Theoretical studies on dicopper(II) complexes of phenoxido-bridged ligands: Magneto-structural correlations

Abstract

In this work, the magnetic properties of the phenoxido-bridged binuclear copper complex [Cu2(LMe,Me,Me)2] were studied using the density functional theory-broken symmetry method by employing various functionals and basis sets, and the magneto-structural correlation was established. Encouraging results were obtained using the wB97X/def2-TZVPP level of theory, as the calculated magnetic coupling constant (−198.03 cm−1) was close to the experimental value (−197.55 cm−1). Molecular magnetic orbital and spin density analyses proved that the molecular magnetic orbital is composed of Cu(1)/Cu(2) 3dz2 orbitals and phenoxido-bridged ligand-conjugated π-type molecular orbitals, and the paramagnetic centers are dominated by spin delocalization. The magneto-structural correlation proved that the magnetic coupling constant of the complex initially increases and subsequently decreases with increase inthe CuOCu bond angle (θ). As the bond angle (θ) increases, the character of the exchange is altered from ferromagnetic to antiferromagnetic.