From the distributions of DEI-L values for the Fe catalysts, and considering that a majority of these catalysts favor the IS state in their resting state, we expect that Fe catalysts predominantly follow a spin-allowed pathway for C-H hydroxylation. Here, the IS resting state species is oxidized to form an IS Fe-oxo species that performs C-H activation in propane via an a-radical transfer to form an IS Fe-hydroxo species with an antiferromagnetically coupled •CH(CH3)2 radical, maintaining the overall triplet spin state following HAT. Thereafter, the isopropyl radical rebounds to form an IS isopropanol-bound intermediate and the IS resting state is recovered following isopropanol release. Nevertheless, for a small subset of catalysts for which we can converge all three spin (i.e., HS, IS, and LS) states, we find a greater degree of variability in preferred spin state of Fe catalysts than the equivalent Ru catalysts (Supporting Information Figure and Text S3). While these conclusions may be expected to be somewhat sensitive to the functional chosen, 118 qualitative trends are likely preserved. Depending on ligand chemistry, spinallowed pathways may be destabilized in favor of spin-forbidden pathways in Fe. In particular, strong-field ligands stabilize a LS resting state, Fe-hydroxo, and isopropanol-bound intermediates but not the Fe-oxo, which always remains in an IS ground state, whereas weak-field ligands all favor a spin-allowed IS catalytic cycle.