Application of the Molecular Invariom Model for the Study of Interactions Involving Fluorine Atoms in the {{text{Yb}}_{{text{2}}}^{{{text{II}}}}(\u03bc2-OCH(CF3)2)3(\u03bc3-OCH(CF3)2)2YbIII(OCH(CF3)2)2(THF)(Et2O)} Complex

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)2YbIII(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 Fδ–···Fδ– 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.