Synthesis, Characterization and Magnetic Studies of Phthalato-Bridged Oxovanadium(IV) Binuclear Complexes

Abstract

Abstract Four new μ-phthalato binuclear oxovanadium(IV) complexes have been synthesized and characterized, namely [(VO)2(PHTH)(L)2]SO4 (L denotes 2, 2′-bipyridine (bpy), 4, 4′-dimethyl-2, 2′-bipyridine (Me2bpy), diaminoethane (en) and 1, 3-diaminopropane (pn)), where PHTH is the phthalate dianion. The temperature dependence of the magnetic susceptibility of the complexes [(VO)2(PHTH)(bpy)2]SO4 (1) and [(VO)2(PHTH)(Me2bpy)2]SO4 (2) was measured in the 4-300 K range and the observed data were successfully simulated by an equation based on the spin Hamiltonian operator H = -2JS1.S2, giving the exchange integrals J = - 6.3 cm−1 for (1) and J = - 2.8 cm−1 for (2). This indicates an antiferromagnetic spin-exchange interaction between the metal ions within each molecule. The influence of the methyl substituents in the terminal ligands on the magnetic interactions between the metals in this kind of complexes is also discussed.