Synthesis, crystal structure, electrochemical and magnetic properties of dinuclear complexes with strong electron-drawing groups in the diphenoxo-tetraaza macrocyclic ligand

Abstract

Three symmetrical macrocyclic dinuclear complexes [M2L(H2O) n ](ClO4)2 (M2+ = Cu2+, Ni2+, Mn2+ and n = 0, 2) have been synthesized by cyclocondensation between 2,6-diformyl-4-fluorophenol and 1,4-diaminobutane in the presence of M2+ cations. The crystal structure of [Cu2L](ClO4)2 was determined by X-ray diffraction techniques. The electronic and magnetic properties of the complexes were studied by cyclic voltammetry and magnetic susceptibility. The results confirm that the complexes obtain electrons easily and there are very strong antiferromagnetic couplings between two copper(II) ions in [Cu2L](ClO4)2. The strong electron-drawing groups of fluorine attached to the phenyl ring of a macrocyclic complex enhances the antiferromagnetic exchange of the complex and makes it more easily reduced than its analogs.