Crystal structure and Hirshfeld-surface analysis of diaquabis(5-methyl-1H-1,2,4-triazole-3-carboxylato)copper(II)

The title compound, [Cu(HL)2(H2O)2] or [Cu(C4H4N3O2)2(H2O)2], is a mononuclear octahedral CuII complex based on 5-methyl-1H-1,2,4-triazole-3-carboxylic acid (H2L). [Cu(HL)2(H2O)2] was synthesized by reaction of H2L with copper(II) nitrate hexahydrate (2:1 stoichiometric ratio) in water under ambient conditions to produce clear light-blue crystals. The central Cu atom exhibits an N2O4 coordination environment in an elongated octahedral geometry provided by two bidentate HL− anions in the equatorial plane and two water molecules in the axial positions. Hirshfeld surface analysis revealed that the most important contributions to the surface contacts are from H...O/O...H (33.1%), H...H (29.5%) and H...N/N...H (19.3%) interactions.