The dependence of spin state energetics and Mössbauer parameters on the size of the molecular model is shown in Figure for A 2+ and B. Strikingly, no true high spin (HS 1) or low spin (LS 1) state appears within 10 kcal mol -1 for any of the model sizes. This is an important observation since high spin Fe(II) is observed as a key signature in FeNC catalysts and has often been attributed to models of this type. Intermediate spin states, that are expected from a ligand field perspective, as well as ring-open-shell high spin (HS 3) and intramolecular redox high spin states (HS 2) are predicted to be low-lying, possibly even as a ground state configuration.