Preparation, crystal structure and thermal decomposition mechanisms of [Ni(NH₂NHCO₂CH₃)₃](NO ₃)₂·H₂O

The title compound [Ni(MCZ)₃](NO₃)₂ · H₂O was prepared by reaction of the aqueous solutions of nickel nitrate and methylcarbazate (MCZ). The crystal structure Of [Ni(MCZ) ₃](NO₃)₂ · H₂O was determined by using single crystal diffraction techniques and crystalline was in monoclinic system with space group P2₁/n. The unit cell parameters are as follows: a = 1.3681(2) nm, b =0.8188(1) nm, c = 1.6029(4) nm, β = 92.16(2)°, V = 1.7943(6) nm³, Z = 4, F(000) = 976, D_c = 1.744 g·cm^-3, μ(Mo Kα) = 1.166 mm^-1. Positional and thermal parameters were refined by the full-matrix least-squares method. All the non-hydrogen atoms were refined anisotropically but the hydrogen atoms were refined isotropically with the final factor values of R₁ = 0.0337 and wR₂ = 0.0857. In the title compound, methylcarbazate serves as a bidentate ligand coordinating to the nickel cation with oxygen atom from carbonyl and the nitrogen atom from hydrazine group so that a five-membered chelating ring is formed. There are three rings in the molecular structure. The coordination number is six and the configuration is octahedral. In the environment of the molecule there are two NO₃^- and one crystal water molecule, which are linked with the inside by electrostatic force and hydrogen bonds. Thermal decomposition mechanisms of the compound were characterized by using TG-DTG, DSC and IR techniques. It was confirmed that decomposing processes of the compound include one endothermal and three continuous exothermic stages, residue is NiO at 325 °C, finally.