Contrary to the all-nitrogen coordinated compounds, the ßketoiminates tend to form mononuclear structures crystalizing with high symmetry in the orthorhombic (compound ßIII) and tetragonal (compound ßIV) crystal systems, while only one dinuclear triclinic structure for compound ßII was found. As an unique case this cannot be found for structurally similar Mn ßdiketones or ß-diketiminates. Due to the liquid state of compound ßI at room temperature, the structure could not be determined. The structure of compounds ßII -ßIV are depicted in Figure , while the respective selected structural parameters are summarized in Table . This information is complimented by τ4 and τ5 indices as well as ligand distortion angles which turned out to be significant for dinuclear ßII. In this regard, the ligand distortion was measured as the angle between two planes constructed between the oxygen or nitrogen and the three enclosed carbon atoms of the ligand, as illustrated in Figure S 5. For the mononuclear tetrahedral compounds ßIII and ßIV (Figure and), the angle between these planes is around 0°, due to the delocalized backbone in the ligand system. Interestingly in the case of compound ßII (Figure ), it is only observed for the nonbridging ligands (6.2°). The bridging ligands were distorted by 15.6°. This can be explained by the extraordinary bonding situation of these ligands. Comparable to the non-bridging ligands, the nitrogen atoms are coordinated to one manganese atom, but the oxygen atom forms a 3 centered bond between both manganese atoms of the dinuclear structure. This extended contribution of the valence electrons of the oxygen atom has a direct influence on the electron density of the pi system in the ligand backbone and enables the necessary distortion of the bridging ligand. Consequently, the Mn-O distance within this 3center bonding is much longer with 2.159 Å compared to the nonbridging Mn-O bond length of 2.063 Å. Finally, the special multi center bonding situation results in a fivefold coordination sphere as a distorted trigonal bipyramidal coordination with a τ5 value of 0.86, which is close to an ideal trigonal bipyramidal geometry. The difference in the coordination sphere consequently results in another ligand field splitting for the trigonal bipyramidal coordination with four energetically low d-orbitals (dxy, dxz, dyz, dx 2 y 2 ) and an energetically high dz 2 -orbital. This finally confirms the findings and the corresponding postulated explanation of the magnetic moment measurements, as discussed above. In contrast, the mononuclear structures of compounds ßIII and ßIV reveal a distorted tetrahedral coordination with τ4 values of 0.82 and 0.83, respectively. This indicates the high structural similarity of both compounds, which is again seen by comparing the Mn-O bond length with 2.013 Å and 2.019 Å, respectively. Considering the Mn-N bonds, the structural impact of the substituent variation was observed. Through the higher steric impact of the substituent on the nitrogen, the Mn-N bond is slightly longer for the tert-butyl derivate (ßIV) with 2.146 Å in contrast to 2.119 Å for the iso-propyl derivate (ßIII).