Abstract

The electron density distributions obtained by the quantum-chemical (density functional theory) calculations and molecular invariom model in the trimeric ytterbium complex with the hexafluoroisopropoxide ligands {\({\text{Yb}}_{{\text{2}}}^{{{\text{II}}}}\)(μ₂-OR)₃(μ₃-OR)₂Yb^III(OR)₂(THF)(Et₂O)} (I) (where R is CH(CF₃)₂, and THF is tetrahydrofuran) are compared. The main topological characteristics of the electron density at the critical points (3, –1) corresponding to the interactions of the ytterbium atoms in the coordination sphere obtained using two studied approaches demonstrate excellent agreement. The maximum divergence between the density functional calculations and molecular invariom model is observed for the intramolecular interactions involving the fluorine atoms (F···F, F···H, and F···O) in the structure of complex I. Geometry optimization leads to a higher number of these interactions in the complex. The energy corresponding to these interactions also increases. However, the main topological characteristics for the F···X interactions (X = F, H, O), which can be localized in the framework of both methods, remain within the transferability index range. An analysis of the deformation electron density shows that the F^δ–···F^δ– interactions are determined by the correspondence of the region of electron density concentration on one of the fluorine atoms to the region of electron density depletion on the second fluorine atom regardless of the method of measuring the electron density distribution.

中文翻译：

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分子不变模型在{$$ {\ text {Yb}} _ {{\ text {2}}} ^ {{{\ text {II}}}} $$中涉及氟原子相互作用的研究中的应用（μ2 -OCH（CF 3）2）3（μ3 -OCH（CF 3）2）2 Yb III（OCH（CF 3）2）2（THF）（Et 2 O）}络合物

摘要

通过具有六氟异丙氧基配体{ \（{\ text {Yb}} _ {{\ text {2}}} ^的三聚体complex配合物，通过量子化学（密度泛函理论）计算和分子不变模型获得的电子密度分布。 {{{\文本{II}}}} \）（μ ₂ -OR）₃（μ ₃ -OR）₂镱^III（OR）₂（THF）（ET ₂ O）}（我）（其中R是CH （CF ₃）₂，和THF为四氢呋喃）进行比较。使用两种研究方法获得的对应于the原子在配位球体相互作用的临界点（3，–1）处电子密度的主要拓扑特征。对于配合物I结构中涉及氟原子（F··F，F··H和F··O）的分子内相互作用，观察到密度泛函计算与分子不变模型之间的最大差异。。几何优化导致复合物中这些相互作用的数量增加。与这些相互作用相对应的能量也增加了。但是，可以在两种方法的框架中定位的F·X相互作用的主要拓扑特征（X = F，H，O）仍在可传递性指数范围内。对变形电子密度的分析表明，F ^δ– ··· ^Fδ-相互作用是由一个氟原子上的电子密度浓度区域与第二个氟原子上的电子密度耗尽区域的对应关系决定的不管测量电子密度分布的方法如何。