Accurate Ionization Energies for Mononuclear Copper Complexes Remain a Challenge for Density Functional Theory.

摘要: Copper is ubiquitous and its one-electron redox chemistry central to many catalytic processes. Modeling such requires electronic structure methods capable of the accurate prediction ionization energies (IEs) for compounds including copper in different oxidation states supported by various ligands. Herein, we estimate IEs 12 mononuclear Cu species previously reported literature using 21 modern density functionals DLPNO-CCSD(T) wave function theory model; consider extrapolated values latter provide reference acceptable accuracy. Our results reveal a considerable diversity functional performance. Although there nearly always at least one that performs well any given species, are none do so every member test set, certain cases particularly pathological. Over entire SOGGA11-X best with mean unsigned error (MUE) 0.22 eV. PBE0, ωB97X-D, CAM-B3LYP, M11-L, B3LYP, M11 exhibit MUEs ranging between 0.23 0.34 eV. When relativistic effects zero-order regular approximation, PBE0 found