Protocols for Understanding the Redox Behavior of Copper-Containing Systems.

Suitability of single-reference density functional theory (DFT) methods for the calculation of redox potentials of copper-containing macrocycle complexes was confirmed by the use of T 1 diagnostics along with a verification of negligible spin contamination or wave function instability. When examining the effect of improvement in the cc-pV n Z basis set series on calculated redox potentials, the results readily converged at the cc-pVTZ level. The all-electron Def2-TZVPP basis set is shown to be a suitable choice of a basis set for the calculation of redox potentials when utilizing a cc-pVTZ geometry. The best-performing model chemistries are determined to be the M06/polarizable continuum model (PCM); therefore, a scheme for redox potential calculations of copper macrocycles using either M06/cc-pVTZ with PCM solvation is proposed to reliably reproduce experimental trends.