Job submission was automated by molSimplify 107,108 with a 24 h wall-time limit per run with up to five resubmissions. Geometry optimizations were carried out with geometry checks 109 prior to each resubmission and structures that failed any checks were eliminated. Open-shell structures were also eliminated from the data set following established checks, if the expectation value of the Ŝ 2 operator deviated from its expected value of S(S + 1) by > 1 or the combined Mulliken spin density on the metal and the oxygen in the active site moiety differed from the total spin by > 1 µB (Supporting Information Text S2 and Table ).