Theoretical Study on the Electronic Configurations and Nature of Chemical Bonds of Dirhodium Tetraacetato Complexes [Rh2(CH3COO)4(L)2] (L = H2O, Free): Broken Symmetry Approach

The electronic configurations and the nature of chemical bonds of the classical lantern-type dinuclear rhodium(II) tetraacetato complexes [Rh2(CH3COO)4(L)2] (L = H2O, free) have been carefully investigated with broken symmetry (BS) Hartree–Fock (HF), BS density functional theory (DFT), and BS hybrid DFT (HDFT) methods. Several electronic configurations have been proposed for the ground states of the [Rh2(RCOO)4(H2O)2] complexes. In this study, we concluded that those different electronic configurations originate from the position of the axial H2Os, and not along the Rh–Rh length. The BS(U)B3LYP calculation indicates that the stability of the σ and δ orbitals changed when the Rh–OH2 length was 2.35 Å. The natural orbital (NO) analyses and chemical indices clearly indicate that there is a σ-type single bond between the Rh ions, and that the axial H2Os does not affect the overlap.