Thermal studies of sulphonamide derivative complexes: Part III. Thermal behaviour of acetazolamide complexes of Co(II), Ni(II) and Cu(II) with ethylamine, diethylamine, triethylamine and potassium hydroxide

Abstract

A thermal study of a new series of acetazolamidate complexes of Co(II), Ni(II) and Cu(II) using the TG, DTG and DTA techniques in flowing air, static air and N 2 atmospheres is described. From the TG-DTG and DTA curves, different thermal behaviours can be observed. Although in all the complexes the processes of dehydration, deammination and pyrolysis can be clearly observed, in some cases they appear as several well-separated steps and, in others, as continuous stages which take place simultaneously. The differences observed between the pyrolytic decomposition in flowing air and in nitrogen are described. In flowing air, metal sulphate is formed from the thiadiazole ring, except for potassium salts in which the sulphate derives from the sulphonamide group. The formation of sulphate from the thiadiazole ring is accompanied by a strong exothermic peak in the DTA curve. In contrast, in nitrogen, metal sulphide nor sulphate is formed.