For these model systems, relevant stationary points along the OM reaction path were calculated. This includes the initial olefin adduct, the corresponding metallacyclobutane structure, as well as the transition states (TS) for [2+2] cycloaddition, cycloreversion and cyclopropanation for all relevant spin states. Since all model complexes exhibit a d 6 electron configuration, a low-spin (S = 0) singlet state, a triplet state (S = 1) and a quintet high-spin (S = 2) state can be relevant. For calculations of the electronic structure and thermodynamic parameters, we adopted the meta-hybrid exchange-correlation functional TPSSh (with 10% HF exchange), as it was found to accurately predict spin state splittings of manganese and iron based spin cross-over compounds. Nevertheless, other density functionals were also used, as well as DLPNO-CCSD(T) calculations were performed on selected structures to gauge the accuracy of the methodology.