Synthesis, structural characterization, electrochemistry and spectroelectrochemistry of dinuclear copper(II) metal complexes stabilized by a tetradentate NOOO salicylaldimine ligands

Abstract

Abstract The synthesis, structure, spectroscopic and electro-spectrochemical properties of salicylaldimine Schiff-base ligands (L n H) ( n = 1, 2, and 3) (L 1 H = N -[2-amino-8-hydroxyquinoline]-salicylaldimine, L 2 H = N -[2-amino-8-hydroxyquinoline]-5-bromosalicylaldimine and L 3 H = N -[2-amino-8-hydroxyquinoline]-5-methoxysalicylaldimine), respectively, and their dinuclear copper(II) complexes [Cu 2 (L n ) 2 ] are described. Three new dissymmetric tetradentate salicylaldimine ligands containing a donor set of NOOO were prepared by reaction of 2-amino-8-hydroxyquinoline with different salicylaldehydes. The dinuclear copper(II) metal complexes of these ligands were synthesized by treating an ethanolic solution of the appropriate ligand with an equimolar amount of Cu(Ac) 2 ·H 2 O. The ligands and their copper complexes were characterized by FT-IR, UV–vis, 1 H NMR, elemental analysis, molar conductivity, mass spectra and thermal analysis methods in addition to magnetic susceptibility and spectroelectrochemical techniques. The reaction of these ligands in a 1:1 mole ratio with copper(II) acetate afforded dinuclear Cu(II) metal complexes. The room temperature magnetic moments of [Cu 2 (L n ) 2 ] complexes are found between 1.12 and 1.28 BM for per Cu(II) molecule.