All gas-phase geometry optimizations and single-point energy calculations were performed using density functional theory (DFT) with a development version of TeraChem v1.9. The B3LYP global hybrid functional with the empirical D3 dispersion correction 100 using Becke-Johnson damping 101 was employed for all calculations. The LACVP* composite basis set was used, which consists of a LANL2DZ effective core potential 102,103 for Fe and Ru and the 6-31G* basis set 104 for all other atoms. Basis set sensitivity tests show that basis set superposition error is not a substantial factor contributing to trends in reaction energies (Supporting Information Figure ). As in prior work, we focus on relative energetics over a large data set, and thus we neglect solvent corrections and zero-point vibrational energy or entropic corrections to avoid a prohibitive increase in computational cost.