Wann Derek A, Rataboul Franck, Reilly Anthony M, Robertson Heather E, Lickiss Paul D, Rankin David W H
School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh, UKEH9 3JJ.
Dalton Trans. 2009 Sep 14(34):6843-8. doi: 10.1039/b909136j. Epub 2009 Jul 17.
The equilibrium molecular structure of the decasilsesquioxane, Si(10)O(15)H(10), in the gas phase has been determined by gas electron diffraction. Molecular dynamics calculations were used to give amplitudes of vibration and differences between interatomic distances in the equilibrium structure and the vibrationally averaged distances that are given directly by the diffraction data. The molecules have D(5h) symmetry, and do not show the distortions that are apparent in the crystalline phase. The ten-membered silicon-oxygen rings are found to be particularly flexible in the gas phase, a phenomenon that was also seen in crystal structures. The Si-O bond lengths in the ten-membered rings are 161.6(2) pm long and in the eight-membered rings they are 162.2(3) pm, with Si-O-Si angles of 155.0(5) and 153.9(7) degrees , respectively.
通过气体电子衍射确定了气相中十硅倍半氧烷Si(10)O(15)H(10)的平衡分子结构。利用分子动力学计算得出了平衡结构中振动幅度以及原子间距离与直接由衍射数据给出的振动平均距离之间的差异。这些分子具有D(5h)对称性，且未表现出在晶相中明显的畸变。发现十元硅氧环在气相中特别灵活，这种现象在晶体结构中也可见。十元环中的Si - O键长为161.6(2)皮米，八元环中的Si - O键长为162.2(3)皮米，Si - O - Si角分别为155.0(5)度和153.9(7)度。
