Synthesis, Characterization, and Crystal Structure Determination of a New Copper(II) Complex: [H2en][Cu(pydc)2].2H2O

The new complex of [H2en][Cu(pydc)2].2H2O (1) (where H2en and pydc are ethylenediammonium and 2,6-pyridinedicarboxylate, respectively) was synthesized by the reaction of a mixture of ethylenediamine (en) and 2,6-pyridinedicarboxylic acid (H2pydc) in a mixture of CH3OH/H2O as solvent. This complex was fully characterized by elemental analysis, IR, UV–Vis spectroscopy as well as single-crystal X-ray diffraction method. The crystallographic analysis revealed that the complex of 1 consists of discrete [Cu(pydc)2]2- anion, two bis(protonated) ethylenediamine cation and two crystal water molecules. In the anionic part of this complex, the copper(II) cation is coordinated by two tridentate pydc anionic ligands through the two oxygen atoms of two carboxylate groups and one nitrogen atom of pyridine ring. Also, in this complex, intermolecular C-H…O, N-H…O and O-H…O hydrogen bonds and the strong π…π interactions between the pyridine rings are effective on the stabilization of the crystal packing.