Crystal structure and thermal decomposition mechanism of a 5-aminotetrazole copper(II) complex

A novel 5-aminotetrazole mixed ligands complex of formula [Cu(PTS) ₂(ATZ) ₂(H ₂O) ₂] (C ₁₆H ₂₄CuN ₁₀O ₈S ₂, PTS = p-toluenesulfonate, ATZ = 5-aminotetrazole) has been obtained by the reaction of 5-aminotetrazole with copper acetate and p-toluenesulfonic acid on heating in water. It was characterized by elemental analysis, FT-IR spectroscopy, and X-ray single crystal diffraction. The compound crystallizes in monoclinic system, space group P2 ₁/c, Z = 2, a = 14.079(4) Å , b = 6.088(3) Å , c = 14.632(4) Å , β = 105.268(4)°, V = 1209.8(5) Å ³. The central copper(II) cation is coordinated by two N atoms and four O atoms from two ATZ ligands, two water molecules and two p-toluenesulfonate ions to form a six-coordinated and distorted octahedral structure. Neutral ATZ is coordinated in the monodentate mode by the N(4) atom. The sulfonate group of the PTS ligand remains weak-coordinated modes and forms a number of hydrogen bonds with water molecule ligands and ATZ ligands. A supramolecular framework is connected by electrostatic interaction, weak coordinated bonding, hydrogen-bonding, and p-p interaction. The thermal decomposition mechanism of the title compound was predicted based on DSC, TG-DTG, and FT-IR analyses. Thermolysis of ATZ and its several derivatives is compared.