Computational studies of the magneto-structural correlations in a manganese dimer with Jahn-Teller distortions

Inspired by the crystal structure of a Mn-III dinuclear complex we obtained featuring both Jahn-Teller (JT) elongation and compression distortions, we have modelled a series of complex cations based on the disordered crystal formulation; [Mn-2(L1)(2)(mu(2)-OH)(2))(4+) (1), [Mn-2(L1)(L2)(mu(2)-OH)(2))(4+) (2), [Mn-2(L2)(L1)(mu(2)-OH)(2))(4+) (3), and [Mn-2(L2)(2)(mu(2)-OH)(2))(4+) (4) (where L1 = (1E,1'E)-5-tert-butyl-3-(((4-(((5-tert-butyl-2-hydroxy-3-((E)-(hydroxyimino)methyl)benzyl)(methyl)amino)methyl)benzyl)(methyl)amino)methyl)-2-hydroxybenzaldehyde and L2 = 3,3'-(1,4-phenylenebis(methylene))bis(methylazanediyl)bis(methylene)bis(5-tert-butyl-2-hydroxybenzaldehyde)) with different geometries to investigate the effects of the distortions on the magnetic coupling parameter. All computationally modelled dimers had a ferromagnetic interaction between the Mn-III centres, with greater magnetic coupling calculated for complexes with both JT elongation and compression present. The ferromagnetic contribution to the J coupling was ascribed to the orthogonality of the singly occupied magnetic orbitals along with the cross-interaction between the unfilled Mn1(d(x2-y2)) and singly occupied Mn2(d(x2-y2)) orbitals. Constrained calculations showed that reducing the extent of the compression at Mn2 results in a concomitant increase in the dihedral angle between the JT axes, thereby reducing the relative magnitude of the magnetic coupling between Mn-III centres.

Automated summary

The researchers investigated the effects of Jahn-Teller elongation and compression distortions on magnetic coupling parameters by modeling a series of complex cations. They found that complexes with both elongation and compression demonstrated greater ferromagnetic interaction, attributed to the orthogonality of the magnetic orbitals and cross-interaction between certain orbitals.Constraints calculations also showed how reducing compression resulted in a decrease in magnetic coupling between Mn-III centers.