Pokhodnya Konstantin, Anderson Kenneth, Kilina Svetlana, Boudjouk Philip
Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108, United States.
J Phys Chem A. 2017 May 11;121(18):3494-3500. doi: 10.1021/acs.jpca.6b12938. Epub 2017 May 1.
We report the detailed computational study of flattening of the puckered Si ring by suppression of the pseudo-Jahn-Teller (PJT) effect through coordination of two Cl anions to the molecule forming an inverse sandwich dianion [SiCl·2Cl] complex. The PJT effect that causes nonplanarity of the SiCl structure (C) results from vibronic coupling of pairs of occupied molecular orbitals (OMOs) and unoccupied molecular orbitals (UMOs). It was shown that filling the intervenient molecular orbitals of puckered SiCl with valent electron pairs of Cl donors suppresses the PJT effect, with the Si ring becoming planar (D) upon complex formation. In this paper, the stabilization energy E(2) associated with donor-acceptor charge transfer (delocalization) was estimated using NBO analysis for all studied inverse sandwich compounds [SiCl·2X] (where X = F, Cl, Br). It was found that the polarizability of the donor ion might significantly affect the stabilization energy value and should be taken into account when choosing the ligands suitable for forming Si-based one-dimensional compounds and other nanoscale materials.
我们报道了通过两个Cl阴离子与分子配位形成反夹心二价阴离子[SiCl·2Cl]配合物来抑制赝 Jahn-Teller（PJT）效应，从而使褶皱的Si环变平的详细计算研究。导致SiCl结构（C）非平面性的PJT效应是由占据分子轨道（OMO）对与未占据分子轨道（UMO）的振动耦合引起的。结果表明，用Cl供体的价电子对填充褶皱SiCl的中间分子轨道可抑制PJT效应，形成配合物时Si环变为平面（D）。在本文中，使用NBO分析对所有研究的反夹心化合物[SiCl·2X]（其中X = F、Cl、Br）估算了与供体-受体电荷转移（离域）相关的稳定能E(2)。结果发现，供体离子的极化率可能会显著影响稳定能值，在选择适合形成硅基一维化合物和其他纳米级材料的配体时应予以考虑。
