Synthesis, electrochemical and magnetic properties of new acyclic ‘side-off’ binuclear copper(II) complexes

Abstract

Binuclear copper(II) complexes [Cu₂L][ClO₄]₂ of acyclic ‘side-off’ ligands H₂L capable of providing two distinct co-ordination geometries to the metal centres have been synthesised. Cyclic voltammetric investigation of these complexes revealed that the reduction process involves two successive irreversible one-electron transfer steps at different potentials. Complexes [Cu₂LX₂](X = Cl or Br) containing halide as the counter ion were reduced relatively at more positive potentials than the corresponding perchlorate complexes. Cryomagnetic investigations reveal a weak antiferromagnetic spin exchange between the copper(II) ions within the complexes (J=–35 to –75 cm^–1). The redox and magnetic exchange properties of the complexes are found to be sensitive toward the structural variations of the ligand systems.