Thermal Decomposition Procedures and Thermodynamic Properties of Some Transition Metal Complexes with 2-(2-Hydroxyphenyl)Benzothiazolate

Abstract

Five complexes of M(BTZ)2 [M = Mn, Co, Ni, Cu, Zn; BTZ = 2-(2-hydroxyphenyl)benzothiazolate] were synthesized by the reaction of hydrated metal chloride with the ligand BTZ in the mixed solvent of ethanol and methanol and characterized by chemical and elemental analysis, IR spectroscopy, and thermogravimetric/differential thermogravimetric analysis (TG-DTG). The results show that their thermal decomposition temperature was over 573 K and the complexes were completely converted to oxides at higher temperature. In addition, the constant-volume combustion energies of the complexes, ΔcU, were determined by a precise rotating-bomb calorimeter (RBC-type II). Their standard molar enthalpies of combustion, ΔcHmθ, and standard molar enthalpies of formation, ΔfHmθ, were calculated at 298.15 K. The values of standard molar enthalpies of formation were derived and range between [−(339.97 ± 6.09) and −(2165.92 ± 5.91)] kJ·mol−1 for the complexes.