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Syntheses and Properties of Cyclopolysilanes with Well-defined Structures as Models for σ-Conjugation

作为 σ 共轭模型的具有明确结构的环聚硅烷的合成和性能

基本信息

批准号：
09304058
负责人：
MATSUMOTO Hideyuki
金额：
$ 25.41万
依托单位：
Gunma University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A).
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 2000
项目状态：
已结题

项目摘要

1. In a series of the anti isomers of the ladder polysilanes, the absorption maxima of the longest wavelength shift to the longer wavelength region as the number of cyclotetrasilane rings progressively increases. The shift is explained in terms of the stabilization of the lowest unoccupied molecular orbitals (LUMO) by the extension of the Si-Si σ-conjugation. The ladder polysilanes can be readily reduced by Na and K to generate the radical anions. The remarkable feature of the resulting radical anions is their unusual stability. For example, in the absence of dioxygen, the half-life of the pentacyclododecasilane is too long to be measured. The X-ray crystallography disclosed that the anti ladder polysilanes can be seen as silicon double helices, in which two linear polysilane chains screw in one way and are bridged by Si-Si bonds. Chiral symmetry breaking could be realized for anti-tricyclooctasilane. The crystallization gave one large crystal of each enantiomer M or P.The oxidation of … More the bicyclohexasilane with a deficient amount of m-chloroperbenzoic acid (MCPBA) resulted in the formation of 7-oxa compound, which shows stronger UV absorption and fluorescence. The domino oxidation predominates in the tri-, tetra-, and penta-oxidations of the tricyclooctasilane, tetracyclodecasilane, and pentacyclododecasilane with MCPBA, respectively.2. From the stereochemical results observed in the ring-opening of the cis, cis- and cis, transcyclotrisilane [Ph (Thex) Si]_3 (Thex=1, 1, 2-trimethylpropyl) with halogens, it is concluded that the cleavage of the Si-Si bonds occurs with retention -inversion of the configuration of the Si atoms.3. Octathexyloctagermacubane was synthesized to allow a comparison of chemical and physical properties of the alkyl-substituted octasilacubane with those of the corresponding octagermacubane. The octagermacubane is very stable to UV-Visible light, suggesting the unusual electronic and photochemical properties of the polyhedral germanium framework. Less

1.在梯形聚硅烷的一系列反式异构体中，随着环四硅烷环的数目逐渐增加，最长波长的吸收最大值向较长波长区域偏移。这种位移可以用Si-Si σ-共轭的扩展稳定了最低未占分子轨道（LUMO）来解释。梯形聚硅烷可以容易地被Na和K还原以产生自由基阴离子。由此产生的自由基阴离子的显着特点是它们不寻常的稳定性。例如，在不存在分子氧的情况下，五环十二硅烷的半衰期太长而无法测量。X射线晶体学研究表明，反梯形聚硅烷是由两条聚硅烷链单向螺旋，通过Si-Si键桥接而成的硅双螺旋结构。反式三环辛硅烷可以实现手性对称性破缺。结晶得到每种对映异构体M或P的一个大晶体。 ...更多信息双环己硅烷与少量的间氯过苯甲酸（MCPBA）导致形成7-氧杂化合物，其显示出更强的紫外吸收和荧光。三环辛硅烷、四环十硅烷和五环十二硅烷与MCPBA的三氧化、四氧化和五氧化反应均以多米诺氧化为主.从顺式，顺式和顺式，反式环三硅烷[Ph（Thex）Si]_3（Thex=1，1，2-三甲基丙基）与卤素开环反应的立体化学结果可以推断，Si-Si键的断裂伴随着Si原子构型的保留-反转.合成了八乙基辛麦角立方烷，以比较烷基取代的八硅立方烷与相应的八麦角立方烷的化学和物理性质。八角形立方烷对紫外-可见光非常稳定，这表明多面体锗骨架具有不寻常的电子和光化学性质。少