Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan.
Proc Jpn Acad Ser B Phys Biol Sci. 2012;88(5):167-91. doi: 10.2183/pjab.88.167.
Structure and properties of silicon-silicon doubly bonded compounds (disilenes) are shown to be remarkably different from those of alkenes. X-Ray structural analysis of a series of acyclic tetrakis(trialkylsilyl)disilenes has shown that the geometry of these disilenes is quite flexible, and planar, twist or trans-bent depending on the bulkiness and shape of the trialkylsilyl substituents. Thermal and photochemical interconversion between a cyclotetrasilene and the corresponding bicyclo[1.1.0]tetrasilane occurs via either 1,2-silyl migration or a concerted electrocyclic reaction depending on the ring substituents without intermediacy of the corresponding tetrasila-1,3-diene. Theoretical and spectroscopic studies of a stable spiropentasiladiene have revealed a unique feature of the spiroconjugation in this system. Starting with a stable dialkylsilylene, a number of elaborated disilenes including trisilaallene and its germanium congeners are synthesized. Unlike carbon allenes, the trisilaallene has remarkably bent and fluxional geometry, suggesting the importance of the π-σ* orbital mixing. 14-Electron three-coordinate disilene-palladium complexes are found to have much stronger π-complex character than related 16-electron tetracoordinate complexes.
硅-硅双键化合物（二硅烯）的结构和性质与烯烃显著不同。一系列无环四（三烷基硅基）二硅烯的 X 射线结构分析表明，这些二硅烯的几何形状非常灵活，可以是平面、扭曲或反式弯曲，具体取决于三烷基硅基取代基的体积和形状。环四硅烯和相应的双环[1.1.0]四硅烷之间的热和光化学互变可以通过 1,2-硅迁移或协同电环化反应发生，具体取决于环取代基，而无需经过相应的四硅-1,3-二烯中间体。稳定的螺戊二硅杂戊二烯的理论和光谱研究揭示了该体系中螺共轭的独特特征。从稳定的二烷基硅烯出发，合成了包括三硅烯丙二烯及其锗同系物在内的多种复杂二硅烯。与碳丙二烯不同，三硅烯丙二烯具有显著弯曲和易变的几何形状，表明π-σ*轨道混合的重要性。发现 14 电子三配位二硅烯-钯配合物具有比相关的 16 电子四配位配合物更强的π-配合物特征。
