Exchange interaction of Mo with 3d and 4d metals in complexes with dithiooxamide: a theoretical modeling

Quantum chemical calculations of the molecular and electronic structure of the complexes [(L)2M13+(L)M22+(L)2]5− (M13+ is the Mo ion in the oxidation state +3; M22+ is the 3d and 4d transition-metal (Fe, Ru, Rh, Pd) ion in the oxidation state +2; and L is the dithiooxamide ligand) were carried out to search for pairs of metals corresponding to the maximum value of the exchange coupling constant J. Molecular structure calculations of the complexes were performed in the B3LYP/LANL2DZ approximation while the J constants were obtained from B3LYP/TZV calculations. It was shown that replacement of 3d transition-metal ions in the oxidation state +2 by 4d transition-metal ions in the oxidation state +2 leads to higher J values. It was established that the J values change in parallel with the difference between the total spin density on the M13+ and M22+ metal ions in the complexes and in the isolated M13+ and M22+ ions. © 2022, Springer Science+Business Media LLC.