Faculty of Chemistry, University of the Basque Country and Donostia International Physics Center (DIPC), P.K. 1072, 20080 Donostia, Spain.
IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain.
Molecules. 2018 May 15;23(5):1183. doi: 10.3390/molecules23051183.
MP2/aug-cc-pVTZ calculations were carried out for the ZFH₃-B complexes (Z = C, Si, Ge, Sn and Pb; B = C₂H₂, C₂H₄, C₆H₆ and C₅H₅⁻; relativistic effects were taken into account for Ge, Sn and Pb elements). These calculations are supported by other approaches; the decomposition of the energy of interaction, Quantum Theory of Atoms in Molecules (QTAIM) and Natural Bond Orbital (NBO) method. The results show that tetrel bonds with π-electrons as Lewis bases are classified as Z···C links between single centers (C is an atom of the π-electron system) or as Z···π interactions where F‒Z bond is directed to the mid-point (or nearly so) of the CC bond of the Lewis base. The analogous systems with Z···C/π interactions were found in the Cambridge Structural Database (CSD). It was found that the strength of interaction increases with the increase of the atomic number of the tetrel element and that for heavier tetrel elements the ZFH₃ tetrahedral structure is more deformed towards the structure with the planar ZH₃ fragment. The results of calculations show that the tetrel bond is sometimes accompanied by the Z-H···C hydrogen bond or even sometimes the ZFH₃-B complexes are linked only by the hydrogen bond interaction.
采用 MP2/aug-cc-pVTZ 方法对 ZFH₃-B（Z = C、Si、Ge、Sn 和 Pb；B = C₂H₂、C₂H₄、C₆H₆ 和 C₅H₅⁻；其中 Ge、Sn 和 Pb 元素考虑相对论效应）复合物进行了计算。这些计算得到了其他方法的支持，包括相互作用能分解、分子中的原子量子理论（QTAIM）和自然键轨道（NBO）方法。结果表明，作为路易斯碱的具有π 电子的四配位键被分类为单中心的 Z···C 键（C 是π 电子体系的原子）或 F‒Z 键指向路易斯碱 CC 键中点（或几乎如此）的 Z···π 相互作用。在剑桥结构数据库（CSD）中发现了具有 Z···C/π 相互作用的类似体系。结果表明，相互作用强度随着四配位元素原子序数的增加而增加，对于较重的四配位元素，ZF₃四面体结构向具有平面 ZH₃片段的结构变形更大。计算结果表明，四配位键有时伴随着 Z-H···C 氢键，甚至有时 ZFH₃-B 复合物仅通过氢键相互作用连接。
