In the proposed mechanism, the CH3 radical reacts with an OH group to from a bound methanol molecule. We find an overall reaction energy ΔE(CH4@MO → CH3OH@M) of -173.5 kJ/mol (HSE06; for PBE -30.9kJ/mol). Including ad-and desorption energies, the overall reaction energy for CH4 + MO → CH3OH + M is -148.4 kJ/mol (HSE06; for PBE -11.1 kJ/mol). For comparison, we calculated reaction energies for syngas creation, complete oxidation, and the C-H bond strength using the same methodology. The reaction energies are given in Table . Contrary to the strong functional dependence of reaction energies discussed for the N2O bond breaking above, the functional dependence is much smaller for the simple reactions in Table , with the largest deviation between HSE06 and PBE being only 12 kJ/mol. For the MOF system, however, the difference between HSE06 and PBE is again very large, with a value of ΔΔER(PBE-HSE06) = +142.6 kJ/mol. We can therefore conclude that the difficulties of DFT in this case lie in the description of the active metal species involved and not within the small guest molecules in contrast to the reaction of N2O with M. If we take the methyl radical as the relevant transition state ( 1 TS CH ), the energy barrier (ΔEB) for H abstraction at the MO site is +55 kJ/mol (HSE06; approx. +125 kJ/mol for PBE), which is comparable to values of other well performing iron-oxo sites from our group. However, as noted above, we expected the methyl radical to be a stable intermediate, not a transition state. To complete the analysis of the C-H bond activation step, we performed two NEB calculations: one from CH4@MO to 1 TS CH and another from 1 TS CH to CH3OH@M. Surprisingly, these two NEB calculations, when combined from CH4@MO to CH3OH@M (Figure , combined from Figures and), show that there is a prominent energy plateau region around 1 TS CH . Further calculations showed that there are two transition states within 6 kJ/mol of each other with little geometric differences within the plateau region. As discussed earlier, the limitations of DFT in this system, will make a detailed exploration of subtle energy differences on this plateau of the potential energy surface difficult, but for our purposes here the exact shape of the plateau region is not needed.