Synthesis of Novel Silicon-containing Multiple-bond Compounds by Taking Advantage of Steric Protection and Investigation of Their Structures and Reactivities

1.通过四硫硅烷TbT(TiP)SiS_4在正己烷中的脱硫化反应，成功地合成了第一个稳定的硅硫酮TbT(TiP)Si=S(1：Tbt=2，4，6-tris[bis(trimethylsilyl)methyl]phenyl，TiP=2，4，6-三异丙基苯基)。硅硫酮1为稳定的黄色晶体，其核磁共振谱在+166.6ppm(C_6D_6)处有一个特征的下场移位信号，暗示了中心硅的sp^2特征。X-射线晶体结构分析表明，1的硅-S键长比典型的硅-硅单键化合物短约9%，并且1的硅硫羰基单元与酮一样具有完全的三角平面构型。发现硅硫酮1在中心硅原子周围有足够的空间与小分子反应，尽管1的硅原子上的大体积取代基有效地阻止了它的自二聚化。2.稳定的硅酮亚胺的合成，TBT(MES)Si=C…More=NAR，也被空间保护的硅烯TBT(MES)Si：(MES=均三甲基)的反应所验证，该反应在相应的二硅烯TBT(MES)Si=Si(MES)TBT与几种含有大量芳香族取代基的异氰化物的热分解中很容易获得。对得到的蓝色或绿色蓝色浆料的光谱研究表明，所获得的异氰化物的硅烯加合物不是累积的双键物种，而是新型的硅烯-异氰酸酯络合物。3.在本研究的基础上，合成了锗与较重硫原子之间的双键物种，并利用Tbt(Dip)Si=Se(Dip=2，6-diisopropyl-phenyl)stable基团实现了Ge与重硫原子之间的双键物种的动力学稳定，即Ge(R)Ge=X[X=S，Se，Te；R=TiP或CH(SiMe_3)_2]。这些结果已部分作为参考文献中列出的论文发表。较少

1.The first stable silanethione Tbt(Tip)Si=S(1 : Tbt=2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, Tip=2,4,6-triisopropylphenyl)was successfully synthesized by the desulfurization of the corres-ponding tetrathiasilolane, Tbt(Tip)SiS_4, with triphenylphoshine in hexane. Silanethione 1 was isolated as stable yellow crystals and it showed a characteristic downfield shifted signal at+166.6ppm(in C_6D_6)in the ^<29>Si NMR spectra suggesting the sp^2 character of the central silicon. The X-ray crystallographic structural analysis revealed that the Si-S bond length of 1 is ca. 9% shorter than that of the typical Si-Si single bond compounds and the silathiocarbonyl unit of 1 has a completely trigonal planar geometry as in the case of ketones. Silinethione 1 was found to have an enough space around the central siliconatom to react with small molecules, though the bulky substituents on Si atom of 1 effectively prevent its self-dimerization.2.The synthesis of a stable silaketeneimine, Tbt(Mes)Si=C … More =NAr, was also examined by the reaction of a sterically protected silylene Tbt(Mes)Si : (Mes=mesityl), which was found to be readily available on the thermolysis of the corresponding disilenes Tbt(Mes)Si=Si(Mes)Tbt, with several kinds of isocyanides bearing bulky aromatic substituents. The spectroscopic investigation on the resulting blue or greenish blue pastes revealed that the silylene adducts of isocyanides here obtianed were not the cumulative double-bond species but the novel silylene-isocyanide complexes. This is the first examples of isolated silyene-Lewis base complexes.3.The thermal reaction of an overcrowded silascylopropane derivative in the presence of elemental selenium resulted in the formation of silaneselone Tbt(Dip)Si=Se(Dip=2,6-diisopropyl-phenyl)stable in solution.As an extension of this research project, the double-bond species between germanium and heavier chalcogen atoms kinetically stablilized by taking advantage of the Tbt group, i.e.germanethiones, germaneselones, and germanetellones Tbt(R)Ge=X[X=S,Se, Te ; R=Tip or CH(SiMe_3)_2], were all synthesized and isolated as stable crystalline compounds. These results have been partially published as papers listed in the references. Less