Synchrotron Radiation Research Institute (JASRI), Sayo-gun, Hyogo, 679-5148, Japan.
Angew Chem Int Ed Engl. 2019 Mar 22;58(13):4371-4375. doi: 10.1002/anie.201900824. Epub 2019 Feb 21.
Bicyclo[1.1.0]tetrasil-1(3)-ene 1, a tetrasilicon analogue of bicyclo[1.1.0]but-1(3)-ene that contains a formal double bond between bridgehead silicon atoms in an inverted geometry, was synthesized and isolated in the form of thermally stable orange crystals. The distance between the bridgehead Si atoms in 1 is much longer than those in typical Si=Si bonds, but still shorter than that of a previously reported pentasila[1.1.1]propellane. DFT calculations suggest that the bridgehead bond in 1 comprises a σ bond with an inverted geometry and a π bond. This notion is supported by the UV/Vis spectrum of 1, which exhibits several absorption bands in the UV/Vis region. While 1 is stable toward typical trapping agents for Si=Si double bonds, 1 reacts with carbon tetrachloride to furnish a hexachlorotetrasilane.
双环[1.1.0]四硅-1(3)-烯1，是双环[1.1.0]丁-1(3)-烯的四硅类似物，在桥头硅原子之间含有一个呈反式几何构型的形式双键，已被合成并以热稳定的橙色晶体形式分离出来。1中桥头硅原子之间的距离比典型的Si=Si键中的距离长得多，但仍比先前报道的五硅[1.1.1]丙搭烯中的距离短。密度泛函理论计算表明，1中的桥头键由一个呈反式几何构型的σ键和一个π键组成。这一观点得到了1的紫外/可见光谱的支持，该光谱在紫外/可见区域呈现出几个吸收带。虽然1对典型的Si=Si双键捕获剂稳定，但1与四氯化碳反应生成六氯四硅烷。
