Electronic structures of a series oflanthanide complexes with hexafluoroisopropoxide ligands [Ln(OCH(CF3)2)2(μ2-OCH(CF3)2)(DME)]2 (Ln = Ce, Sm, Tm, Yb; DME is dimethoxyethane) were studied by quantum chemical calculations at the density functional theory (DFT) level. Intramolecular C-F→Ln interactions are present in all these compounds. A decrease in the ionic radius of lanthanide in the series from Ce to Yb leads to an increase in the degree of filling of the coordination sphere from 92.9(2) to 97.3(2)%, resulting in a systematic decrease in the delocalization index between lanthanide and fluorine atoms. An experimental-theoretical study of the complexes using a molecular invariom provided an estimate of the energy of Ln⋯F interactions, which also decreases for the complexes of the late lanthanides (Tm, Yb) compared with the complexes of the early lanthanides (Ce, Sm). Geometry optimization of the isolated molecule leads to an increase in the number of non-covalent interactions involving fluorine atoms (F⋯F, F⋯H, and F⋯O) and in their energy compared to the molecular invariom. The topological characteristics of electron density in the coordination sphere of lanthanide atoms determined by quantum chemical calculations are in good agreement with those estimated using the molecular invariom.

中文翻译：

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镧系元素的性质对六氟异丙氧化物配合物中分子内CF→Ln配位相互作用的影响

一系列具有六氟异丙醇配体的镧系元素配合物 [Ln(OCH(CF3)2)2(μ2-OCH(CF3)2)(DME)]2（Ln = Ce、Sm、Tm、Yb；DME 是二甲氧基乙烷）的电子结构为通过密度泛函理论 (DFT) 级别的量子化学计算进行研究。所有这些化合物中都存在分子内 CF→Ln 相互作用。从 Ce 到 Yb 的系列中镧系元素离子半径的减小导致配位球的填充度从 92.9(2)% 增加到 97.3(2)%，导致离域指数在镧系元素和氟原子。使用分子不变量对配合物进行的实验理论研究提供了对 Ln⋯F 相互作用能量的估计，对于晚期镧系元素 (Tm, Yb) 与早期镧系元素 (Ce, Sm) 的配合物相比。与分子不变量相比，孤立分子的几何优化导致涉及氟原子（F⋯F、F⋯H 和 F⋯O）的非共价相互作用的数量及其能量的增加。通过量子化学计算确定的镧系原子配位球中电子密度的拓扑特征与使用分子不变量估计的拓扑特征非常吻合。