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 Re3F 3 2+/0/4− clusters are investigated using density functional theory (DFT) calculations. Out research results show that the ground state for the Re3F 3 2+/0/4− clusters is found to be triplet state 3A′1 with the D3h symmetry, quintet state 5A′ with the C s symmetry, and quintet state 5A′1 with the D3h symmetry, respectively. A detailed molecular orbital (MO) analysis reveals that the Re3F2+3 (D3h, 3A′1) dication possesses multiple (πF and partial δRe) aromaticity that is respectively responsible for the triangular F3 framework and the triangular Re3 framework in the Re3F2+3 (D3h, 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 (D3h, 5A′1) anion possesses multiple (σ and partial δ) aromaticity that is responsible for the triangular Re3 framework in the Re3F4−3 (D3h, 5A′1) cluster. We also examined their hexagonal pyramidal-type Re3F3X+ (C3v, 1A′1) (X = Li, Na, K) and Re3F3Y2+ (C3v, 1A′1) (Y = Be, Mg, Ca) complexes containing the Re3F3 (D3h, 1A′1) ligand to reveal that the Re3F3 (C3h, 1A′1) structural unit is perfectly preserved in these Re3F3X+ (C3v, 1A′1) and Re3F3Y2+ (C3v, 1A′1) complexes also having the corresponding d-orbital aromatic characters.