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- Author or Editor: D. Petrović x
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Abstract
The thermal decomposition of copper(II) complexes with salicylaldehyde S-methylthiosemicarbazone of general formula Cu(HL)X·nH2O (X=Py+NO3, NCS, 0.5SO4) and [Cu(L)NH3]·H2O was investigated in air atmosphere in the interval from room temperature to 1000°C. Decomposition of the complexes occurred in several successive endothermic and exothermic processes, and the residue was in all cases CuO.
Abstract
The paper describes the results of differential thermal analysis of the octahedral Fe(III) complexes of the general formula [Fe(HLn)2]Cl and Fe(HL3)L3, as well as of the corresponding ligands H2Ln (H2Ln — tridentate salicylaldehyde semi thiosemi- and S-methylisothiosemi-carabazones with n=1, 2 and 3 respectively). The decomposition of the complexes involving sulphur-containing ligands (H2L2 and H2L3) starts with sulphur elimination. In case of the complexes [Fe(HL2)]Cl and [Fe(HL3)]Cl sulphur evolves independently, whereas with Fe(HL3)L3 it is eliminated within the SCH3 group. In the former case, sulphur elimination takes place at the same temperature for both complexes. The change in the coordination mode, being a consequence of the replacement of O by S, has no essential effect on thermal stability of the coordination polyhedron. The complexes involving ONN coordination, realized with the H2L3 ligand, exhibit a comparatively highest thermal stability of the coordination polyhedron.
Abstract
The Mg-, Ca- and Ba-salts of poly(itaconic acid) (PIA) were prepared by treating the aqueous solution of the polyacid with the corresponding metal oxide or hydroxide. The resulting polysalts were analysed by FTIR spectroscopy and thermogravimetry. The results indicate that the polysalts are thermally more stable than the parent PIA, they all degrade in a similar manner, the Ba-salt being the most stable.
The unit cell parameters and the space group of the investigated compound were determined by means of X-ray diffraction.
Summary
The paper describes the results of a study of glasses of the type CuxAs50Se50-xfor x=5, 10 and 15 at.% Cu, by the method of thermomechanical analysis. Values of the thermal coefficients of linear expansion in solid (αg) and visco-plastic (αω) phase were determined. On the basis of the results obtained using the mentioned methods it was possible to determine the specific temperature of the beginning of the softening process of the glass (T g), as well as the temperature of the beginning of the deformation (T ω). It was shown that coefficients of linear expansion decrease with the increase of Cu content. On the other hand, the increase of Cu content caused the increase of the temperatures. The analytical forms of dependence of four physical parameters αg, αω, T g, T ωas a function of the Cu content were fitted.
Transition metal complexes with hydrazides and hydrazones
III. Thermal decomposition of octahedral Co(II) complexes with 1-naphthylacetic acid hydrazide
Abstract
Results of thermal investigations of the amorphous five-component chalcogenide system Ge20As14(SexS1−x)52I14 are presented. Differential thermal analysis (DTA), derivative differential thermal analysis (DDTA), and dilatometry were employed to determine the temperatures of softening and partial crystallization of the samples. Thermal treatment of the samples at 1000°C and recording of the corresponding thermogravimetric (TG) and derivative thermogravimetric (DTG) curves allowed an elucidation of the full mechanism of their decomposition, which proceeds via seven characteristic phase transitions.
