Preparation and thermal behavior of mixture of basic carbonate and 4-dimethylaminocinnamylidenepyruvate with lanthanides (III) and yttrium (III) in the solid state

Abstract

Solid Ln-OHCO3-DMCP compounds, where Ln represents lanthanides (III) and yttrium (III) ions and DMCP is the anion 4-dimethylaminocinnamylidenepyruvate, have been prepared. Thermogravimetry, derivative thermogravimetry (TG, DTG), differential scanning calorimetry (DSC), x-Ray diffraction powder patterns and elemental analysis have been used to characterize the compounds. The thermal stability as well as the thermal decomposition of these compounds were studied using an alumina crucible in an air atmosphere.

Rare-earth metal compounds with a novel ligand 2-methoxycinnamylidenepyruvate: A thermal and spectroscopic approach

“…Steps DTG curves in order to highlight the endothermic event in the first decomposition step. The first mass losses are due to hydration water, which respective percentages observed in Table 1 can be identified in the TG curves (30-120 • C) and associated with the broad endothermic events in the DTA curves with a maximum peak near 100 • C. These mass losses occur in a single step and through a slow process similar to compounds obtained in amorphous state, as previously reported in studies involving rare earth ions [17,18].…”

Synthesis, characterization and thermal behaviour of solid 2-methoxycinnamylidenepyruvate of light trivalent lanthanides

“…This behaviour had already been observed for other cerium compounds. 6,7 For the other anhydrous compounds, Figure 3(c-g), the mass losses up to 783 K (Pr), 853 K (Nd) 823 K (Sm, Eu) and 903 K (Gd), corresponding to exothermic events, are attributed to the oxidation of the organic matter with the formation of a mixture of dioxycarbonate and oxide in no simple stoichiometric relationship. Tests with hydrochloric acid solution on samples heated up to the temperature of formation of this intermediate, as indicated by the corresponding TG curves, confirmed the evolution of CO 2 in all cases.…”

“…The amorphous state is undoubtedly related to the low solubility of these compounds, as has already been observed for lanthanides with other phenyl-substituted derivatives of CP. 6 Infrared spectroscopic data on 2-methoxycinnamylidenepyruvate and its compounds of light trivalent lanthanides are shown in Table 3. The investigation was focused mainly within the 1700-1400 cm -1 range, because this region is potentially the most informative in order to assign coordination sites.…”

“…The formation of dioxycarbonate as intermediate had already been observed during the thermal decomposition of other lanthanide compounds. 6 The last mass loss is ascribed to the thermal decomposition of the mixture of dioxycarbonate/oxide (calculated = 2.57% for Pr; 2.56% for Nd; 2.54% for Sm; 1.68% for Eu and 1.24% for Gd), to the respective oxides: Pr 6 O 11 and Ln 2 O 3 (Ln = Nd to Gd), as final residues. No endothermic peak is observed in the DTA curve due to the thermal decomposition of the intermediate derivative of the carbonate, probably because the heat absorbed in this step is not sufficient to produce a thermal event.…”

“…2 Several metal ion complexes of phenyl-substituted derivatives of cinnamylidenepyruvate, C 6 H 5 (CH) 4 C(O)COO -(CP), have been investigated in aqueous solutions 3 and in the solid state. [4][5][6][7][8][9] These works reported the thermodynamic stability (β 1 ) and spectroscopic parameters (ε 1max , λ 1max ) in aqueous solutions associated with 1:1 complex species. They also report the synthesis and investigation of the compounds in the solid state by means of thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry and other methods of analysis.…”