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Clarification of the Reduction Behaver of Photoexcited Samarium Species and its Application to the Development of New Synthetic Processes

光激发钐物种还原行为的阐明及其在新合成工艺开发中的应用

基本信息

批准号：
11450347
负责人：
OGAWA Akiya
金额：
$ 2.82万
依托单位：
Nara Women's University (2000)Osaka University (1999)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

It has been revealed that the irradiation with visible light enhances the reducing ability of samarium diiodide. While the reduction of organic fluorides with SmI_2 alone is difficult, irradiation with visible light causes the efficient reduction of organic fluorides to the corresponding hydrocarbons. Next we examined the application of this system to the reductive cleavage of Si-Cl bonds. After lots of effort, the reductive coupling of chlorosilanes is found to take place effectively by using samarium diiodide, samarium metal, and magnesium metal, giving the corresponding disilanes in good yields. Even in the absence of magnesium metal, the reductive dimerization of silyl chlorides proceeds to give the corresponding disilanes in relatively lower yields, whereas the presence of both samarium diiodide and samarium metal is essential. A catalytic amount of samarium diiodide is found to cause reductive coupling of organic tin chlorides and organic germyl chlorides with magnesium metal as a co-reductant efficiently even in the absence of samarium metal. The reduction system of chlorosilanes is successfully applied to the formation of polysilanes. Phenylmethyldichlorosilane is reductively polymerized to produce the polysilane with narrow and normal molecular weight distributon. The UV-visible spectra of polysilanes indicate the absorption based on the σ-conjugation of Si-Si at 340 nm, suggesthg the high purity of polysilanes synthesized by this samarium method. This finding indicates that this polymerization method is of potential for polysilnae synthesis.

结果表明，可见光照射能增强二碘化钐的还原能力。虽然单独用SmI_2还原有机氟化物是困难的，但在可见光照射下，有机氟化物被有效地还原为相应的烃。接下来，我们研究了该系统的应用，以还原裂解的Si-Cl键。经过大量的努力，发现通过使用二碘化钐、金属钐和金属镁，氯硅烷的还原偶联有效地发生，以良好的产率得到相应的二硅烷。即使在不存在镁金属的情况下，甲硅烷基氯化物的还原二聚反应也以相对较低的产率进行，从而得到相应的乙硅烷，而二碘化钐和钐金属两者的存在是必要的。发现催化量的二碘化钐即使在不存在钐金属的情况下也能有效地引起有机氯化锡和有机甲锗烷基氯化物与作为共还原剂的镁金属的还原偶联。氯硅烷的还原体系成功地应用于聚硅烷的形成。采用苯甲基二氯硅烷还原聚合法制备了分子量分布窄、分布正的聚硅烷。聚硅烷的紫外-可见光谱表明，在340 nm处有基于Si-Si σ-共轭的吸收，这与钐法合成的聚硅烷纯度高有关。这一发现表明，这种聚合方法是潜在的聚硅烷合成。