Magneto-structural correlations of oximato-bridged dinuclear copper(II) complex: A theoretical perspective

The theoretical understanding of the magneto-structural correlations of an oximato-bridged dinuclear copper(II) complex can help develop new applied molecular magnets. This study evaluated the magnetic coupling constant of a [Cu-2(hfac)(2)(ppko)(2)] complex using the density functional theory combined with the broken symmetry approach (DFT-BS). The magnetic structure correlation between the magnetic coupling constant (J(calc)) of the complex and the structural parameters, N-O-Cu bond angle (alpha), O-N-Cu bond angle (beta), N-O bond length (RN-O), and Cu center dot center dot center dot Cu distance (R-0), was evaluated. The data showed that J(calc) initially decreased and then increased as bond angles alpha and beta increased. These relationships were expressed by unary quadratic functions. However, J(calc) varied linearly with the bond length, RN-O, and spacing, R-0. Moreover, in the ground state, the magnetic coupling constant increased with a decrease in the spin density of Cu(1), but gradually decreased as the spin density of Cu(2) increased. An increase of parameters alpha, beta, RN-O, and R-0, resulted in a gradual increase in the distance between Cu(II) ions, and the square of the overlap integral between the non-orthogonal magnetic orbitals of Cu(II) ions to gradually decay. Finally, the contribution of the antiferromagnetic part decreased as the magnetic coupling constant gradually increased.