Thermal decomposition kinetics of palladium(II) 1-allylimidazole complexes

Thermal dehydration and decomposition processes of a Pd(II) coordination compound, [PdL(4)]Cl(2)(.)3H(2)O (1), (where L is 1-allylimidazole) were studied by simultaneous TG/DSC techniques under constant heating rates condition. The released gas products were analyzed by online coupling a FTIR spectrometer to the TG equipment. The so obtained evolved gas analysis confirmed that only two ligand molecules were released and that a new 1-allylimidazole Pd(II) complex, trans-[PdL(2)Cl(2)] (2a), was obtained. The same coordination compound was also prepared by heating 1 at 413.15 K in air atmosphere until a constant weight was reached 2b. Thermal decomposition mechanisms for the 2a and 2b complexes examined were proposed according to the three mass loss steps derived by TG data. Based on the model-free isoconversional method described by Flynn-Wall-Ozawa (FWO), the dependencies of activation energy on the degree of conversion were determined. A model-free "single point" method was also applied using the Kissinger equation, and derived results were compared to those of the former method. (c) 2005 Wiley Periodicals, Inc.