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) r eact with pyridines (L = pyridine, alpha -picoline and gamma -picoline) to form the corresponding ortho-palladated derivatives [Pd(az)XL]. The compoun ds 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 ou t in dynamic nitrogen atmosphere. From DSC analyses the beats of decomposit ion were calculated. The kinetics of the first step of thermal decompositio n 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.