On the presence or absence of geminal Si⋯N interactions (α-effect) in pentafluorophenylsilyl compounds with SiCN, SiNN and SiON backbones
作者:Markus Woski、Raphael J. F. Berger、Norbert W. Mitzel
DOI:10.1039/b808388f
日期:——
The silanes C6F5SiF2CH2NMe2 (1), C6F5SiF2N(SiMe3)NMe2 (2) and C6F5SiF2ONMe2 (3) with pentafluorophenyl substituents and geminal N atoms have been prepared by the reaction of C6F5SiF3 with LiCH2NMe2, LiN(SiMe3)NMe2 and LiONMe2, respectively. The compounds have been characterised by spectroscopic methods and crystal structure determination. Comparison of measured and calculated IR spectra has provided insight into the conformational composition of the vapour of 3. Whereas 2 and 3 show interactions between the geminal Si and N atoms, 1 does not. Further analysis of the bonding situation has been undertaken by quantum chemical calculations of the rotation and bending potentials of the C6F5SiF2âXâNMe2 units.
通过C6F5SiF3分别与LiCH2NMe2、LiN(SiMe3)NMe2和LiONMe2反应制备了带有五氟苯基取代基和偕N原子的硅烷C6F5SiF2CH2NMe2 (1)、C6F5SiF2N(SiMe3)NMe2 (2)和C6F5SiF2ONMe2 (3)。这些化合物已通过光谱方法和晶体结构测定进行了表征。测量和计算的红外光谱的比较提供了对 3 的蒸气构象组成的深入了解。虽然 2 和 3 显示了孪晶 Si 和 N 原子之间的相互作用,但 1 没有。通过对 C6F5SiF2-X-NMe2 单元的旋转和弯曲势的量子化学计算,对键合情况进行了进一步分析。