For the initial multireference screening, def2-SVP was used with the NormalPNO thresholds. For the benchmark energies, the def2-TZVPP and def2-QZVPP basis sets were used with TightPNO thresholds, and these results were extrapolated to the complete basis set (CBS) limit using the standard two point extrapolation schemes with individual extrapolations of the SCF 108 and correlation energies: 109