The cell parameters of the MOF system (170 atoms) were optimized for Fe1-MFU-4l(OH) (M) with one N2O guest molecule (M+N2O) and kept fixed for all following calculations (see below for details). The singlet, triplet, and quintet spin state energies of M and (Fe=O)1-MFU-4l(OH) (MO) were compared at the PBE optimized geometries using single point HSE06 calculations. The highspin (HS) quintet state is lowest in energy for both structures and was therefore used throughout this study.