Thermal studies of solid 4-chlorobenzylidenepyruvates of heavy lanthanides(III) and yttrium(III)

Solid-state compounds of general formula LnL(3).2H(2)O, where Ln is heavier trivalent lanthanides and yttrium, L is 4-chlorobenzylidenepyruvate have been synthetised.On heating these compounds decompose in steps. They lose the hydration water in the first step and the thermal decomposition of the anhydrous compounds occurs with the formation of oxochloride (Eu, Gd); mixture of oxide and oxochloride that decrease with increasing of atomic number of metal (Tb-Tm); or oxide (Yb, Lu, Y) as final residue, up to 900degreesC. The dehydration enthalpies found for terbium, holmium, ytterbium and yttrium compounds were: 34.93, 42.40, 57.39 and 62.24 kJ mol(-1), respectively.

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

Solid Ln-OKCO3-DMCP compounds, where Ln represents lanthanides (III) and yttrium (III) ions and DMCP is the anion 4-dimethyiaminocinnamylidenepyruvate, 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.

New chelate complexes of trivalent Y and lanthanides (Eu, Ho, Yb) with a triazene N-oxide: Synthesis, structural characterization and luminescence properties

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Síntese, caracterização e estudo termoanalítico dos 2-metoxibenzalpiruvatos de lantanídios (III), exceto promécio, e de ítrio (III) do estado sólido

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Synthesis, characterization and thermal behaviour of solid-state compounds of 4-methoxybenzoate with lanthanum (III) and trivalent lighter lanthanides

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermal behaviour studies of solid state compounds of cinnamylidenepyruvate with trivalent lanthanides and yttrium (III) in an atmosphere of CO2

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis, characterization and thermal studies on solid compounds of 2-chlorobenzylidenepyruvate of heavier trivalent lanthanides and yttrium(III)

Solid-state compounds of general formula LnL(3)center dot nH(2)O, where Ln represents heavier lanthanides and yttrium and L is 2-chlorobenzylidenepyruvate, have been synthesized. Chemical analysis, simultaneous thermogravimetry-differential analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, elemental analysis and infrared spectroscopy have been employed to characterize and to study the thermal behaviour of these compounds in dynamic air atmosphere.On heating these compounds decompose in four (Gd, Tb, Ho to Lu, Y) or five (Eu, Dy) steps. They lose the hydration water in the first step and the thermal decomposition of the anhydrous compounds up to 1200 degrees C occurs with the formation of the respective oxide, Tb4O7 and Ln(2)O(3) (Ln=Eu, Gd, Dy to Lu and Y) as final residue. The dehydration enthalpies found for these compounds (Eu, to Lu and Y) were: 65.77, 55.63, 86.89, 121.65, 99.80, 109.59, 131.02, 119.78, 205.46 and 83.11 kJ mol(-1), respectively.

Synthesis, characterization and thermal behaviour of solid-state 3-methoxybenzoates of heavy trivalent lanthanides and yttrium(III)

Solid-state Ln(L)(3) compounds, where Ln stands for trivalent Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, and L is 3-methoxybenzoate, have been synthesized. X-ray powder diffractometry, infrared spectroscopy, complexometry and elemental analysis were used to characterize the compounds. In order to study the thermal behaviour of these compounds simultaneous thermogravimetry and differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC) were used. The results provided information on the composition, dehydration, polymorphic transformation, thermal stability and thermal decomposition of the synthesized compounds.

Synthesis, characterization and thermal behaviour of solid-state tartrates of heavy trivalent lanthanides and yttrium(III)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

2-methoxybenzylidenepyruvate with heavier trivalent lanthanides and yttrium(III) - Synthesis and characterization

Solid-state Ln(2-MeO-BP) compounds, where Ln stands for trivalent Eu to Lu and Y(III) and 2-MeO-BP (which is 2-methoxybenzylidenepyruvate) have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffraction, infrared spectroscopy and other methods of analysis were used to characterize and to study these compounds. on the base of the obtained results an Ln(2MeO-BP)(3)center dot H2O general formula can be established.

Complexation of some trivalent lanthanides, scandium(III) and thorium(IV) by benzylidenepyruvates in aqueous solution

The protonation constants of 4-methylbenzylidenepyruvate (4Me-BP) and 4-isopropylbenzylidenepyruvate (4IP-BP) as well as the stability constants of their binary 1:1 complexes with Cu(II), La(III), Pr(III), Sm(III), Eu(III), Yb(III), Sc(III) and Th(IV) have been determined spectrophotometrically in aqueous solution at 25°C and ionic strength 0.500 M, maintained with sodium perchlorate. For all metal ions considered, the stability changes move in the same direction as the pKa of the ligands. Linear free energy relationships, as applied to oxygen donor substances, suggest the -COCOO- moiety as the metal binding site of the ligands. The results are discussed mainly taking into account that benzylidenepyruvates, besides the α-keto canonical form, may display other forms in aqueous solution with changing pH and the possible occurrence of extra intra-ligand charge polarization, induced by metal ions.

4-Dimethylaminocinnamylidenepyruvic acid: Synthesis, characterization and complexation with trivalent lanthanides, yttrium(III), scandium(III), thorium(IV) and uranium(VI) in aqueous solution

4-Dimethylaminocinnamylidenepyruvic acid (H-DMCP)and its sodium salt (Na-DMCP) have been synthesized and characterized. The protonation constant of DMCP as well as the stability constants of its binary 1:1 complexes with trivalent lanthanides (except Pm), Yttrium(III), Scandium(III), Thorium(IV) and Uranium(VI) were determined in an aqueous medium at 25°C and ionic strength 0.500 M. The mode of coordination of this ligand is discussed.

A thermal behaviour study of solid-state cinnamates of the latter trivalent lanthanides and yttrium(III)

Some new compounds of cinnamic acid with the latter trivalent lanthanides and yttrium(III) were synthesized in the solid state. The compounds have the general formula LnL3, where Ln represents trivalent Eu to Lu or Y ions and L is the cinnamate anion (C6H5-CH=CH-COO-). Thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), infrared absorption spectra and X-ray diffraction powder patterns were used to characterize and to study the thermal behaviour of these compounds. © 2002 Elsevier Science B.V. All rights reserved.

Spectroscopic study and thermal behavior of trivalent lanthanides and yttrium(III) chelates of EDTA using TG-DSC, FTIR, and TG-DSC coupled to FTIR

Solid-state compounds of yttrium and lanthanide chelates of ethylenediaminetetraacetic acid have been synthesized. Simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), theoretical and experimental infrared spectroscopy (FTIR), elemental analysis, complexometry and TG-DSC coupled to FTIR were used to characterize and to study the thermal decomposition of these compounds. The results provided information about the composition, dehydration, thermal stability, thermal decomposition and identification of gaseous products evolved during the thermal decomposition of these compounds. The theoretical and experimental spectroscopic data suggest the possible modes of coordination of the ligand with the lanthanum and terbium metal ions. © 2013 Akadémiai Kiadó, Budapest, Hungary.

Spectroscopic, luminescence and in vitro biological studies of solid ketoprofen of heavier trivalent lanthanides and yttrium(III)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)