Examining the release energies (DE(release)), we find that both Fe and Ru catalysts exhibit high DE(release) values (i.e., > 20 kcal/mol for all spin states, with the exception of some Fe outliers in the IS and HS states), suggesting that isopropanol release could become rate-limiting regardless of metal identity (Figure and Supporting Information Figures and). These DE(release) values are higher in this work compared to prior work because we selected catalysts from prior work with release energies that had not yet been optimized with evolutionary algorithms. Nevertheless, in the LS state, the Fe and Ru DE(release) values are quite comparable (52 kcal/mol and 50 kcal/mol on average, respectively, Figure and Supporting Information Figures and). In the IS and HS states, we generally find that DE(release) is more favorable in Ru catalysts over Fe catalysts by ca. 10 kcal/mol for both IS and HS states on average after removal of Fe outliers with DE(release) < 20 kcal/mol. We note that the Fe outliers in the higherspin states are exclusively catalysts with monodentate ligands that predominantly contain nitrogencoordinating ligands (Supporting Information Figures and). The comparatively favorable DE(release) values of these outliers primarily arise from substantial destabilization of the isopropanol-bound intermediates coupled with either stabilization or only slight destabilization of the resting state in the higher-spin states, as judged from the spin splitting energies (see Sec. 4b).