The Dilemma of Cr^IIINi^II Exchange Interactions: Ferromagnetism versus Antiferromagnetism

Abstract

The sign of the exchange interaction in dinuclear Cr(III)Ni(II) complexes was analyzed using theoretical methods based on density functional theory. This approach allowed us to reproduce the experimental J values correctly. In addition, the Kahn-Briat model, which uses the square of the sum of the overlaps between the magnetic orbitals to correlate with the exchange coupling constant, provided a reasonable correlation between the different types of Cr(III)Ni(II) complexes when using biorthogonalized orbitals. We also examined the exchange interactions in two polynuclear Cr(III)Ni(II) complexes: a Cr(7)Ni ring and an S-shaped Cr(12)Ni(3) complex. We concluded that both systems exhibit antiferromagentic interactions, and that the Cr(III)···Ni(II) interactions are similar in value to the C(III)···Cr(III) exchange couplings.

Jaguar: A high‐performance quantum chemistry software program with strengths in life and materials sciences

“…Such sampling can be important when developing new functionals, particularly to insure that the reported energy corresponds to the lowest energy state found by the functional. This configuration search has also been used in the developments of the DBLOC correction for the B3LYP functional, and is particularly important for bare metal atoms as well as for unsaturated metallic complexes …”

“…One active area of research in inorganic chemistry is the field of molecular magnetism because of the potential applications in the development of nanoscopic storage information units. Indeed, such metallic complexes are not only used to store information in “classical” computing devices (classical bits of computers), but can also be used in quantum computing devices via the so‐called qbit storage . The complexes involved generally include several metal atoms per complex, and the molecular magnetic properties of those entities can be characterized by the exchange interactions between the metals and the exchange coupling constant J .…”

“…To compute J, it is therefore very important to be able to tune not only the multiplicity on the different metal centers but also the relative orientation of their net spin (i.e., ferromagnetic or antiferromagnetic coupling). Such a fine tuning is possible in the initial guess algorithm employed in Jaguar, and it is therefore often used in such cases …”

Models to predict the magnetic properties of single- and multiple-bridged phosphate CuII systems: a theoretical DFT insight

“…The derived magnetic orbitals are then compared to the ones of Kahn-Briat in systems with more than one unpaired electron per metal centre. 50…”