Insights into the control of magnetic coupling in the Mn4III complex: from ferromagnetic to antiferromagnetic

Abstract

Magnetic coupling interactions of a Mn(III)(4) system are investigated by calculations based on density functional theory combined with a broken-symmetry approach (DFT-BS). Three different interactions including ferromagnetic and antiferromagnetic coupling are concomitant in this complex. This magnetic phenomenon of the complex is due to the different bridging angles between the Mn(III) centers in the three different models and the orbital complementarity of the μ-pzbg and μ-OCH(3) bridging ligands, which is proven by the analyses of the molecular orbitals. According to the analyses of the magneto-structural correlation, it is revealed that the magnetic coupling interaction switches from ferromagnetic to antiferromagnetic at the point of the bridging angle Mn-(μ-OCH(3))-Mn = 99°, which is equal to the value in the origin crystal. Significant correlation between the magnetic properties and the component of the d orbitals in these systems shows that the larger contribution of the d(z(2)) orbital corresponds to the larger ferromagnetic coupling interaction. These results should provide a means to control the magnetic coupling of the polynuclear Mn systems, which is instructive for the design of new molecular magnetic materials.

Manganese, technetium and rhenium

“…25 Computational analysis has also been used to investigate magnetic coupling in a Mn III 4 complex to aid in the design of new molecular magnets. 26 Three novel manganese(III) complexes have been synthesised, all of which contain tetrametallic cages arranged in a cube-like topology. 27 The complexes exhibit only ferromagnetic interactions between metal ions and have high-spin ground states of S = 8.…”

Theoretical Study on Magnetic Interaction in Pyrazole-Bridged Dinuclear Metal Complex: Possibility of Intramolecular Ferromagnetic Interaction by Orbital Counter-Complementarity

“…They explained this phenomenon by an orbital complementarity/counter-complementarity that originates in the orbital interaction between Cu(II) and bridging-ligands. On the other hand, the theoretical studies with ab initio and density functional theory (DFT) calculations have been one of the powerful tools for the investigation of the effective exchange integrals (J), especially for the polynuclear metal complexes [13][14][15][16][17][18][19]. Up to now, there have been only several papers that examine the exchange interactions of those complexes by theoretical calculations [14][15][16][17][18]; furthermore, those are devoted to elucidating the mechanism of the ferromagnetic interaction between two metal ions.…”