TGA and DTA studies on en and tmn complexes of Cu(II) chloride, nitrate, sulphate, acetate and oxalate

Dynamic thermogravimetric and differential thermal analysis (TGA and DTA) of ethylenediamine (en) and tetramethylethylenediamine (tmn) complexes of a number of Cu(II) salts (chloride, nitrate, sulphate, acetate and oxalate) have been carried out. The thermal decomposition of these complexes occurs in steps involving dehydration, deamination and deanionation processes. However, majority of the weight loss steps in TGA are found to be composite in nature involving simultaneous loss of the component moieties in varying proportions. The DeltaH and E-a values for various steps are deduced and the observed trends are analysed in terms of the nature of the processes underlying the steps and the differences in the nature of co-ordination of the ligands and/or the stereochemistry exhibited by the counter anions about the Cu(II) ion in the complex. (C) 2002 Elsevier Science B.V. All rights reserved.