Theoretical predictions on the structure and d-AO-based aromaticity of Re3F32+/0/4−, Re3F3X+ (X = Li, Na, K), and Re3F3Y2+ (Y = Be, Mg, Ca) clusters

Abstract

The electronic structure and chemical bonding in Re₃F₃^2+/0/4− clusters are investigated using density functional theory (DFT) calculations. Out research results show that the ground state for the Re₃F₃^2+/0/4− clusters is found to be triplet state ³A′₁ with the D_3h symmetry, quintet state ⁵A′ with the C_s symmetry, and quintet state ⁵A′₁ with the D_3h symmetry, respectively. A detailed molecular orbital (MO) analysis reveals that the Re₃F²⁺₃ (D_3h, ³A′₁) dication possesses multiple (π_F and partial δ_Re) aromaticity that is respectively responsible for the triangular F₃ framework and the triangular Re₃ framework in the Re₃F²⁺₃ (D_3h, ³A′₁) dication. The neutral Re₃F₃ (C_s, ⁵A′) cluster possesses partial δ-aromaticity that is responsible for the triangular Re3 framework in the Re₃F₃ (C_s, ⁵A′) cluster. The Re₃F⁴⁻₃ (D_3h, ⁵A′₁) anion possesses multiple (σ and partial δ) aromaticity that is responsible for the triangular Re₃ framework in the Re₃F⁴⁻₃ (D_3h, ⁵A′₁) cluster. We also examined their hexagonal pyramidal-type Re₃F₃X⁺ (C_3v, ¹A′₁) (X = Li, Na, K) and Re₃F₃Y²⁺ (C_3v, ¹A′₁) (Y = Be, Mg, Ca) complexes containing the Re₃F₃ (D_3h, ¹A′₁) ligand to reveal that the Re₃F₃ (C_3h, ¹A′₁) structural unit is perfectly preserved in these Re₃F₃X⁺ (C_3v, ¹A′₁) and Re₃F₃Y²⁺ (C_3v, ¹A′₁) complexes also having the corresponding d-orbital aromatic characters.