The adsorption energy of N2O onto the M site from the gas phase is -13.2 kJ/mol, of which 102% is contributed by dispersion interactions (PBE level of theory). A single point HSE06 calculation yields an adsorption energy of -15.8 kJ/mol. As expected, the adsorption energy is only slightly influenced by the choice of functional. We therefore only report PBE energies for adsorption and desorption steps to reduce computational costs. The N-O bond splitting exhibits an energy barrier of +119.0 kJ/mol (HSE06; for PBE +70.7 kJ/mol). The corresponding NEB reaction path is shown in Figure . This energy barrier is comparable to previously reported DFT data for the creation of iron-oxo species. The energy barrier is also lower (PBE) or close to (HSE06) many calculated energy barriers for N2O at open metal sites that are known to form metal-oxo sites with N2O in experiments. The results suggest that the activation of M to MO is feasible in this system. The S=2 spin state is confirmed for the iron-oxo species MO to be lower in energy than S=1 and S=0 (both for PBE and single-point HSE06 calculations). The obtained energies relative to the S=2 state at the SP HSE06 level of theory are ΔE(S=1)=+83.1 kJ/mol and ΔE(S=0)=+114.9 kJ/mol. Therefore, all further calculations employ the S=2 quintet state. For the activation step using N2O, the S=2 spin state has also recently been found to exhibit the lowest energy barrier for the creation of an iron-oxo species in iron zeolites. Our results are furthermore in line with previous DFT studies of C-H activation on Fe=O species, even though it is known that the S=2 spin state is not necessarily the only reactive state: The spin state may change during the transition from reactants over transition state to products, leading to multi-state reactivity. Our HSE06 results are in line with these previous studies and favor the S=2 state for both M and MO. Also, the error introduced by fixing the spin state of our system for the entire catalytic cycle cannot be expected to be overcome using DFT in any flavor, as DFT in general is not able to resolve subtle energy differences of multi-state reactivity of transition metal systems. Fixing the spin state is therefore a necessary choice to achieving our goals. If the S=2 state is indeed the ground state, reactivity of the iron-oxo species in this MOF system can be expected to be high, as experimental evidence for similar systems suggests that the S=2 state is more reactive than lower spin states.