[Sn4Si{Si(SiMe3)3}4{SiMe3}2]: a model compound for the unexpected first-order transition from a singlet biradicaloid to a classical bonded molecule.
[Sn4Si{Si(SiMe3)3}4{SiMe3}2]: a model compound for the unexpected first-order transition from a singlet biradicaloid to a classical bonded molecule.
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[Sn4Si{Si(SiMe3)3}4{SiMe3}2]：用于从单线态双自由基到经典键合分子的意外一级转变的模型化合物
DOI：
10.1002/anie.201102662
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发表时间：
2011
影响因子：
--
通讯作者：
A. Schnepf
中科院分区：
文献类型：
--
作者：
C. Schrenk;A. Kubas;K. Fink;A. Schnepf
通式为MnRm（n> m; M=金属或半金属，R=配体）的类金属簇合物是分子和固态所涵盖的系统尺寸范围的理想模型化合物，为进一步理解原子尺度上从氧化物质形成元素铺平了道路。[1]在锡的情况下，类金属簇合物首先通过SnII化合物（例如SnCl 2）的还原偶联来合成。[2]最近的研究表明，锡的类金属簇合物也可以通过卤化锡的缩合反应合成。[3]由此通过采用制备共缩合技术获得单卤化物。[4]因此，SnBr与LiSi（SiMe 3）3的反应以约17%的中等产率产生准金属簇化合物[Sn 10 {Si（SiMe 3）3} 6]（1）。[5]因为1中的十个锡原子中只有六个带有Si（SiMe 3）3配体，所以锡原子的平均氧化态为0.6。因此，准金属簇1是在形成元素锡的过程中的还原反应的还原产物。[6]由于反应从一卤代SnBr开始，因此反应溶液中也必须存在平均锡原子氧化态大于1的氧化物质。这种化合物的早期例子是阴离子亚锡烷基[Sn {Si（SiMe 3）3} 3] 3和环三锡烷基[Sn 3 {Si（SiMe 3）3} 4]（2），其中锡原子的平均氧化态分别为+2和+1.3。[7]在2中观察到最短的锡-锡双键为258 pm，这是由于配体的空间体积迫使双键进入平面排列造成的。由于2仅与类金属簇合物[Sn 10 {Si（SiMe 3）3} 6]（1）一起获得，因此对2的后续研究总是受到1的存在的阻碍。尝试从反应混合物中结晶2以避免该问题。在这些尝试中，获得了另一种类型的黑色钻石状晶体，这些晶体的单晶X射线衍射分析揭示了一种未知的晶体系统。然而，晶体结构的解表明，准金属簇化合物1存在于晶格中，[8]这次与新的多面体簇化合物[Sn 4Si {Si-（SiMe 3）3} 4（SiMe 3）2]（3）一起结晶。3的分子结构最好描述为由Si（SiMe 3）2基团桥接的四个锡原子的蝴蝶排列（图1）。每个锡原子额外地结合到Si（SiMe 3）3配体，具有稍微不同的Sn-Si距离261 μ m（Sn 11-Si 7A，Sn 13-Si 7）和265 μ m（Sn 14-Si 8，Sn 12-Si 8A）。封端Si（SiMe 3）2基团最有可能来自Si（SiMe 3）3配体的降解，并且在支持信息中给出了合理的机制。
Metalloid cluster compounds of the general formula MnRm (n> m; M= metal or semi-metal, R= ligand) are ideal model compounds for the system size range encompassed by molecules and the solid state, paving the way for further understanding of element formation from oxidized species on an atomic scale.[1] In the case of tin, metalloid cluster compounds were first synthesized by reductive coupling of SnII compounds, such as SnCl2.[2] Recently it was shown that metalloid cluster compounds of tin can also be synthesized by the disproportionation reaction of tin monohalides.[3] The monohalides are thereby obtained by employing a preparative co-condensation technique.[4] Hence, the reaction of SnBr with LiSi (SiMe3) 3 leads to the metalloid cluster compound [Sn10 {Si (SiMe3) 3} 6](1) in moderate yield of approximately 17%.[5] Because only six of the ten tin atoms in 1 bear a Si (SiMe3) 3 ligand, the average oxidation state of the tin atoms is 0.6. Thus, the metalloid cluster 1 is a reduction product of the disproportionation reaction on the way to elemental tin.[6] Because the reaction starts with the monohalide SnBr, oxidized species with an average tin atom oxidation state of greater than 1 must also be present in the reaction solution. Early examples of such compounds were anionic stannylene [Sn {Si (SiMe3) 3} 3] À and cyclotristannene [Sn3 {Si (SiMe3) 3} 4](2), in which the average oxidation states of the tin atoms is+ 2 and+ 1.3, respectively.[7] The shortest tin–tin double bond of 258 pm was observed in 2, caused by the steric bulk of the ligands forcing the double bond into a planar arrangement. As 2 is only obtained together with the metalloid cluster compound [Sn10 {Si (SiMe3) 3} 6](1), subsequent investigations on 2 are always hindered by the presence of 1. Crystallization of 2 from the reaction mixture was attempted to circumvent this problem. During these attempts, another type of black diamond shaped crystals were obtained, and single crystalX-ray diffraction analysis of these crystals revealed a yet unknown crystal system. However, solution of the crystal structure showed that the metalloid cluster compound 1 is present in the crystal lattice,[8] this time crystallizing together with the novel polyhedral cluster compound [Sn4Si {Si-(SiMe3) 3} 4 (SiMe3) 2](3). The molecular structure of 3 is best described as a butterfly arrangement of four tin atoms bridged by a Si (SiMe3) 2 group (Figure 1). Every tin atom is additionally bound to a Si (SiMe3) 3 ligand, with slightly different Sn–Si distances of 261pm (Sn11–Si7A, Sn13–Si7) and 265pm (Sn14–Si8, Sn12–Si8A). The capping Si (SiMe3) 2 group most likely comes from the degradation of the Si (SiMe3) 3 ligand, and a plausible mechanism is given in the supporting information.
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影响因子：
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影响因子：
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作者：
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影响因子：
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作者：
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影响因子：
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作者：
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通讯作者：
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