Synthesis, crystal structure and Hirshfeld surface analysis of a new copper(II) complex based on diethyl 2,2′-(4H- 1,2,4-triazole-3,5-diyl)diacetate

The title compound, bis[mu-2,2 '-(4H-1,2,4-triazole-3,5-diyl)diacetato]bis[diaqua-copper(II)] dihydrate, [Cu-2(C6H5N3O4)(2)(H2O)(4)]center dot 2H(2)O, is a dinuclear octahedral Cu-II triazole-based complex. The central copper atoms are hexaco-ordinated by two nitrogen atoms in the equatorial positions, two equatorial oxygen atoms of two carboxylate substituents in position 3 and 5 of the 1,2,4-triazole ring, and two axial oxygen atoms of two water molecules. Two additional solvent water molecules are linked to the title molecule by O-H center dot center dot center dot N and O center dot center dot center dot H-O hydrogen bonds. The crystal structure is built up from the parallel packing of discrete supramolecular chains running along the a-axis direction. Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from H center dot center dot center dot O/O center dot center dot center dot H (53.5%), H center dot center dot center dot H (28.1%), O center dot center dot center dot O (6.3%) and H center dot center dot center dot C/C center dot center dot center dot H (6.2%) interactions. The crystal studied was twinned by a twofold rotation around [100].