Construction and thermal decomposition properties of Nickel (Ⅱ) complex with 1-(4-benzoic acid)- 3-(pyrazinyl)-1H-1,2,4-triazole ligand

In order to investigate the thermal stability of nickel(Ⅱ)-based complexes, the semirigid ligand 1-(4-benzoic acid)-3-(pyrazinyl)-1H-1,2,4-triazole (HL), which contains triazole, pyrazinyl and carboxylic acid groups at the same time, was chosen to grow crystals by reacting with nickel(Ⅱ), a transition metal, in a mixed-solvent environment of acetonitrile, nitric acid and water. The carboxylic acid group in the ligand (HL) promotes a more diversified structure of the complex through the metal-carboxylic structural unit formed with the metal ions, while the nitrogen-containing group is to form a strong coordination bond with the transition metal ions to improve the stability of the complex. A novel nickel(Ⅱ)-based complex named 1 was successfully constructed by the conventional solvothermal method, and the complex 1 was characterized by single-crystal structure analysis, powder XRD experiments, FTIR detection, and thermal decomposition properties by thermogravimetric experiments. Single-crystal structure analysis shows that the complex 1 belongs to the monoclinic crystal system, C2/c space group, with cell parameters of a=11.897(3) Å, b=10.207(3) Å, c=30.556(7) Å, α=γ=90°, β=95.064(8)°, and V=3 696.0(17) Å3, and the coordination configuration of the complex 1 is a six-coordinated octahedron. Thermogravimetric experiments show that the framework structure of complex 1 is thermally stable compared to HL ligand and other nitrogen-containing carboxylic acid complexes.