Silicon-silicon π single bond
Silicon-silicon π single bond
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DOI：
10.1038/s41467-020-17815-z
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发表时间：
2020-08-11
影响因子：
16.6
通讯作者：
Matsumoto, Hideyuki
中科院分区：
文献类型：
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作者：
Kyushin, Soichiro;Kurosaki, Yoshikuni;Matsumoto, Hideyuki
碳-碳双键由一个σ键和一个键组成。最近，在含有碳和杂原子自由基中心的双自由基中提出了π单键的概念，其中π键不伴随有σ键。在这里，我们报道了一种具有硅-硅π单键的闭壳化合物。 1,2,2,3,4,4-六-叔丁基双环[1.1.0]四硅烷在桥头硅原子之间具有硅-硅π单键。 X射线晶体分析表明，硅-硅π单键（2.853(1)埃）远长于迄今为止报道的最长硅-硅键。尽管键长异常长，但 3p 轨道的电子是配对的，这一点通过电子顺磁共振测量、磁化率和自然键轨道分析得到了证实。通过UV/Vis和Si-29 NMR光谱以及理论计算研究了硅-硅π单键的性质。双自由基中 pi 单键的例子很少见，因为它们通常不稳定。在这里，作者描述了一种室温稳定的闭壳双环四硅烷，其特征是两个不相邻的 Si 中心之间有一个 Si-Si pi 单键。
A carbon-carbon double bond consists of a sigma bond and a bond. Recently, the concept of a pi single bond, where a pi bond is not accompanied by a sigma bond, has been proposed in diradicals containing carbon and heteroatom radical centers. Here we report a closed-shell compound having a silicon-silicon pi single bond. 1,2,2,3,4,4-Hexa-tert-butylbicyclo[1.1.0]tetrasilane has a silicon-silicon pi single bond between the bridgehead silicon atoms. The X-ray crystallographic analysis shows that the silicon-silicon pi single bond (2.853(1) angstrom) is far longer than the longest silicon-silicon bond so far reported. In spite of this unusually long bond length, the electrons of the 3p orbitals are paired, which is confirmed by measurement of electron paramagnetic resonance, and magnetic susceptibility and natural bond orbital analysis. The properties of the silicon-silicon pi single bond are studied by UV/Vis and Si-29 NMR spectroscopy, and theoretical calculations. Examples of pi single bonds in diradicals are rare, as they are typically unstable. Here, the authors describe a room temperature-stable closed-shell bicyclic tetrasilane that features a Si-Si pi single bond between two of the non-adjacent Si centers.