Reaction Control of Dynamic Complexes with Multiple Bonds of Heavy Group-14 Elements

在2002-2004年间，我们致力于创造新型重14族元素的双键化合物，阐明它们的结构和性质，并控制它们独特的动力学性质。主要成果如下：作为第一个具有5P杂化硅原子的化合物，我们在1999年合成了一个稳定的硅烯化合物。合成了相应的三烯丙烯、β-二硅杂烯丙烯和β-二硅杂烯丙烯。对这些联烯的X射线分析表明，与碳联烯相比，它们都有明显弯曲的骨架。作为最显著的动力学行为，三硅拉烯和β-二硅铝烯表现出中心重基团-14原子随温度变化的动力学无序。对这一动态过程的详细研究从实验和理论上揭示了这一过程是由中心原子绕末端两个硅原子的灵活旋转所解释的。在三马来烯和β-diermasilaallene中没有观察到动力学无序，这是因为末端Ge原子发生了严重的弯曲。以稳定的二烷基硅烯为原料，合成了热稳定性较好的硅硫族双键化合物(硅硫酮、硅烷酮和硅烷酮)。首次系统地分析了一系列硅-硫族双键化合物的X射线和紫外可见光谱，揭示了双键强度和nπ^*和nπ^*吸收带与元素的关系。通过X-射线分析和理论计算发现，由双膦钯与稳定的二硅烯反应合成的第一个14电子的二硅烯-钯配合物具有很强的JX-二硅烯络合物的性质。

During the period of 2002-2004, our study was directed toward the creation of new types of doubly bonded compounds of heavier group-14 element, elucidation of their structure and properties, and control of their unique dynamic properties. The following are the major achievements : As the first compound having formally 5p-hybridized silicon atom, a stable trisilaallene was synthesized using a stable silylene that was synthesized by us in 1999. Related trigermaallene, β-digerrnasilaallene, and β-disilagermaallene were also synthesized. X-ray analysis of these allenes has shown tot in contrast to carbon allenes, all of them have a significantly bent skeleton. As the most remarkable dynamic behavior, trisilaallene and β-disilagermaallene showed temperature dependent dynamic disorder of the central heavy grouo-14 atom. The detailed investigation of the dynamic process both experimentally and theoretically revealed that the process is explained by the facile rotation of the central atom around the terminal two silicon atoms. The dynamic disorder was not observed in the trigermaallene and β-digermasilaallene because of the severe bending at the terminal germanium atoms. Thermally stable silicon-chalcogen doubly bonded compounds (silanethione, silaneseleone, and silanetellone) were synthesized, using our stable dialkylsilylene. The first systematic analysis of the X-ray and UV-vis spectra of a series of silicon-chalcogen doubly bonded compounds revealed the element dependence of the strength of the double bonds and n π^* and n π^* absorption bands. The first 14-electron disilene-palladium complex that was synthesized by the reaction of a bis (phosphine) palladium with a stable disilene was found by the X-ray analysis and theoretical calculations to have the strong jx-disilene complex character.