reported a best estimate of ∆E S 0 -T 0 of the triphenyl copper corrole of 7.4 kcal/mol based on DFT optimized structures and RASPT2 energies. These values remain consistent with reports that the triplet state is thermally accessible by variable temperature proton NMR for corroles with various substituents. For example, a ∆E S 0 -T 0 of 3.3 kcal/mol has been estimated for a 5,15-dipentafluorophenyl-10-methylbenzoate substituted copper corrole, while ∆H S 0 -T 0 of 5.8 kcal/mol was reported for the β-octaethyl-5,15-diphenyl corrole. The energies of the bare and triphenyl corroles are also reported with the DFT functionals (Tables and). For the bare copper corrole, the values for ∆E S 0 -T 0 range from -4.6 to +9.6 kcal/mol for the DFT functionals, with PBE0-D3 and PBE-D3 marking the extremes. If one limits the tested functionals to the pure and hybrid meta generalized gradient (metaGGA) functionals, the range is only reduced to -2.3 to 5.4 kcal/mol. A similar trend is observed for the 5,10,15-triphenyl copper corrole. Most notably, the functional choice can result in a change in the assigned ground state spin. All four pure functionals and TPSSh-D3 result in a singlet ground state for both the bare and triphenyl corroles. On the other hand, the remaining hybrid functionals (B3LYP-D3, PBE0-D3, and M06) yield triplet ground states for both corroles. In some ways, this is consistent with prior reports that increasing the percent of HF exchange favors the high spin ground state. TPSSh-D3 has the lowest amount of HF exchange for the hybrid functionals (10%) and its ∆E S 0 -T 0 is very close to those obtained from XMS-CASPT2 and RASPT2. If the amount of HF exchanged is increased further, the triplet becomes the ground state and is increasingly more stable with higher HF exchange: