Journal of the American Chemical Society, Vol.138, No.6, 1922-1931, 2016
Spectroscopic Evidence for a 3d(10) Ground State Electronic Configuration and Ligand Field Inversion in [Cu(CF3)(4)](1-)
The contested electronic structure of [Cu-(CF3)(4)](1-) is investigated with UV/visible/near IR spectroscopy, Cu K-edge X-ray absorption spectroscopy, and 1s2p resonant inelastic X-ray scattering. These data, supported by density functional theory, multiplet theory, and multireference calculations, support a ground state electronic configuration in which the lowest unoccupied orbital is of predominantly trifluoromethyl character. The consensus 3d(10) configuration features an inverted ligand field in which all five metal-localized molecular orbitals are located at lower energy relative to the trifluoromethyl-centered sigma orbitals.