Quantum-chemical study of the structure and magnetic properties of mono- and binuclear Cu(II) complexes with 1,3-bis(3-(pyrimidin-2-yl)-1H-1,2,4-triazol-5-yl)propane

On the basis of X-ray crystallographic data on molecular copper complexes with 1,3-bis(3-(pyrimidin-2-yl)-1H-1,2,4-triazol-5-yl)propane, quantum-chemical optimization of their equilibrium structure has been performed by the density functional theory method with subsequent analysis of the electron density distribution by Bader’s atoms in molecules method and g-factor anisotropy calculation. The topological parameters of electron density at the Cu–N bond critical points have been considered, and the bond energies have been estimated using the Espinosa equation. A phenomenon of variable coordination of nitrate ions with Cu(II) ions in the inner coordination sphere of the mononuclear copper complex with 1,3-bis(3-(pyrimidin-2-yl)-1H-1,2,4-triazol-5-yl)propane has been revealed. The contributions of different components to the gfactor anisotropy have been analyzed in the framework of the gauge-independent atomic orbital method. The largest contribution to the g-factor is made by the orbital (Zeeman) and spin–orbit components accounting for very high averaged g-factor values of 2.1413 and 2.5636 for the doublet state of the mononuclear complex and the triplet state of the binuclear complex, respectively.