Thermally induced structural transformations of a series of palladium(II) complexes with N-heteroaromatic bidentate hydrazone ligands
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2014
Authors
Begović, NebojšaBlagojević, Vladimir A.

Ostojić, Sanja

Micić, Darko

Filipović, Nenad

Andjelković, Katarina

Minić, Dragica M.
Article (Published version)

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Thermal stability of a series of palladium(II) complexes with N-heteroaromatic bidentate hydrazone ligands was investigated using a combination of experimental measurements and DFT calculations. All complexes exhibit a reversible second-order transition around 333 K, which can be attributed to structural reorganization of the ligand molecules. Thermal degradation begins in 570-610 K temperature region, with an endothermic peak, followed by exothermic peaks in DSC. TG measurements show a well-defined mass loss corresponding to the initial degradation, while subsequent processes are poorly separated. DFT calculations suggest that the initial degradation step occurs with release of Cl, which then reacts with remaining part of the complex molecule in an exothermic process. This leads to decomposition of the ligand molecule into four fragments corresponding to ethyl chloride, carbon dioxide, methyl amine, and the fragment with the aromatic group. Mass spectrum suggests that creation of thes...e fragments most likely corresponds to the initial degradation, after which some of these coordinate to Pd center, whose coordination sphere is left incomplete by release of Cl. TG measurement to 1123 K indicates that the final degradation product at this temperature is palladium.
Keywords:
Palladium complex / Thermal degradation / DFT calculations / Reaction mechanism / Chelate ligandSource:
Thermochimica Acta, 2014, 592, 23-30Publisher:
- Elsevier, Amsterdam
Funding / projects:
- Dynamics of nonlinear physicochemical and biochemical systems with modeling and predicting of their behavior under nonequilibrium conditions (RS-172015)
- Experimental and theoretical study of reactivity and biological activity of stereodefined thiazolidines and their synthetic analogues (RS-172020)
- Interactions of natural products, their derivatives and coordination compounds with proteins and nucleic acids (RS-172055)
DOI: 10.1016/j.tca.2014.08.005
ISSN: 0040-6031