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Z. Rzączyńska A. Ostasz M. Sikorska-Iwan H. Głuchowska E. Olszewska S. Pikus 《Journal of Thermal Analysis and Calorimetry》2006,84(3):575-579
The complexes
of yttrium(III) and lanthanides(III) with 1,2,4,5-benzenetetracarboxylic acid
were prepared as crystalline solids of the general formula Ln4(C10H2O8)3⋅14H2O. They
are insoluble in water. On heating in air or inert gas atmosphere all compounds
lose water molecules; next anhydrous compounds decompose to oxides. The yttrium
complex and heavy lanthanide (from Ho to Lu) ones crystallize in monoclinic
crystal system. The dehydration does not change the crystal structure of the
compounds. 相似文献
2.
M. Iwan R. Łyszczek A. Ostasz Z. Rzączyńska 《Journal of Thermal Analysis and Calorimetry》2007,88(1):157-162
Properties of lanthanide 1,2,4-benzenetricarboxylates and lanthanide
1,2,4,5-benzenetetracarboxylates obtained by a classical synthesis method
and under hydrothermal conditions were compared. Solid 1,2,4-benzenetricarboxylates
and 1,2,4,5-benzenetetracarboxylates of cerium, neodymium and erbium were
prepared by a classical precipitation method. The same lanthanide compounds
were obtained also from hydrothermal reaction. All obtained products were
examined by elemental analysis. General formulae of complexes were: Ln(1,2,4-btc)·xH2O and Ln4(1,2,4,5-btec)3·yH2O. The thermal analysis
shows that hydrothermal conditions cause the coordination of less number of
water molecules to complex molecule. Because lanthanide ions exhibit the most
often the coordination number equal 8 or 9 one can conclude that the coordination
ability of carboxylic groups under hydrothermal conditions is different from
that under mild ones. Probably, in hydrothermal conditions the carboxylic
groups of 1,2,4-benzenetricarboxylate ions are able to form more coordination
bonds with lanthanide ions than under normal pressure. 相似文献
3.
Summary Rare earth elements 1,3,5-benzenetricarboxylates were prepared as solids of the general formula Ln(C9H3O6)·nH2O, where n=6 for La-Dy and n=4 for Ho-Lu,Y. Their solubilities in water at 293 K are of the order 10-4-10-6 mol dm-3. The IR spectra of the complexes indicate that the carboxylate groups are bridging and bidentate chelates. Hydrated 1,3,5-benzenetricarboxylates
lose water molecules during heating in one step (La-Tb), two steps (Y, Ho-Tm) or three steps (Dy, Yb, Lu). The anhydrous complexes
are stable up to 573-742 K and decompose to oxides (Ce-Lu) at higher temperatures. 相似文献
4.
D. F. Parra P. L. Forster R. Łyszczek A. Ostasz A. B. Lugao Z. Rzączyńska 《Journal of Thermal Analysis and Calorimetry》2013,114(3):1049-1056
The aim of this study has been to gain a fundamental understanding of the mechanisms governing thermal degradation of luminescent poly(3-hydroxybutyrate) (PHB). PHB was doped with diaquatris(thenoyltrifluoroacetonate) europium(III) complex, [Eu(tta)3(H2O)2], and different luminescent systems were obtained. The thermal-stability of the luminescent films was discussed and the products of decomposition were analyzed. Thermal degradation of PHB:Eu(tta)3 x % systems (x = 0, 1, 5, 10, and 15 %) was elucidated by means of thermogravimetric analysis (TG), the thermal-stability decreases with the increase of europium complex concentration. The PHB polymer decomposed with evolution of carbon dioxide and 2-butenoic acid molecules. The TG–FTIR results, of the gaseous degradation products of PHB in nitrogen atmosphere, indicated that the polymer is stable at temperatures up to 200 °C. Polymer matrix at concentrations above 5 % decomposed with evolution of water molecules among the other gaseous products, which implied the presence of a hydrated complex in the system. The luminescent films showed more flexibility due to a loss in crystallinity, which suggested a potential usefulness in technical applications. 相似文献
5.
Sikorska-Iwan M. Mrozek Renata Ostasz A. Rzączyńska Z. 《Journal of Thermal Analysis and Calorimetry》2003,74(2):529-536
The 5-nitro-2-anthranilates of lanthanum(III), samarium(III), terbium(III), erbium(III) and lutetium(III) were obtained as
hydrates having 2.5 mol of water molecules per 1 mol of compound. The compounds are isostructural. The processes of dehydration
and rehydration were investigated. The first step of dehydration does not cause the change of crystal structure. The entire
dehydration gives anhydrous compounds with different structure than the structure of hydrates. However, the dehydration of
La, Sm, Tb and Er is reversible - the rehydration process gives the complexes having the same crystal structure as the initial
compounds. Only the anhydrous lutetium complex under the influence of moisture does not give the starting compound.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Z. Rzączyńska M. Woźniak W. Wołodkiewicz A. Ostasz S. Pikus 《Journal of Thermal Analysis and Calorimetry》2008,91(3):951-956
The complexes of yttrium(III) and lanthanides(III) with 2-aminoterephthalic acid form the isostructural series of triclinic
compounds with a space group P from La to Lu and they have the general formula of Ln2(C8H5O4N)3·8H2O. On heating in air or inert gas atmosphere they lose all water molecules in the temperature range 50–200°C in one or two
steps. The anhydrous compounds are stable from 360 to 435°C and then decompose to oxides. 相似文献
7.
Z. Rzączyńska M. Woźniak W. Wołodkiewicz A. Ostasz S. Pikus 《Journal of Thermal Analysis and Calorimetry》2007,88(3):871-876
The complexes of yttrium(III) and lanthanides(III) with 5-amino-1,3-benzenedicarboxylic acid form two isostructural series
of compounds and have the general formula Ln2(C8H5O4N)3·nH2O, where n = 13 for Y, La-Er and n=9 for Tm, Yb, Lu. They are insoluble in water and stable at room temperature. On heating in air or inert gas atmosphere they
lose all water molecules in several steps. The anhydrous compounds are stable to about 400°C and next decompose to oxides. 相似文献
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