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 [Rh-2(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 [Rh-2(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 sigma and delta orbitals changed when the Rh-OH2 length was 2.35 angstrom. The natural orbital (NO) analyses and chemical indices clearly indicate that there is a sigma-type single bond between the Rh ions, and that the axial H2Os does not affect the overlap.