Electronic and magnetic properties of the binuclear [Mn2{(OPPh2)2N}4] complex, as revealed by magnetometry, EPR and density functional broken-symmetry studies

In this work, magnetometry and EPR spectroscopy studies on the binuclear Mn(II) complex [Mn2{(OPPh2)2N}4] (1) established antiferromagnetic interactions between the two S = 5/2 Mn(II) centers being at 3.378 Å from each other. The magnitude of the JAB coupling constant, in the framework of the HˆHDvV=-2JABSˆASˆB formalism, was determined to be −4.5 ± 0.5 cm−1, by the temperature dependence of the magnetic susceptibility of 1. This value is comparable with the one of the previously studied [Mn2{(OPPh2)[OP(OEt)2]N}4(H2O)2] complex (−3.5 cm−1), which bears similar type of ligands. The antiferromagnetic nature of the coupling within the binuclear Mn2O4 core of 1 was unequivocally confirmed also by EPR studies on frozen CH2Cl2 solutions at various temperatures. Density functional broken-symmetry calculations confirmed the above experimental findings and provided JAB values in close agreement with the experiment. Comparisons with literature binuclear Co(II) or Mn(II) complexes were made.

Graphical abstractThe binuclear [Mn2{(OPPh2)2N}4] complex was studied by magnetometry and EPR spectroscopy, which established antiferromagnetic interactions between the two S = 5/2 Mn(II) centers, both in the solid state and in solution. Density functional broken-symmetry calculations confirmed the above experimental findings and provided JAB values in close agreement with the experiment.Figure optionsDownload full-size imageDownload as PowerPoint slide