Synthesis, characterization, and thermal behavior of palladium(II) complexes containing 4-iodopyrazole

Abstract

The mononuclear pyrazolyl complexes [PdCl2(HIPz)(2)] (1), [PdBr2(HIPz)(2)] (2), [PdI2(HIPz)(2)] (3), [Pd(SCN)(2)(HIPz)(2)] (4), and [Pd(NHCOIPz)(2)] (5) have been prepared. Compound 1 was obtained from the displacement of acetonitrile from [PdCl2(CH3CN)(2)] precursor by the 4-iodopyrazole (HIPz) ligand, whereas 2-5 were synthesized by substitution of the chlorido in 1 by the respective anionic group. The compounds were characterized by elemental analysis, infrared spectroscopy, and H-1 NMR spectroscopy. The thermal behavior of 1-5 has been studied by TG and DTA. The thermal stability of [PdX2(HIPz)(2)] compounds varies according to the trends X = Cl- < I- a parts per thousand... SCN-< Br-. No stable intermediates were isolated during the thermal decompositions due to the overlap of the degradation processes. The final products of the thermal decompositions were characterized as metallic palladium by X-ray powder diffraction.