Preparation, molecular structure and thermal decomposition mechanisms of [Co(mcz)₃](NO₃)₂·H₂O

The new synthesized compound [Co(mcz)₃](NO₃) ₂·H₂O has been prepared by using the aqueous of cobalt nitrate and methylcarbazate(mcz) as reagents, and its crystal structure was determined by single-crystal diffraction analysis with the following data: monoclinic, space group P2₁/n, a = 13.648(3), b = 8.234(1), c = 16.144(4) Å, β = 91.96(2)°, M_r = 471.23, V = 1813.1(5) ų, Z = 4, D_c = 1.726 g/cm³, μ(MoKα) = 1.030 mm^-1, F(000) = 972, R = 0.0359 and wR = 0.0935. Methylcabazate serves as a bidentate ligand coordinating to the cobalt cation with its carbonyl oxygen atom and the first nitrogen atom, and thus a five-membered chelating ring is formed. There exist three such rings in the molecule with the coordination number of six and configuration of octahedron. Thermal decomposition mechanisms of the compound were studied by using TG-DTG, DSC and IR techniques. They confirmed that the decomposition process includes two endothermic proceeds and three exothermic proceeds, and the final residue at 300°C is CoO.