Thermal and kinetic analysis of ortho-palladated complexes with pyridines

The complexes [Pd(az)(mu -X)](2) (az = 2(phenylazo)phenyl; X - C1, Br, I) react with pyridines (L = pyridine, alpha -picoline and gamma -picoline) to form the corresponding ortho-palladated derivatives [Pd(az)XL]. The compounds have been characterized by C, H and N analyses and spectroscopic methods (IR and H-1-NMR). TC, DTG and DSC studies of the complexes were carried out in dynamic nitrogen atmosphere. From DSC analyses the beats of decomposition were calculated. The kinetics of the first step of thermal decomposition were evaluated from TG data by isothermal and non-isothermal methods. The activation energies obtained are in the range 90-110; kJ mol(-1). The best fitting for isothermal data was observed for R-n and A(1.5) kinetic models; for non-isothermal experiments the mechanisms that best fit the data are R-n and F-1. (C) 2000 Elsevier Science B.V. All rights reserved.