This spin state assignment of 8 was further confirmed by an X-Band CW-EPR measurement performed on a ground microcrystalline sample at 5 K (Fig. ), showing a broad highly anisotropic signal in the 500-10000 Oe magnetic field range. Simulation of the experimental spectrum resulted in the axial and rhombic ZFS parameters and g-tensor values in a reasonable agreement with the values reported for pentacoordinate Mn(II) complexes. These parameters were also corroborated by the CASSCF/NEVPT2 calculations performed on a model complex 8* -a simplified version of 8, lacking the quinoxaline walls and with the butyl tails truncated (Table ).