Kinetics of thermolysis of some transition metal perchlorate complexes with 1,4-diaminobutane ligand

Three metal perchlorate complexes of general formula [M(dab)2](ClO4)2·xH2O (where M = Zn, Cu and Ni; dab = 1,4-diaminobutane) have been prepared and characterized by gravimetry, infrared spectroscopy (IR) and elemental analysis. Thermolysis has been studied by thermogravimetry (TG) in air and simultaneous thermogravimetry-differential thermogravimetry-differential thermal analysis (TG-DTG-DTA) and differential scanning calorimetry (DSC) in N2 atmosphere. Isothermal gravimetry over the temperature range of initial decomposition of the complexes has been done to evaluate the kinetics. Both model fitting and isoconversional methods have been used for the evaluation of the kinetics. Model fitting gives a single value of activation energy (E) whereas the isoconversional method yields a series of E values which vary with extent of conversion. Ignition with varying amounts of the complexes was measured to see the response to rapid heating. The thermal stability order of the complexes is [Zn(dab)2](ClO4)2 ≫ [Cu(dab)2](ClO4)2.2H2O ≈ [Ni(dab)2](ClO4)2.