A Dimeric Copper(II) Complex of Oxalate and Oxamide Dioxime Ligands: Synthesis, Crystal Structure, Thermal Stability, and Magnetic Properties
Résumé
The dimeric copper(II) complex [Cu(C2O4)(H2oxado)(H2O)]2 (1), where H2oxado = oxamide dioxime, has been synthesized in water and characterized by elemental and thermal analyses, IR spectroscopy, and single-crystal X-ray diffraction. Complex 1 is composed of two neutral [Cu(C2O4)(H2oxado)(H2O)] entities connected by Cu–O bonds between oxalate oxygen atoms and copper(II) ions, thereby producing a centrosymmetric dimer, with the Cu(II) centers exhibiting a strongly distorted octahedral coordination. Neighboring dimers are hydrogen-bonded through O–H⋯O interactions leading overall to a layer structure. Thermal analyses of complex 1 showed two significant weight losses corresponding to the coordinated water molecules, followed by the decomposition of the network. Variable-temperature (10–300K) magnetic susceptibility measurements revealed very weak antiferromagnetic interactions (θ =−0.86 K from Curie–Weiss law behavior) within the dinuclear unit.