Conformational Properties of 1-Halogenated-1-Silacyclohexanes, C<sub>5</sub>H<sub>10</sub>SiHX (X = Cl, Br, I): Gas Electron Diffraction, Low-Temperature NMR, Temperature-Dependent Raman Spectroscopy, and Quantum-Chemical Calculations
作者:Sunna Ó. Wallevik、Ragnar Bjornsson、Ágúst Kvaran、Sigridur Jonsdottir、Ingvar Arnason、Alexander V. Belyakov、Thomas Kern、Karl Hassler
DOI:10.1021/om4005725
日期:2013.12.9
the thermodynamic equilibrium between these species was investigated by means of gas electron diffraction, dynamic nuclear magnetic resonance, temperature-dependent Raman spectroscopy, and quantum-chemical calculations applying CCSD(T), MP2, and DFT methods. According to the experimental and calculated results, all three compounds exist as a mixture of two chair conformers of the six-membered ring. The
的轴向和赤道构象异构体的分子结构环-C 5 H ^ 10 SiHX(X =氯,溴,I)以及这些物质之间的热力学平衡用气相电子衍射的方法研究,动态核磁共振,温度相关拉曼光谱,以及应用 CCSD(T)、MP2 和 DFT 方法的量子化学计算。根据实验和计算结果,所有三种化合物均以六元环的两种椅式构象异构体的混合物形式存在。C的两种椅子形式X 原子的轴向或赤道位置的对称性不同。在所有情况下,轴向构象异构体优于赤道构象异构体。当考虑到实验的不确定性时,构象能(E轴- E赤道)的所有实验和理论结果都适合 -0.50 ± 0.15 kcal mol –1的非常窄的范围。NBO分析发现轴向构象异构体在空间能和共轭效应方面是不利的,它们主要通过静电相互作用稳定。C 6 H 11 X 和环-C 5 H 10的构象能SiHX (X = F, Cl, Br, I, At) 使用 CCSD(T) 计算进行比较。在