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

Abstract

The theoretical understanding of the magneto-structural correlations of an oximatobridged 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 (α), O N Cu bond angle (β), N O bond length (R N-O ), and Cu•••Cu distance (R 0 ), was evaluated. The data showed that J calc initially decreased and then increased as bond angles α and β increased. These relationships were expressed by unary quadratic functions. However, J calc varied linearly with the bond length, R N-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 α, β, R N-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.binuclear copper(II) complexes, DFT-BS, magneto-structural maps, oximato-bridged | INTRODUCTIONResearch on single-molecule magnets has been steadily growing since the early 1990s when the first molecule with macroscopic hysteresis loop behavior was discovered [1]. Since then, several single-molecule magnets have been designed and synthesized using bridging ligands that contain lone pairs of electrons [2][3][4][5]. The interaction between the paramagnetic metal ion orbitals and the ligand orbitals of dinuclear metal complexes containing inorganic/organic small bridging ligands can be described using theoretical models. This aids in expanding the magnetic structure relationship of the complex molecular magnets, which attracts the attention of synthetic chemists to this field [6,7]. It is worth mentioning that dinuclear metal complexes are also active centers of proteases, such as tyrosinase, and copper oxidase, that are important for some life processes [8,9].Currently, the organic ligand containing the oxime group ( C N O) is of interest because of its structural and magnetic characteristics. The oximato-bridged dinuclear metal complex has a delocalized conjugate π bond in the plane of the oxime group because the three atoms, C, N,