Antiferromagnetic resorcinol bridged dinuclear square-planar copper (II) complexes: Syntheses, structural, spectroscopic and magnetic properties

A new C₂-symmetric Schiff base ligand (H₂L) featuring a core resorcinol bridging unit has been created, utilizing the Duff formylation reaction followed by the Schiff base condensation reaction. The ligand was characterized by various spectroscopic techniques. Cu(II) salts with varying coordinating anions (Cl⁻ and SCN⁻) in methanol were allowed to react with this ligand in a 2:1 M ratio to create dinuclear Cu(II) complexes. The complexes were isolated in pure form and characterized by, elemental analysis,single crystal X-ray crystallography and various spectroscopic techniques. X-ray analysis discloses that both complexes are dinuclear, where the ligand (H₂L) being tridentate in nature, coordinates to Cu(II) through its two N donor atoms and one O donor atom in the equatorial positions. The respective anions (−Cl⁻ for 1 and –SCN⁻ for 2) coordinate to Cu(II) to complete its square planar geometry. Temperature dependent magnetic susceptibility measurements indicate weak antiferromagnetic exchange interactions with a coupling constant of J = −5.9(1) cm⁻¹ and g = 2.148(1) for 1 and J = −10.08(1) cm⁻¹ and g = 2.106(1) for 2.