For all catalysts and active sites in Figure , no more than two principal components are necessary to capture nearly all of the variance. For catalyst A, the first principal component captures how the fluoryl, methoxy, bromyl and methyl functional groups increase the oxygen bonding strength of the catalyst when the modification is para to the active site (Table ), whereas the second component captures how nearly the same set of functional groupsmethylamine, methoxy, bromyl, and methyl-deactivate oxygen binding strength when the modification is meta to the active site (Table ). For catalysts B, the effect of the substitutions is almost entirely captured by a single principal component that broadly captures the trend of electron withdrawing groups decreasing the bonding strength of oxygen species and the reverse effect of electron donating groups (Table ). Curiously, the first principal component for C-1 and C-2 captures how various functional groups increase oxygen bonding strength, but the groupschloryl, methyl, trifluoromethyl, and bromyl for C-1 and methyl, cyanyl, trifluoromethyl, and methylamine for C-2-do not follow the same pattern of electron withdrawing vs donating groups as catalyst B (Table , S6). A further distinction between C-1 and C-2 is that C-2 exhibits a stronger contribution from the second principal component due to the epoxide structure of the 𝑅 -𝑂 intermediate at the C-2 active site. PCA thus helps make sense of the complexity of these functional group effects, but additional data is necessary to understand the complexity of the observed deviations on catalyst C from the traditionally expected effects of electron withdrawing and donating groups (Table , S8).